1 2 3 Previous 358 Replies Latest reply on Dec 4, 2013 3:10 PM by qmabary

    Pi vs BeagleBone-Black

      So, just over a year on from the initial availability of the R-Pi and the new BeagleBone Black is upon us.  They've obviously taken a leaf out of the RPF's playbook and produced a cost reduced version at a price only marginally above the Pi.

       

      I find it interesting that the compromises are very different, for example there's a proper PMIC and the ethernet is not troubled by being connected to USB, however the on-board HDMI seems less capable.

       

      Other differences are in the documentation, I'm currently viewing the pcb gerbers for the beaglebone..  Have yet to see any sign of those for the R-Pi a year later. There's even an up to date devicetree capable kernel too.

       

      Technology has also moved on somewhat, we get a 1GHz Cortex A8 which is better than the Pi, along with various other stuff and lots more GPIO's too.

       

      Ok, so it's clear that I like the look of the new beaglebone, and given the price I'm likely to put any further R-Pi plans on hold until I have a chance to play with this. It's also making things like the Olinuxino-maxi I bought recently look very slow/expensive while still being cheaper than the similarly specced Olinuxino-A13

       

      Some details of the beaglebone-black here http://circuitco.com/support/index.php?title=BeagleBoneBlack

       

      What do the rest of you think ?   I don't expect this to displace the Pi anytime soon, but I expect it to be very attractive to those people who don't simply want to put XBMC on it and duct tape it to the back of the TV..

        • 1. Re: Pi vs BeagleBone-Black
          John Beetem

          BBone Black is very impressive.  Only US$10 more than RasPi at mouser.com (can't find price at element14/Newark).  I'm looking forward to seeing one at Design West tomorrow.

           

          I also noticed today that they've done a major revamp of the http://beagleboard.org/ web site.  It looks like it will be much easier to download operating systems.  Previously it was hard to tell which version was recommended -- RasPi made it quite a bit easier for a new user to get started.

           

          I don't think BBone Black will displace RasPi, because RasPi is still cheaper (especially the Model A) and has a very effective community.  BBone has higher CPU performance, but RasPi probably has better media performance since that's what the BCM2835 was designed for, so people who just want a media engine will prefer it.  But BBone has much better I/O capabilities (clearly now a better choice for geeks*) and has rounded corners so it actually fits in an Altoids tin   And BBone has a full Technical Reference manual.

           

          * I use the definition of "geek" that requires hardware expertise: "you can't spell geek without EE".

          • 2. Re: Pi vs BeagleBone-Black
            ervkosch

            To me its a like comparing BetaMax to VHS.  The Raspberry Pi is cheaper but has less features where as the BeagleBone has more of the features I really want for $10 more (flash memory, more IO, a better and established shield/cape system, more processing power).  If I have a new project I will be looking at BeagleBone. 

             

            Unless TI starts marketing the bat snot out of the unit it will never come close to the volume of the Pi.  Remember that Pi had nearly two years of press before it came out. Most of the press was about the little guy making his dream come try.  The BB Black hardly had any press.  The only way I can see TI getting the word out is as a comeback story that harkens back to old 8 bit PC days.  Otherwise it stay a hobby/engineering tool.

             

            Will I use a Raspberry Pi?  Model A boards yes.  I like the processing power but with a low power consumption for the cost of an Arduino. Model B board now that BB Black is out?  Very unlikely.  I get access to Android and Ubuntu with BB Black. That means I can use PhoneGap/Cordova and Mono to build my apps faster than I can in Python.  Also it has some extra features like true serial connection, power and reset switches, and mounting holes.

             

            I'm not trying to start a flame war.  I like playing with my Pi but this maybe a better option for me.

            • 3. Re: Pi vs BeagleBone-Black

              John Beetem wrote:

               

              BBone Black is very impressive.  Only US$10 more than RasPi at mouser.com (can't find price at element14/Newark).  I'm looking forward to seeing one at Design West tomorrow.

               

              here in the UK, 26.48 GBP for the model B Pi, 27.87 for the beaglebone black - both plus VAT (20% here) or whatever local tax is.

               

              I don't think BBone Black will displace RasPi, because RasPi is still cheaper (especially the Model A) and has a very effective community.  BBone has higher CPU performance, but RasPi probably has better media performance since that's what the BCM2835 was designed for, so people who just want a media engine will prefer it. 

              For me it's not enough cheaper though, so I'm not really in the media engine group   I don't know enough about the BB community at this point, but I suspect the community will grow with a cheaper device that has lots more IO

              And BBone has a full Technical Reference manual.

               

              The docs are quite impressive, especially so early on.

              • 4. Re: Pi vs BeagleBone-Black

                Ervin Kosch wrote:

                I get access to Android and Ubuntu with BB Black. That means I can use PhoneGap/Cordova and Mono to build my apps faster than I can in Python.

                Actually I think that having the A8, not having to do a Raspbian style hf rebuild, and therefore being able to use un-altered distros is a very strong point in the BBB's favour. Thanks for mentioning it.

                I'm not trying to start a flame war.  I like playing with my Pi but this maybe a better option for me.

                Oh, I like mine too. And I agree with a lot of your other points.  The BBB is the closest to the Pi in price that I've seen while being better in some ways, so I think there will be lots of comparisons being made that don't really work when you try to compare the Pi to something like the Sabre-Lite at 6x the price.

                • 5. Re: Pi vs BeagleBone-Black
                  gdstew

                  Actually I think that having the A8, not having to do a Raspbian style hf rebuild, and therefore being able to use un-altered distros is a very strong point in the BBB's favour.

                   

                  Not sure what you mean here. Any SOC will need an altered distro to use the manufacturer specific hardware on that chip no matter what version of ARM is being used.

                  The question I have is whether the drivers for that hardware will be open source. That would be an advantage over the RPi and TI is usually pretty good about that. From

                  what I see it looks like the graphics driver would probably still be proprietary because TI does not own the IP, PowerVR does.

                   

                  I have an original BeagleBoard and I am very glad to see that the BeagleBone Black has 3.3V I/O.  The 1.8V I/O on the BeagleBoard is a RPITA that can require a few

                  very small voltage level translators that really need a custom PCB to use. Overall the BeagleBone Black looks very interesting and I plan to keep close tabs on it.

                   

                  Also just to throw a wild card into the mix, the Cubieboard http://cubieboard.org is now actually available (in somewhat limited quantities) and at $49 is close enough to

                  the RPi and BeagleBone Black to be a competitor. It offers most of the usual features with an Allwinner A10 at 1 GHz, 1 GB RAM, HDMI video, USB, etc.  and at least

                  one feature, a SATA 2 interface that is not found on the others.

                  • 6. Re: Pi vs BeagleBone-Black

                    Gary Stewart wrote:

                     

                    Actually I think that having the A8, not having to do a Raspbian style hf rebuild, and therefore being able to use un-altered distros is a very strong point in the BBB's favour.

                     

                    Not sure what you mean here. Any SOC will need an altered distro to use the manufacturer specific hardware on that chip no matter what version of ARM is being used.

                     

                    Ubuntu, Fedora, Debian etc. don't directly support the Arm core on the Pi at all anymore. They do support the A8. So there's a big difference between recompiling all 10000+ packages in Debian/Fedora specifically for the Pi (what Raspbian & Seneca are doing) compared to needing to recompile just one - the kernel.

                     

                    And you get to the point where you will be able to run Ubuntu on it. AFAIK you still can't run it on the Pi.

                    The question I have is whether the drivers for that hardware will be open source. That would be an advantage over the RPi and TI is usually pretty good about that. From

                    what I see it looks like the graphics driver would probably still be proprietary because TI does not own the IP, PowerVR does.

                    The problem around video drivers is common to all of these Arm platforms, it doesn't seem to matter what GPU you have. Having a distro that's supported upstream may even help here as a driver (even if it is binary only) could support more than one board.

                    Also just to throw a wild card into the mix, the Cubieboard http://cubieboard.org is now actually available (in somewhat limited quantities) and at $49 is close enough to

                     

                    I'd love to get my hands on one, but every time I see a post saying they're back in stock, they've gone by the time I click on the link.  Time will tell if the new beaglebone is available in quantity or not.

                    • 7. Re: Pi vs BeagleBone-Black
                      gdstew

                      So there's a big difference between recompiling all 10000+ packages in Debian/Fedora specifically for the Pi (what Raspbian & Seneca are doing) compared to needing to recompile just one - the kernel.

                       

                      OK, unless you plan to make your own distro I don't understand why you would be recompiling 10000 packages. A majority of those packages have already been compiled for the existing distros and

                      there is nothing inherently ARM CPU version dependent in any applications that are not already compiled as long as you have all the proper tools: GCC, C libraries, and binary utilities which Raspian

                      does provide (not sure about Fedora but I assume they do to).

                       

                      The problem around video drivers is common to all of these Arm platforms, it doesn't seem to matter what GPU you have. Having a distro that's supported upstream may even help here as a driver (even if it is binary only) could support more than one board

                       

                      Yes I know, that is why I pointed it out. I have on several occasions in these forums read complaints against the Raspberry Pi about its GPU being proprietary but as you correctly point out this common

                      with ARM SOCs. If the GPU IP is the property of the ARM SOC manufacturer they could release it if they wanted to. However more often than not they just use somebody else's pre-packaged GPU IP.

                      This is (unfortunately) understandable considering the complexity of GPU design and drivers for it coupled with the desire to get a product on the market in a reasonable time frame. There have been

                      rumours about the two most common GPU providers PowerVR and ARM officially opening up their drivers but as far as I can tell this has not happened yet.

                       

                        I'd love to get my hands on one, but every time I see a post saying they're back in stock, they've gone by the time I click on the link.  Time will tell if the new beaglebone is available in quantity or not.

                       

                      Last time I checked, about two to three weeks ago, they were available from at least one of the links on the Cubieboard web site. I checked Digi Key for the BeagleBone Black, they have none in stock and

                      are quoting 7 weeks before they recieve any. If past history withe the BeagleBoard and BeagleBoard-xM serves it will take the folks at BeagleBoard longer than that.

                      • 8. Re: Pi vs BeagleBone-Black
                        morgaine

                        Spring greetings to you all ...  this thread has brought me out of my forum sabatical, naughty naughty.

                         

                        Seeing the Slashdot thread on BeagleBone Black made me warp over to here post haste, as I guessed you would all be talking about it ... and you were, hehe.  I agree with everything that's been said.

                         

                        Two additional bits of information that slightly change the picture:

                         

                        • Farnell UK says "18584 will be available for delivery on 3 May, 2013", so they're clearly taking this seriously and expect BB Black to sell in much higher volumes than the first BeagleBone.  No surprise of course, price is king.

                         

                        • The BeagleBone's TI Sitara AM3359 contains a pair of integer-only realtime processors running at 200MHz, the Programmable Realtime Unit Subsystem or "PRU".  These can provide waaaaaaay better hard realtime interfacing performance than any program running in Linux user-space, so for hardcore techies who aren't afraid of getting their hands dirty with some pretty simple assembler, the BeagleBone is lightyears ahead of the Pi in interfacing capability.

                         

                        Success has very little to do with engineering merit though, so I won't be making any guesses about how popular this new board will become.  However, for myself, the Pi Model B is now totally dead in the water since it lost its only advantage, which was price.

                         

                        Needless to say, BeagleBone Black is on my shopping list as soon as they're in stock.

                         

                        Morgaine.

                        • 9. Re: Pi vs BeagleBone-Black
                          obcd

                          If finding a cubieboard is a problem, you could take a look on Ebay at the Mele A1000 media player. It's pretty much a cubieboard without the gpio lines. It will cost more than a Pi, but it comes with a supply and a housing. It also has a vga output and connector fitted. It has wifi and ethernet embedded if I remember well. There even is the Mele A2000G with 1Gig of ram.

                          For GPIO, I prefer to use a dedicated microcontroller connected to the linux board with an usb interface. This approach might be a bit more expensive, but it makes it possible to switch from one linux board to another without much hassle. It also makes the system responsive to io changes after a fraction of a second instead of several seconds needed to boot the system. Maybe it's just me being conservative and used to embedded design on 8 bit microcontrollers. Linux adds connectivity to it and makes easy in system programming possible.

                          The Mele also uses the allwinner A10 soc, so booting linux is possible from the sd card. Placing it on the internal flash memory of the player should be possible as well.

                          • 10. Re: Pi vs BeagleBone-Black
                            rdolson

                            The architecture I'm currently designing out for my pet project will have the timing-critical stuff on MSP430s, with a SPI connection up to the Pi for connectivity and user-side control. Looking at doing global clock sync between the Pi and the microcontrollers using the Nordic radio transceivers and a variant of FTSP.

                            • 11. Re: Pi vs BeagleBone-Black
                              gdstew

                              These can provide waaaaaaay better hard realtime interfacing performance than any program running in Linux user-space,

                               

                              There are also several real-time Linux kernel patch sets (Xenomia is one) that can provide way better real time (hard and soft) performance running in "RT" user space than anything running

                              in "normal" user space. They also supply full RT APIs to work with and hardware (when available) supported floating point if you need it. Any RT kernels avaialable for the PRUs ?

                               

                                If finding a cubieboard is a problem, you could take a look on Ebay at the Mele A1000 media player

                               

                              I bought one off of Ebay several months ago which is one of the reasons I'm not as interested in the Cubieboard as I use to be. It does have wi-fi and Ethernet and although it is bit short on the

                              user I/O it does also have serial, I2C (have to add a header), IR remote control and a SATA 2 interface. There are several web sites that provide Linux for the A10 and it already comes with what

                              I think is an Android OS for the media player operation.

                              • 12. Re: Pi vs BeagleBone-Black

                                Gary Stewart wrote:

                                 

                                 

                                OK, unless you plan to make your own distro I don't understand why you would be recompiling 10000 packages. A majority of those packages have already been compiled for the existing distros and

                                there is nothing inherently ARM CPU version dependent in any applications that are not already compiled as long as you have all the proper tools: GCC, C libraries, and binary utilities which Raspian

                                does provide (not sure about Fedora but I assume they do to).

                                You're missing the point, Raspbian is a two man, unofficial, effort to port debian to an arch that the real Debian maintainers are unwilling to support. Raspbian may vanish tomorrow. At which point you will either need to start compiling them yourself, or move to a piece of hardware that someone else is willing to support. You could of course stick with the last Raspbian release if if you like, but that leaves you with other problems.

                                 

                                You're right in that nothing is inherently dependant on the CPU, the issue is simply that Debian doesn't want to support the older version CPU on the Pi, nothing more.

                                • 13. Re: Pi vs BeagleBone-Black

                                  Morgaine Dinova wrote:

                                   

                                  Spring greetings to you all ...  this thread has brought me out of my forum sabatical, naughty naughty.

                                   

                                  Was wondering where you'd been hiding recently

                                  • Farnell UK says "18584 will be available for delivery on 3 May, 2013", so they're clearly taking this seriously and expect BB Black to sell in much higher volumes than the first BeagleBone.  No surprise of course, price is king.

                                   

                                  However after getting an 'in stock' notification from Newark (strange when I'm in the UK), Newark now show 0 in stock and more expected to ship on 28th June - no qty listed...

                                  So I'm not holding my breath just yet.

                                  Success has very little to do with engineering merit though, so I won't be making any guesses about how popular this new board will become.  However, for myself, the Pi Model B is now totally dead in the water since it lost its only advantage, which was price.

                                   

                                  I'd hoped to see something like this where the price difference (in the UK anyway) is approaching zero. Regardless of the merits of each device, it'll be interesting to see what happens next.

                                  • 14. Re: Pi vs BeagleBone-Black

                                    Luc Cool wrote:

                                     

                                    If finding a cubieboard is a problem, you could take a look on Ebay at the Mele A1000 media player. It's pretty much a cubieboard without the gpio lines.

                                    At least for me, it's the GPIO that makes or breaks the device, without them I'm much less interested.

                                     

                                    It will cost more than a Pi,

                                    Approx 60 GBP, so around twice what the Pi costs. Sure it's not a straight comparison.

                                     

                                    The A10 looks like it should be a good SoC and so far the cubieboard looks to be the closest to the sort of board I'm interested in. The danger, as always, is that something better and cheaper may come along by the time they start appearing in volume.

                                     

                                    Either way, interesting times, and I'm really hoping we'll see more and more devices of this type.

                                    • 15. Re: Pi vs BeagleBone-Black
                                      gdstew

                                      You're missing the point, Raspbian is a two man, unofficial, effort to port debian to an arch that the real Debian maintainers are unwilling to support. Raspbian may vanish tomorrow. At which point you will either need to start compiling them yourself, or move to a piece of

                                        hardware that someone else is willing to support. You could of course stick with the last Raspbian release if if you like, but that leaves you with other problems.

                                       

                                      No, I'm not. I think the worst case scenario you just described is not realistic for several reasons. Raspian is the official RPF distribution. There are now over 500,000 Raspberry Pi's out there, most using Raspian. There

                                      is nothing to stop another group of people from taking over or forking Raspian if the current maintainers stopped, and I don't see the RPF not trying to find, or having a lot of trouble finding other people to maintain it if that

                                      happened.

                                       

                                      You're right in that nothing is inherently dependant on the CPU, the issue is simply that Debian doesn't want to support the older version CPU on the Pi, nothing more.

                                       

                                      I don't think that official support from Debian is a prerequisite for a successful distribution. There are precedents for that thought.

                                      • 16. Re: Pi vs BeagleBone-Black
                                        morgaine

                                        selsinork wrote:

                                         

                                        I'd hoped to see something like this where the price difference (in the UK anyway) is approaching zero. Regardless of the merits of each device, it'll be interesting to see what happens next.

                                         

                                        With the price disincentive gone, it'll be great to see comparisons on engineering merit with Raspberry Pi Model B.  The Pi still has a technical advantage in media playback, but that is the only advantage that comes to mind at present, whereas at first glance it seems to be below par in every other technical respect compared to BeagleBone Black.  Detailed comparisons would really be useful.  Perhaps we can do that on the eLinux wiki.

                                         

                                        My interest isn't in media playback but in computing, networking, home automation, embedding, and hardware interfacing, so Pi's media bullet points don't float my boat.  However, it's undoubtedly the case that the masses think otherwise, and good media handling for $35 is what really sold the Pi in vast numbers.  Plus the hype.

                                         

                                        Interesting days ahead.  I hope many other manufacturers join in the fun at this price point.

                                         

                                        Morgaine.

                                        • 17. Re: Pi vs BeagleBone-Black
                                          morgaine

                                          I've started adding information on BeagleBone Black to the eLinux wiki BeagleBone page.

                                          • 18. Re: Pi vs BeagleBone-Black

                                            > With the price disincentive gone, it'll be great to see comparisons on engineering merit with Raspberry Pi Model B.

                                             

                                            Such unbiased comparisons of engineering merit may be difficult to produce.

                                            If you say the BB clock speed is greater than the RPi, you may be met with the

                                            objection that the RPi can be overclocked to the same clock speed. 

                                            If you note the RPI's overclocking potential, you may be met with the objection

                                            that overclocking does not always succeed, and may result in damaged SD cards.

                                            If you note the risks inherent in overclocking, you may be met with the objection

                                            that the risks are overstated and that overclocking the RPi is not actually risky.

                                             

                                            If you say the BB is faster, and therefore better for educational purposes

                                            involving computationally intensive tasks such as IDE's and web browsing,

                                            you may be told that programming should be learned on a slow machine

                                            in order to teach the importance of optimization.

                                             

                                            If you say the BB has better voltage regulation, you may be told that it should

                                            be the responsibility of the power supply to regulate it's own voltage output.

                                             

                                            If you say the BB works with a wider variety of keyboards without dropping

                                            or repeating characters, you may be told that debugging hardware problems

                                            builds character and is a valuable learning experience.

                                            • 19. Re: Pi vs BeagleBone-Black
                                              morgaine

                                              Hahaha. 

                                               

                                              Indeed, the values system of fanbois is a glory to behold, and doesn't obey any known physical laws.

                                               

                                              Fortunately as engineers we can just enumerate the facts that can't be disputed, except by fanbois of course.  And even engineering value judgements of comparative merits and demerits can be given in an NPoV manner as well, and reasonable people will often find them useful, fanbois excepted of course.

                                               

                                              At the end of the day, we can only do our best using the engineer's normal methods of analysis.  Once we've solved world hunger and poverty, then maybe some brave soul will tackle much harder problems like blind fanboism.

                                              • 20. Re: Pi vs BeagleBone-Black
                                                gdstew

                                                coder27 wrote:

                                                 

                                                > With the price disincentive gone, it'll be great to see comparisons on engineering merit with Raspberry Pi Model B.

                                                 

                                                Such unbiased comparisons of engineering merit may be difficult to produce.

                                                If you say the BB clock speed is greater than the RPi, you may be met with the

                                                objection that the RPi can be overclocked to the same clock speed. 

                                                If you note the RPI's overclocking potential, you may be met with the objection

                                                that overclocking does not always succeed, and may result in damaged SD cards.

                                                If you note the risks inherent in overclocking, you may be met with the objection

                                                that the risks are overstated and that overclocking the RPi is not actually risky.

                                                 

                                                If you say the BB is faster, and therefore better for educational purposes

                                                involving computationally intensive tasks such as IDE's and web browsing,

                                                you may be told that programming should be learned on a slow machine

                                                in order to teach the importance of optimization.

                                                 

                                                If you say the BB has better voltage regulation, you may be told that it should

                                                be the responsibility of the power supply to regulate it's own voltage output.

                                                 

                                                If you say the BB works with a wider variety of keyboards without dropping

                                                or repeating characters, you may be told that debugging hardware problems

                                                builds character and is a valuable learning experience.

                                                 

                                                I'd say your bias is pretty clear too.  Why don't you wait for real responses instead of just making them up ? Here's a few for now.

                                                 

                                                16 bit memory data bus vs 32 bit for the Pi. Well at least it uses DDR3 vs. DDR2 for the Pi. That will not make up for the lack of bus width though.

                                                 

                                                The power management chip used by the BeagleBoard Black also uses low dropout voltage regulators for one of its 1.8V and one of its 3.3V supplies. Bad engineering eh Morgaine ? Built

                                                right into the chip from TI no less.

                                                 

                                                The documentation for the real time PRUs is sorely lacking in the AM3359 Technical Reference Manual, 2 pages and no useful hardware description at all. Not even a block diagram. A search

                                                on the TI web site produces only 5 hits all related to forum questions. At least the questions in the forum hint that there is access to better hardware documentation. The PRUs in the 3359 are

                                                an upgrade to an existing device so the documentation may still be be "in the pipeline". They are mostly aimed at providing support for industrial real time communications protocols although

                                                they apparently (no documentation) can be used for other purposes. The only software tools for it is an assembler which is not yet released for public use although mainly due to efforts at

                                                BeagleBoard.org it is supposed to be by the end of this month.

                                                 

                                                The GPU is a proprietary design by PowerVR, which means at least for now, no open source drivers. It supports an OpenGL ES API same as the Pi so X11 hardware acceleration support is not

                                                likely for it either. At least it is a few generations ahead of the Pi.

                                                 

                                                No built in camera interface.

                                                 

                                                Edited (again) to add:

                                                 

                                                It has been my experience that overclocking the CPU does not cause data corruption on the SD card, overclocking the memory does. I had one Pi (out of three) all running with 1 GHHz overclock

                                                that did corrupt data until I changed memory timing from 600 MHz overclock to 500 MHz and have not had a problem with it since. After that I changed all of them to 500 MHz to be safe. Note

                                                that I used the phrase data corruption which is an accurate description as opposed to damaged the SD card which is not.

                                                 

                                                On the plus side for the BB Black:

                                                 

                                                Lots more, and more useful I/O.

                                                 

                                                16 bit LCD interface.

                                                 

                                                More modern ARM architecture.

                                                 

                                                 

                                                From Morgaine:

                                                 

                                                  Indeed, the values system of fanbois is a glory to behold, and doesn't obey any known physical laws.


                                                Fortunately as engineers we can just enumerate the facts that can't be disputed, except by fanbois of course.  And even engineering value judgements of comparative merits and demerits can be given in an NPoV manner as well, and reasonable people will often find

                                                   them useful, fanbois excepted of course.

                                                 

                                                At the end of the day, we can only do our best using the engineer's normal methods of analysis.  Once we've solved world hunger and poverty, then maybe some brave soul will tackle much harder problems like blind fanboism.

                                                 

                                                Yea, these are real good arguments from an normal engineering methods standpoint. Good to see that name calling hasn't fallen out of your favourite responses after your long absence.

                                                • 21. Re: Pi vs BeagleBone-Black
                                                  morgaine

                                                  Gary, evidently you didn't grasp what was being said.  My reply to coder27 was about all fanbois, not just Pi fanbois.  That includes BeagleBone fanbois and all other fanbois as well, because fanboism has no redeeming properties for technical discussion at all.

                                                   

                                                  The technical criticisms that you have presented are very good and useful.  Such observations need to go into the engineering comparisons which are sure to be made between the two boards, and I certainly welcome them.  Knowing and understanding the downsides of any device I use is very important to me.

                                                   

                                                  You seem not to have noticed that I pointed out that Pi Model B still has the lead for media playback.  I pointed this out despite the fact that I personally do not use that feature, because it is a technical feature of great importance to many people and it must be mentioned in any balanced engineering assessment.  I mentioned it because I an not a fanboi of any device nor manufacturer, and any valid engineering assessment must list both pros and consEverything has both pros and cons.  The mark of a fanboi is to praise the pros and deny the cons of his or her precious, and my remarks were directed against that ridiculous lack of objectivity.  I would hope that you would agree with that view..

                                                   

                                                  This is an engineering forum.  Let's try to stick to engineering assessment, and leave fanboism to others.

                                                  • 22. Re: Pi vs BeagleBone-Black

                                                    Gary Stewart wrote:

                                                    No, I'm not. I think the worst case scenario you just described is not realistic for several reasons. Raspian is the official RPF distribution. There are now over 500,000 Raspberry Pi's out there, most using Raspian. There

                                                    is nothing to stop another group of people from taking over or forking Raspian if the current maintainers stopped, and I don't see the RPF not trying to find, or having a lot of trouble finding other people to maintain it if that

                                                    happened.

                                                     

                                                    We'll agree to disagree then. 

                                                     

                                                    That said, it's interesting to look back at the RPF history. Ubuntu was originally going to be the official RPF distribution, until Ubuntu dropped support. Nobody stepped up to take on a port. Next Fedora was to be the official RPF distribution, but Fedora weren't interested, Seneca stepped in (possibly with some help from the RPF) and produced a port, problems with that port caused it to be fairly quietly dropped by the RPF. Every now and again we hear there may be another version, but again nobody seems to have stepped up to help them with it.

                                                     

                                                    Mike Thompson and Peter Green deserve a lot of credit for what they've done with Raspbian, long may it continue. But so far, Mike and Peter appear to be the only ones to have sucessfully taken on such a project. As far as I'm aware it's still mostly a two man show and if I believe what's out there to be read it may even be that Peter has taken on the lions share.

                                                    So with other past failures, partial or otherwise, I don't believe the argument is as easily dismissed as you make out, if it were then surely they'd have found someone to do the same for Ubuntu or Fedora ?

                                                     

                                                    And Liz has said, back on the 1st of March that there's at least a million sold: http://www.raspberrypi.org/archives/3375 so there's a potentially much bigger pool of talent available than you suggest.

                                                    • 23. Re: Pi vs BeagleBone-Black
                                                      morgaine

                                                      selsinork wrote:

                                                       

                                                      Mike Thompson and Peter Green deserve a lot of credit for what they've done with Raspbian, long may it continue. But so far, Mike and Peter appear to be the only ones to have sucessfully taken on such a project. As far as I'm aware it's still mostly a two man show and if I believe what's out there to be read it may even be that Peter has taken on the lions share.

                                                       

                                                      Fortunately that problem will disappear as soon as RPF brings out a next gen Raspberry Pi based on a SoC with a more modern ARM, which can then be supported by standard portable Linux distributions.  That will undoubtedly happen, if we make the very reasonable assumption that the RPF project continues and prospers.  The only question is when.

                                                      • 24. Re: Pi vs BeagleBone-Black

                                                        Gary Stewart wrote:

                                                         

                                                        The power management chip used by the BeagleBoard Black also uses low dropout voltage regulators for one of its 1.8V and one of its 3.3V supplies. Bad engineering eh Morgaine ? Built

                                                        right into the chip from TI no less.

                                                         

                                                        Did you catch the table in the BBB SRM showing power consumption ?   I was very interested in the Kernel Idling Display Blank figures of 280mA @ 5v, my Pi shows ~410mA in the same condition. So something is doing a better job.

                                                         

                                                        Do you have any information on whether LDO3&4 outputs are configured as LDO's or Load Switches ?  I couldn't find anything and I'd like to understand where the differences are, but I think we can safely assume these LDO's are not the same as the 1117's on the Pi. Whether that's the source of the difference or something else is more difficult to ascertain. 

                                                        I've replaced both the 3.3v & 1.8v LDO's on a couple of my Pi's with switchers based on a TPS54231 and can get down from 410mA to approx 295mA so this has me interested.

                                                        • 25. Re: Pi vs BeagleBone-Black

                                                          > The only question is when.

                                                           

                                                          We have some clues.

                                                          The 1st gen RPi was based on the same cpu as the Roku 2,

                                                          and both were announced mid 2011.

                                                          The Roku 3 became available recently, using the next generation

                                                          Broadcom cpu with dual core Cortex A9, with only a slight increase

                                                          in price over the Roku 2.

                                                          Sony has already mentioned the 2nd gen RPi.

                                                          Liz has downplayed the Sony announcement.

                                                          • 26. Re: Pi vs BeagleBone-Black

                                                            Morgaine Dinova wrote:

                                                             

                                                            The only question is when.

                                                            I've not been following it closely, but everytime I see some mention of some form of updated Pi the official answer seems to come back as 'not for the forseeable future'. Possibly that's understandable - they still need to make some money from the long awaited camera module, try getting them into schools, and then there's that other as yet unused connector they might want to use.

                                                            So while you're right, would you bet on the 'when' being anytime soon ?

                                                            • 27. Re: Pi vs BeagleBone-Black
                                                              obcd

                                                              A more modern soc....

                                                              That's the nice thing about the allwinner and the Ti arm cores as well (Not sure about the last one)

                                                              They have pin compatible dual core versions of the same soc.

                                                              Quad core probably already exist as well, but I wouldn't bet on that right now.

                                                               

                                                              Low dropout voltage regulators are not a bad design. The Pi supply is a bad design as it expects 5V with a maximum deviation of 5% and it expects every charger on the market with a micro usb plug do deliver that stable. (Which isn't the case)

                                                              I also prefer something that accepts like 9 - 15V. The wider the range the more likely it will work and keep working, even if the supply adapter capacitors start to dry out.

                                                               

                                                              I am also always a bit confused when people focus on the Pi pricetag. It's a bit like going to a computer shop and buying a motherboard and cpu, saying you got a pc for 120 euro.

                                                               

                                                              Ok, you can use it without a housing, but you will need a supply, a keyboard, a screen, a mouse and a storage device. Assuming you have those lying around is not a fair comparison in my opinion. 

                                                              • 28. Re: Pi vs BeagleBone-Black

                                                                coder27 wrote:

                                                                 

                                                                Sony has already mentioned the 2nd gen RPi.

                                                                Pointer ?

                                                                Liz has downplayed the Sony announcement.

                                                                One of the places I worked had a running in-house joke that the lifetime of a particular product was only about six weeks. There'd then be a 'new' product, with different code names etc. usually the only difference was a minor tweak here and there, or no difference at all apart from some plug in part.

                                                                 

                                                                So I can understand some downplaying as a 2nd gen RPi could mean almost anything while quite rightly being seen as a 'new' product by Sony.  We'll find out sooner or later, but neither a minor revision or a fully new design would surprise me.

                                                                • 29. Re: Pi vs BeagleBone-Black

                                                                  Luc Cool wrote:

                                                                   

                                                                  A more modern soc....

                                                                  That's the nice thing about the allwinner and the Ti arm cores as well (Not sure about the last one)

                                                                  They have pin compatible dual core versions of the same soc.

                                                                  Quad core probably already exist as well, but I wouldn't bet on that right now.

                                                                  Freescale's iMX6 has, AFAIK, single, dual and quad versions in pin-compatible packaging along with some reduced feature versions of their core in different packaging.  It's used in the Sabre-Lite boards amongst others, better feature set and an inflated price to go with it.

                                                                   

                                                                  I am also always a bit confused when people focus on the Pi pricetag. It's a bit like going to a computer shop and buying a motherboard and cpu, saying you got a pc for 120 euro.

                                                                   

                                                                  Ok, you can use it without a housing, but you will need a supply, a keyboard, a screen, a mouse and a storage device. Assuming you have those lying around is not a fair comparison in my opinion. 

                                                                  The BBB seems to be in the same boat, it certainly appears they've cut all the same corners by not supplying a PSU etc either. The Pi and BBB are approx 2 GBP different and you'll need all the same extras for both. That makes a straight comparison of what you get for your money interesting, whether the base price is $35 or $350 isn't so important.  Much more difficult to compare the relative merits of a $35 device to a $350 device objectively, especially if you only have $100.

                                                                  • 31. Re: Pi vs BeagleBone-Black
                                                                    gdstew

                                                                    Morgaine Dinova wrote:

                                                                     

                                                                    Gary, evidently you didn't grasp what was being said.  My reply to coder27 was about all fanbois, not just Pi fanbois.  That includes BeagleBone fanbois and all other fanbois, because fanboism has no redeeming properties for technical discussion at all.

                                                                     

                                                                    The technical criticisms that you have presented are very good and useful.  Such observations need to go into the engineering comparisons which are sure to be made between the two boards, and I certainly welcome them.  Knowing and understanding the downsides of any device I use is very important to me.

                                                                     

                                                                    You seem not to have noticed that I pointed out that Pi Model B still has the lead for media playback.  I pointed this out despite the fact that I personally do not use that feature, because it is a technical feature of great importance to many people and it must be mentioned in any balanced engineering assessment.  I mentioned it because I an not a fanboi of any device nor manufacturer, and any valid engineering assessment must list both pros and consEverything has both pros and cons.  The mark of a fanboi is to praise the pros and deny the cons of his or her precious, and my remarks were directed against that ridiculous lack of objectivity.  I would hope that you would agree with that view..

                                                                     

                                                                    This is an engineering forum.  Let's try to stick to engineering assessment, and leave fanboism to others.

                                                                     

                                                                    Your repeated use of fanbois in Rapsberry Pi forums as well as the explicit use of Raspberry Pi fanbois on several occasions, and your use of it on more than one occasion when

                                                                    it was simply not appropriate (see next sentence) makes it clear what you mean. The entire content of the "fanboi" post was clearly lacking any of the objective engineering

                                                                    assessment you insist on from everybody else and in no way contributed useful engineering information or even interesting opinion to this forum which makes the last two

                                                                    sentences of yours quoted above seem rather strange (not my first choice of words).

                                                                     

                                                                    It is clear from my post that I already have a firm grasp on the concept of pros and cons, how you missed that I do not know.

                                                                     

                                                                    I didn't miss anything in your post(s), I just didn't find it germane to what I was responding to.

                                                                     

                                                                    As far as fanbois in these forums go there are a few, but I find you use the term more often than is warranted by their actual presence. In this case none have been present so

                                                                    far so why did you feel compelled to use it ? As far as it goes I accept them as a fact of life and rarely find the need to call them out. I just tend to ignore them. Doing anything

                                                                    else is a waste of time because they don't listen anyway and ignoring them does not "feed the beast".

                                                                     

                                                                    Now if you don't mind I will attempt to go back to useful engineering assessment mode.

                                                                    • 32. Re: Pi vs BeagleBone-Black
                                                                      gdstew

                                                                      Without knowing why each of them decided to turn RPF down knowing the history doesn't say much of anything useful. I'm not sure if any of the ones you mentioned

                                                                      already had ARM ports or not, I know Debian did. It could have been that they were already too busy or didn't think that there would be enough interest in the PI to

                                                                      make it worth their time and effort. But strangely enough, now there is a Fedora port, and an Arch port, and a BSD port. Did I miss any ?

                                                                       

                                                                      One last point. Being officially supported by Debian does not mean that if the distribution maintainers decide to call it quits Debian will step in and help. This leaves

                                                                      any distribution officially supported or not in the same boat as Raspian should they quit.

                                                                      • 33. Re: Pi vs BeagleBone-Black
                                                                        morgaine

                                                                        selsinork wrote:

                                                                         

                                                                        So while you're right, would you bet on the 'when' being anytime soon ?

                                                                         

                                                                        I have no idea, but I do think that it's likely that their next-gen Pi plans have just accelerated with the release of BeagleBone Black.  Now they finally have competition within their price niche, whereas before they didn't.

                                                                         

                                                                        This assumes of course that they are sensitive to competition, but I think that they are, judging by the way that they're downplaying the significance of BBB in typical fanboi style.  I don't want to guess at dates or even years, but they don't have forever to respond or they'll lose their market completely.  Time marches on, and clearly the competition has arrived.

                                                                        • 34. Re: Pi vs BeagleBone-Black
                                                                          morgaine

                                                                          Gary: Good, I'm glad to see that we both agree on the worthless contribution that fanbois make to technical discussion.  Let there be none here, for any board or device regardless of manufacturer.

                                                                           

                                                                          And that means being willing to point out the downsides and areas of improvement of everything we discuss, without fear of treading on irrelevant fanboi sensitivities.  Technology is technology, and discussing where it fails and suggesting how it can be improved is part of the engineering process.

                                                                          • 35. Re: Pi vs BeagleBone-Black

                                                                            Gary Stewart wrote:

                                                                             

                                                                            Did I miss any ?

                                                                            http://en.wikipedia.org/wiki/Raspberry_pi says yes, you missed quite a few, but probably a lot of them are much less mainstream. Curiously, Fedora is missing from that list.

                                                                            http://elinux.org/RPi_Distributions has an even more impressive list, a bunch of which I've never even heard of.

                                                                             

                                                                            Package counts are interesting, I was way off with 10000 packages in Debian it seems as they quote 35000+.

                                                                             

                                                                            The one mainstream choice I'd previously thought was conspicuously absent, OpenSUSE seems to be there as well.

                                                                             

                                                                            However reading the post on the RPF forums linked to from the OpenSUSE entry suggests there may be other troubles ahead for Arm - not just the Pi - with the NWFPE removal from upstream kernels due to licensing.

                                                                            Should be interesting as it could have all sorts of effects if you can no longer distribute the old code while not having a way forward. Sounds like this will break all the softfloat distros, likely some of the hardfloat ones depending on the exact VFP, and upstream might only want to deal with newer CPU's - leaving the RPF to re-engineer a solution for the particular combination we have.

                                                                             

                                                                            So, something learned for me there..

                                                                            • 36. Re: Pi vs BeagleBone-Black
                                                                              gdstew

                                                                              Is their 280 mA with or without USB (keyboard/mouse etc.) or Ethernet connections ? Is your 410 mA with or without USB or Ethernet connections ? I pull

                                                                              a fairly consistent 700 mA on mine with a full complement of I/O attached but given what the Pi was designed for and the major constraints used for that

                                                                              design (something people seem to lose track of or just plain ignore all the time) I don't have any problems with it using 3.5W. For one of the more mundane

                                                                              uses I have in mind for one of mine, a DNS/DHCP server, 3.5W would be about 30x less than doing it with a normal old "junk" PC. For the project I would

                                                                              probably use the BeagleBoard Black for (robot) the less power used the better.

                                                                               

                                                                              The previous argument about linear LDOs was simply that they were not the best solution (some even said they were a bad engineering solution which is silly)

                                                                              for  powering the Pi. There is some merit to the argument of using a switcher as far as allowing a wider selection of input voltages and efficiency goes however

                                                                              given the pricing and size contraints of what it was designed for (again) there really is not much choice. It would also have required either a multi-output

                                                                              switcher or the same number of LDOs (one for 3.3V and one for 1.8V) already on the Pi.

                                                                              • 37. Re: Pi vs BeagleBone-Black
                                                                                gdstew

                                                                                You missed the sarcasm (OK it might not have been obvious) and the point (the Pi has become important enough for several of the ones that passed up on the opportunity earlier to

                                                                                port to it now).

                                                                                • 38. Re: Pi vs BeagleBone-Black

                                                                                  Gary Stewart wrote:

                                                                                   

                                                                                  Is their 280 mA with or without USB (keyboard/mouse etc.) or Ethernet connections ? Is your 410 mA with or without USB or Ethernet connections ? I pull

                                                                                   

                                                                                  The SRM says their figures are with HDMI monitor, usb hub, 4G thumb drive, ethernet @100Mb, serial debug cable. I basically have Pi, ethernet, sdcard, max3232 and a few temperature sensors, no usb devices for 410mA. So a reasonably similar setup.

                                                                                   

                                                                                  I'm about 310mA with the switchers and a GPS receiver for an NTP clock. As single purpose devices I don't tend to have much running on them - ntp isn't exactly processor intensive.

                                                                                   

                                                                                  So I'm waiting impatiently for my BBB to arrive so I can swap out a Pi and compare it in the same environment.

                                                                                   

                                                                                  The previous argument about linear LDOs was simply that they were not the best solution (some even said they were a bad engineering solution which is silly)

                                                                                  for  powering the Pi. There is some merit to the argument of using a switcher as far as allowing a wider selection of input voltages and efficiency goes however

                                                                                  given the pricing and size contraints of what it was designed for (again) there really is not much choice. It would also have required either a multi-output

                                                                                  switcher or the same number of LDOs (one for 3.3V and one for 1.8V) already on the Pi.

                                                                                   

                                                                                  I really don't have a problem with the LDO's (and my switchers cost way too much to use on the Pi), I'm just interested in the different design compromises. Especially when the costs are so similar.

                                                                                  Yes time and technology marches on, but it does make you wonder that if the BBB can use a composite pmic (with some switchers and some LDO's) while being so close in cost, could the Pi have done so too ?  Or if it couldn't a year or more ago, could it do so today..

                                                                                  • 39. Re: Pi vs BeagleBone-Black

                                                                                    Gary Stewart wrote:

                                                                                     

                                                                                    You missed the sarcasm

                                                                                    Not so much. But we still fundamentally disagree on that point. I still don't think that an unofficial, one man port is anything like the same as a fully upstream supported port done by the distro themselves.

                                                                                    I do however value the interesting discussion and the differeing viewpoint, even when I suspect we'll never agree on that particular subject

                                                                                    • 40. Re: Pi vs BeagleBone-Black
                                                                                      gdstew

                                                                                      selsinork wrote:

                                                                                       

                                                                                      Gary Stewart wrote:

                                                                                       

                                                                                      Is their 280 mA with or without USB (keyboard/mouse etc.) or Ethernet connections ? Is your 410 mA with or without USB or Ethernet connections ? I pull

                                                                                       

                                                                                      The SRM says their figures are with HDMI monitor, usb hub, 4G thumb drive, ethernet @100Mb, serial debug cable. I basically have Pi, ethernet, sdcard, max3232 and a few temperature sensors, no usb devices for 410mA. So a reasonably similar setup.

                                                                                       

                                                                                      I'm about 310mA with the switchers and a GPS receiver for an NTP clock. As single purpose devices I don't tend to have much running on them - ntp isn't exactly processor intensive.

                                                                                       

                                                                                      So I'm waiting impatiently for my BBB to arrive so I can swap out a Pi and compare it in the same environment.

                                                                                       

                                                                                      The previous argument about linear LDOs was simply that they were not the best solution (some even said they were a bad engineering solution which is silly)

                                                                                      for  powering the Pi. There is some merit to the argument of using a switcher as far as allowing a wider selection of input voltages and efficiency goes however

                                                                                      given the pricing and size contraints of what it was designed for (again) there really is not much choice. It would also have required either a multi-output

                                                                                      switcher or the same number of LDOs (one for 3.3V and one for 1.8V) already on the Pi.

                                                                                       

                                                                                      I really don't have a problem with the LDO's (and my switchers cost way too much to use on the Pi), I'm just interested in the different design compromises. Especially when the costs are so similar.

                                                                                      Yes time and technology marches on, but it does make you wonder that if the BBB can use a composite pmic (with some switchers and some LDO's) while being so close in cost, could the Pi have done so too ?  Or if it couldn't a year or more ago, could it do so today..

                                                                                       

                                                                                      Yes the prices are close. However one of the major design considerations for the Pi was the $35 price point which they achieved. I'm sure there are more than one or two things

                                                                                      they would have preferred to do differently but that is how engineering works when rubber meets road. I know, I've been there a few times. Although there is a good degree of crossover

                                                                                      in what they both do I still feel that they are fundamentally aimed at different markets. The Pi market is much more narrowly focused. The BB Black is much more general purpose. That

                                                                                      probably accounts for most of the price difference. Personally I'm very excited about the BB Black.

                                                                                       

                                                                                      One of the nice things RPF did do recently was to double the memory for the same price. So there is room for improvements as technology advances. It will be interesting to see

                                                                                      what happens to both of them (and others to come ?) over the next couple of years.

                                                                                      • 41. Re: Pi vs BeagleBone-Black
                                                                                        gdstew

                                                                                        I'd like to add another pro for the BeagleBoard Black.

                                                                                         

                                                                                        With the exceptions of the integer real time processors PRU-ICSS (not sure at this point why that is), and the PowerVR GPU for

                                                                                        well known reasons, the AM3359 technical documentation from TI is excellent to the point of overwhelming. The Technical Reference

                                                                                        Manual is over 4000 pages. No I did not accidentally add any zeros !

                                                                                        • 42. Re: Pi vs BeagleBone-Black

                                                                                          Gary Stewart wrote:

                                                                                           

                                                                                          The Technical Reference Manual is over 4000 pages. No I did not accidentally add any zeros !

                                                                                          One of the other boards I have some interest in is the Sabre-Lite, Freescale have a ref manual for their iMX6 that's bigger, close to 6k pages if memory serves.

                                                                                          Similar omissions for the GPU and their secure boot module though.

                                                                                           

                                                                                          I couldn't agree more, copious documentation like these two have is the way forward and really should become the norm instead of the exception.

                                                                                          • 43. Re: Pi vs BeagleBone-Black
                                                                                            morgaine

                                                                                            Gary Stewart wrote:

                                                                                             

                                                                                            With the exceptions of the integer real time processors PRU-ICSS (not sure at this point why that is), and the PowerVR GPU for well known reasons, the AM3359 technical documentation from TI is excellent to the point of overwhelming.

                                                                                             

                                                                                            You're right about the proprietary GPU, that seems to be an endemic problem for open source in the industry.  It's not true for the PRU-ICSS though.

                                                                                             

                                                                                            The PRU-ICSS is fully documented in the Technical Reference Manual SPRUH73C, with the entirety of chapter 4 (250 pages) devoted to it.  Also, there is a full package of PRU-related materials on Github, including more documentation and source code of the PRU's PASM assembler, a Linux loader, demos, etc.  I've even checked that the assembler compiles and it does.

                                                                                             

                                                                                            The BeagleBone materials on Github are at https://github.com/beagleboard/am335x_pru_package

                                                                                             

                                                                                            The PRU has been used successfully in quite a number of projects as a quick web search shows, and this long predates the BeagleBone Black since the original BeagleBone uses a slightly different version of the same AM3359 SoC.

                                                                                             

                                                                                            Morgaine.

                                                                                             

                                                                                            Addendum: Repeating the link to TI's wiki pages on PRU which I gave in my first post on this thread, in case it was missed when looking for docs.  There is a developers' link at the bottom of that first page.

                                                                                            • 44. Re: Pi vs BeagleBone-Black
                                                                                              gdstew

                                                                                              Morgaine,

                                                                                               

                                                                                              A search of the TI website for SPRUH73C turns up with zero results. SPRUH73H gives me the same technical reference manual I already have. That manual has a very brief

                                                                                              two page description of the PRU-ICSS but little else, not even a block diagram. According to that technical reference manual this is an upgraded version of the original so it

                                                                                              may be that the documentation hasn't been released yet. I have also searched the TI website for PRU-ICSS which turns up 5 hits, all of them from entries in forums. A couple

                                                                                              of the entries clearly show that more hardware information is available but no hint as to which one or where.

                                                                                              • 45. Re: Pi vs BeagleBone-Black
                                                                                                John Beetem

                                                                                                Gary Stewart wrote:

                                                                                                 

                                                                                                A search of the TI website for SPRUH73C turns up with zero results. SPRUH73H gives me the same technical reference manual I already have. That manual has a very brief

                                                                                                two page description of the PRU-ICSS but little else, not even a block diagram. According to that technical reference manual this is an upgraded version of the original so it

                                                                                                may be that the documentation hasn't been released yet. I have also searched the TI website for PRU-ICSS which turns up 5 hits, all of them from entries in forums. A couple

                                                                                                of the entries clearly show that more hardware information is available but no hint as to which one or where.

                                                                                                It seems that SPRUH73 has shrunk from H to C.  I tried to find some Am335x documents and it looks like the TI site is currently screwed up.  Maybe the people who know how to fix it are all at Design West (formerly ESC).

                                                                                                 

                                                                                                The PRUSS documentation is definitely in version C.  Maybe TI decided to put it into a separate document, but have screwed up access to that document or else it hasn't been approved for release.  You might try searching for SPRUH73C on the Internet to see if you can download it from somewhere else.

                                                                                                 

                                                                                                It's also possible that TI decided to omit PRUSS from the Am335x TRM and make people use the wiki.  If that's true, it's too bad because the TRM is a lot better formatted and prints better.  Some PRUSS documentation has never been in the TRM, such as opcode encoding (which is in the wiki).

                                                                                                • 46. Re: Pi vs BeagleBone-Black
                                                                                                  morgaine

                                                                                                  SPRUH73C is considered the "canonical" AM335x TRM by the BeagleBone community and a lot of people have mirrored it  --- the very first hit in Google will get you it, for example.  Documents are always in transition and the TRM is no exception, which appears to be the reason why the latest SPRUH73H has only a 2-page placeholder for that chapter.  We're only guessing and I haven't seen it confirmed yet, but I suspect the technical author just has a lot of work.  It's not like the PRU were a secret or anything, it's already been documented officially in SPRUH73C and used extensively in the community.

                                                                                                   

                                                                                                  I'm still trying to get some info on whether a forthcoming SPRUH73  'I' release will contain updated PRU info or whether we should continue using SPRUH73C from here on, but it doesn't make a huge amount of difference --- just grab SPRUH73C for now.  The BeagleBone Black's slightly upgraded AM3359 is still a AM3359 after all, and its PRU hasn't changed since the original BeagleBone was released or there would be a new datasheet for it.

                                                                                                   

                                                                                                  We have the required info available to the community already, but if the large hole in the latest SPRUH73H concerns you massively then perhaps you could ask someone who can answer authoritatively about it?  I'd be interested in the answer too.  I'd certainly prefer the latest doc to be complete, but I can't obsess about it when the BeagleBone community already has the PRU info in SPRUH73C and considers it canonical for BeagleBone ... and hence for BeagleBone Black too.

                                                                                                   

                                                                                                  Morgaine.

                                                                                                  • 47. Re: Pi vs BeagleBone-Black
                                                                                                    gdstew

                                                                                                    Found it, thanks. Weird that TI does not seem to have a copy of this document on their site. In an earlier search I googled PRU-ICSS but did not see any PDFs.

                                                                                                    Obviously I didn't look through enough pages.

                                                                                                     

                                                                                                    I'm not massively interested but I was thinking about using one or both of them to help with a project I have in mind so I wanted to an idea of what they were

                                                                                                    capable of, how many of their non-communications I/O pins were available to use on the BB Black, and how they shared data with the ARM.

                                                                                                    • 48. Re: Pi vs BeagleBone-Black
                                                                                                      morgaine

                                                                                                      The PRU is certainly a very interesting facility, and I'm looking forward to playing with it myself.  It'll be quite nostalgic to return to assembly code programming and examine a new set of instruction encodings.

                                                                                                       

                                                                                                      This is actually very topical in this Pi group, because in many threads I've been promoting the idea that the best way of using Pi for hardware interfacing is with the help of a bare metal microcontroller.  The Unix model of operating systems just isn't designed for realtime programming, and no matter what realtime patches you apply or which realtime scheduler you enable (I've played with both), you're never going to get anything like the low response latency and absence of jitter that you can get from the cheapest of microcontrollers.  A far better approach is therefore to combine a bare-metal micro with a *nix system, and let the latter control the former with high-level commands which the micro then executes with very tight timing constraints.

                                                                                                       

                                                                                                      The two PRU cores will of course be the "bare metal microcontrollers" in our AM3359-based scenario, and we won't need a single bit of extra glue logic to achieve it.  This is certainly going to make for some very interesting projects.

                                                                                                       

                                                                                                      Morgaine.

                                                                                                      • 49. Re: Pi vs BeagleBone-Black
                                                                                                        obcd

                                                                                                        I agree upon the idea of a bare metal microcontroller for real time behavour.

                                                                                                        Programming in assembly however doesn't seem an efficient way of doing things.

                                                                                                        It's like almost 10 years ago I used assembly, and only to create small procedures that were called from C.

                                                                                                        On the other hand, it will limit your design to just the beagle boards.

                                                                                                        Most modern microcontrollors already contain the glue logic for an usb or spi interface.

                                                                                                        Not needing extra hardware will reduce the hardware price of your design, but the development effort and time will be bigger.

                                                                                                        • 50. Re: Pi vs BeagleBone-Black
                                                                                                          morgaine

                                                                                                          That's true, yes.

                                                                                                           

                                                                                                          Well it wouldn't be too huge a task to port smallc to issue PASM code for the PRU, as long as totally dumb code generation is OK.  A lot of the 200MHz would be used up in overheads though, and the tradeoff may not be worth it.  I guess this would have to examined on a case by case basis.

                                                                                                           

                                                                                                          In a more "Pi-oriented" context, programming small pieces of tight code in assembler would have immense educational benefit for budding future engineers, so programmer efficiency and code maintainability would not be so high up on the list of requirements as they are in industry.  Programming the PRUs in assembler would be an effective way of exposing inquisitive minds to low level details.

                                                                                                           

                                                                                                          I could have put this kind of integrated architecture to very good use back when I was churning out EE degree students.  It provides very significant educational gains for very little staff and student pain, and EE students absolutely must understand what's going on at an instruction set level and below otherwise they'll have no hope of one day designing such hardware.  The PRU SS gets a big thumbs up from that angle.  Experience will tell how this works out in practice.

                                                                                                           

                                                                                                          Morgaine.

                                                                                                          • 51. Re: Pi vs BeagleBone-Black
                                                                                                            gdstew

                                                                                                            Morgaine Dinova wrote:

                                                                                                             

                                                                                                            The PRU is certainly a very interesting facility, and I'm looking forward to playing with it myself.  It'll be quite nostalgic to return to assembly code programming and examine a new set of instruction encodings.

                                                                                                             

                                                                                                            This is actually very topical in this Pi group, because in many threads I've been promoting the idea that the best way of using Pi for hardware interfacing is with the help of a bare metal microcontroller.  The Unix model of operating systems just isn't designed for realtime programming, and no matter what realtime patches you apply or which realtime scheduler you enable (I've played with both), you're never going to get anything like the low response latency and absence of jitter that you can get from the cheapest of microcontrollers.  A far better approach is therefore to combine a bare-metal micro with a *nix system, and let the latter control the former with high-level commands which the micro then executes with very tight timing constraints.

                                                                                                             

                                                                                                            The two PRU cores will of course be the "bare metal microcontrollers" in our AM3359-based scenario, and we won't need a single bit of extra glue logic to achieve it.  This is certainly going to make for some very interesting projects.

                                                                                                             

                                                                                                            Morgaine.

                                                                                                             

                                                                                                            You really need to get better acquainted with real time Linux. There are many companies that use it for products and several that specialize in producing real time tools and solutions using Linux.

                                                                                                             

                                                                                                            First and foremost the "amount" of real time needed is very application dependent. Real time versions of Linux are able to handle latency requirements below 100 uS. This puts a wide range of hard

                                                                                                              and soft real time applications within its reach and it is quite capable of handling them.

                                                                                                            • 52. Re: Pi vs BeagleBone-Black
                                                                                                              shabaz

                                                                                                              100usec while good, is honestly not that great. It would be insufficient for many tasks where you need to take rapid action.

                                                                                                              Even many ancient typical real-time OSs designed with priority based pe-emptive scheduling have a latency of 20-50usec and that's with

                                                                                                              slow processors.

                                                                                                              However, there will always be cases where a separate processor (dedicated to a few specific tasks) or logic (maybe programmable)

                                                                                                              is useful. Personally I'd want to use a C compiler though, not assembler any more.

                                                                                                              This is the classic case of whether just a simple executive is sufficient, or whether a full-blown UNIX type OS is needed.

                                                                                                              Not everything requires (or will perform better) with the latter.

                                                                                                              • 53. Re: Pi vs BeagleBone-Black
                                                                                                                gdstew

                                                                                                                shabaz wrote:

                                                                                                                 

                                                                                                                100usec while good, is honestly not that great. It would be insufficient for many tasks where you need to take rapid action.

                                                                                                                Even many ancient typical real-time OSs designed with priority based pe-emptive scheduling have a latency of 20-50usec and that's with

                                                                                                                slow processors.

                                                                                                                However, there will always be cases where a separate processor (dedicated to a few specific tasks) or logic (maybe programmable)

                                                                                                                is useful. Personally I'd want to use a C compiler though, not assembler any more.

                                                                                                                This is the classic case of whether just a simple executive is sufficient, or whether a full-blown UNIX type OS is needed.

                                                                                                                Not everything requires (or will perform better) with the latter.

                                                                                                                 

                                                                                                                100 uS will work for a wide range of  real time applications (your opinion of greatness not withstanding) but not all of them. 20 - 50uS is not really all that

                                                                                                                much faster and I am not talking about using the latest-greatest multi-core speed demon processor (not even close) for sub 100 uS either. In fact I would

                                                                                                                be very surprised if there were more real time applications that required 20 - 50 uS latencies than not.

                                                                                                                 

                                                                                                                  It would be insufficient for many tasks where you need to take rapid action

                                                                                                                 

                                                                                                                Thanks for stating the obvious but the definition rapid is clearly a part of "very application dependent". Since there are many companies that use real time

                                                                                                                Linux and many that are thinking about switching over to it that would tend to indicate that it is "rapid" enough for them.

                                                                                                                 

                                                                                                                  However, there will always be cases where a separate processor (dedicated to a few specific tasks) or logic (maybe programmable)is useful.

                                                                                                                 

                                                                                                                That is why I am interested in it. For my particular application just one of these processors is probably overkill but it would relieve the ARM core of a rather

                                                                                                                mundane but important task.

                                                                                                                 

                                                                                                                While I have no problems with assembly language, I have been using it on multiple processors for over 30 years now, I would also prefer to program in C.

                                                                                                                Real time applications and RISC cores are complex enough to deal with without also having to deal with more tool complexity than needed.

                                                                                                                • 54. Re: Pi vs BeagleBone-Black
                                                                                                                  rdolson

                                                                                                                  Do you have a recommendation for a real-time linux that works on the Pi?

                                                                                                                  • 55. Re: Pi vs BeagleBone-Black
                                                                                                                    shabaz

                                                                                                                    "100 uS will work for a wide range of real time applications"

                                                                                                                     

                                                                                                                    In many cases, perhaps you really should be looking at additional

                                                                                                                    hardware to offload this and if required, a simple executive or maybe go completely

                                                                                                                    bare metal (or FPGA!).

                                                                                                                     

                                                                                                                    You can achieve 20-50usec latency or less even with (say) 16MHz clock speed ancient

                                                                                                                    CPU targetted OS's, so 100usec with Linux =  not so amazing latency figure to use as an example.

                                                                                                                     

                                                                                                                    Let's say you want to implement and test a new motor control algorithm for a

                                                                                                                    DC motor - the 100usec latency you quoted won't help, wherease 20usec becomes actually quite useful.

                                                                                                                    This is hardly an exotic example that I have chosen.

                                                                                                                    • 56. Re: Pi vs BeagleBone-Black
                                                                                                                      michaelkellett

                                                                                                                      I'll chip in my 2p worth at this point - I think the PRU is better imagined as a cross between DMA and a co-processor - it's much more tightly linked to the ARM core than an external processor could ever be and it's quite possible to imagine latency (if that's the right word with PRUs) down in the 10s of nS - ie two or three orders faster than a real time Linux or similar OS.

                                                                                                                       

                                                                                                                      The reason there are two is that you don't really expect them to multi task.

                                                                                                                       

                                                                                                                      I am a bit worried that TI are having cold feet about supporting user coding of the PRU - but I'm hoping that they'll stick with it because it seems me to offer quite a lot of the benefit of Xilinx's Xynq architecture but with a much easier entry.

                                                                                                                       

                                                                                                                      MK

                                                                                                                      • 57. Re: Pi vs BeagleBone-Black
                                                                                                                        shabaz

                                                                                                                        I think it also saves the requirement to have external FPGA + RAM for many non-critical use-cases. For example, it may now be possible to read in (say) a small array CCD using just the single chip (analog circuitry aside), rather than  an FPGA/CPLD as in the past. That's something I'm planning to do with the board. Same with other types of data aquisition where Linux doesn't cut it.

                                                                                                                        • 58. Re: Pi vs BeagleBone-Black
                                                                                                                          gdstew

                                                                                                                          shabaz wrote:

                                                                                                                           

                                                                                                                          "100 uS will work for a wide range of real time applications"

                                                                                                                           

                                                                                                                          In many cases, perhaps you really should be looking at additional

                                                                                                                          hardware to offload this and if required, a simple executive or maybe go completely

                                                                                                                          bare metal (or FPGA!).

                                                                                                                           

                                                                                                                          You can achieve 20-50usec latency or less even with (say) 16MHz clock speed ancient

                                                                                                                          CPU targetted OS's, so 100usec with Linux =  not so amazing latency figure to use as an example.

                                                                                                                           

                                                                                                                          Let's say you want to implement and test a new motor control algorithm for a

                                                                                                                          DC motor - the 100usec latency you quoted won't help, wherease 20usec becomes actually quite useful.

                                                                                                                          This is hardly an exotic example that I have chosen.

                                                                                                                          In many cases, perhaps you really should be looking at additional

                                                                                                                          hardware to offload this and if required, a simple executive or maybe go completely

                                                                                                                          bare metal (or FPGA!).

                                                                                                                           

                                                                                                                          Again, thanks for pointing out the obvious.

                                                                                                                           

                                                                                                                          You can achieve 20-50usec latency or less even with (say) 16MHz clock speed ancient

                                                                                                                          CPU targetted OS's, so 100usec with Linux =  not so amazing latency figure to use as an example.

                                                                                                                           

                                                                                                                          I'd have to see a (say) real example of this because as far as I can tell you are (say) just guessing. I doubt that the (say) 16 MHz processor  would

                                                                                                                          be capable of running more than a couple of very simple tasks and certainly not enough for the motor control application you speak of and still manage

                                                                                                                          the 20 - 50 uS latency requirement. There is more to real time than just latency requirements, you have to be able to get the work done in time especially

                                                                                                                          if you are talking about hard real time. The only reason I bring this up is because you keep throwing straw men at me and I don't have time to respond to

                                                                                                                          endless "what ifs" from you. You  use the tool that is appropriate for what you want to do but some people on this forum do not know enough about real

                                                                                                                          time Linux to know how able it is (or is not) to do what they want to do. I am trying to nudge them into exploring this for themselves, not argue with

                                                                                                                          someone about the finer points of what is or is not needed for any particular RTOS application.

                                                                                                                           

                                                                                                                          Nobody said anything about amazing, quit putting words in my mouth.

                                                                                                                           

                                                                                                                          Let's say you want to implement and test a new motor control algorithm for a

                                                                                                                          DC motor - the 100usec latency you quoted won't help, wherease 20usec becomes actually quite useful.

                                                                                                                          This is hardly an exotic example that I have chosen.

                                                                                                                           

                                                                                                                          Completely depends on the speed of the motor which also falls into "very application dependent". In fact there are real world applications

                                                                                                                          where real time Linux is used for motor control so you're right its not very exotic, or very useful as an example.

                                                                                                                           

                                                                                                                          Again, and for the last time I would be very surprised if the number of real time applications needing 20-50 uS latency is not greatly outnumbered

                                                                                                                          by the applications that don't. If you do not need ultra rapid response, and you do need a full fledged POSIX compliant real time API and have the

                                                                                                                          resources to support or need more than just a bare bones RTOS then real time Linux is something you should look into.

                                                                                                                           

                                                                                                                          Got it ?

                                                                                                                          • 59. Re: Pi vs BeagleBone-Black
                                                                                                                            John Beetem

                                                                                                                            Luc Cool wrote:

                                                                                                                             

                                                                                                                            I agree upon the idea of a bare metal microcontroller for real time behavour.

                                                                                                                            Programming in assembly however doesn't seem an efficient way of doing things.

                                                                                                                            It's like almost 10 years ago I used assembly, and only to create small procedures that were called from C.

                                                                                                                            On the other hand, it will limit your design to just the beagle boards.

                                                                                                                            Most modern microcontrollors already contain the glue logic for an usb or spi interface.

                                                                                                                            Not needing extra hardware will reduce the hardware price of your design, but the development effort and time will be bigger.

                                                                                                                            My understanding of PRUSS is that it's very much like the hidden RISC processor in Freescale's (formerly Motorola's) QUICC SoCs.  QUICC implements serial protocols such as HDLC, Async HDLC, and ATM using either ROM microcode or downloadable microcode.  The huge difference is that PRUSS is an open architecture so you can program it for whatever you want (within its memory limitiations) rather than depending on "binary blobs".  While I haven't looked closely at PRUSS, it may be that it's hard to write a C compiler that would use it efficiently.  Or it may simply be that given the number of actual PRUSS programmers it's not worth the effort because the compiler would be too expensive.  This was the case for a long time with TI DSPs.  I once did an image processing application for a TMS320C40 and by extreme cleverness got a factor of 6 improvement over the C compiler by rewriting the compiler-generated ASM.  I don't know how well they do now, but each time pipelines get longer it gets harder for a compiler to do an optimal job.

                                                                                                                            • 60. Re: Pi vs BeagleBone-Black
                                                                                                                              gdstew

                                                                                                                              Michael Kellett wrote:

                                                                                                                               

                                                                                                                              I'll chip in my 2p worth at this point - I think the PRU is better imagined as a cross between DMA and a co-processor - it's much more tightly linked to the ARM core than an external processor could ever be and it's quite possible to imagine latency (if that's the right word with PRUs) down in the 10s of nS - ie two or three orders faster than a real time Linux or similar OS.

                                                                                                                               

                                                                                                                              The reason there are two is that you don't really expect them to multi task.

                                                                                                                               

                                                                                                                              I am a bit worried that TI are having cold feet about supporting user coding of the PRU - but I'm hoping that they'll stick with it because it seems me to offer quite a lot of the benefit of Xilinx's Xynq architecture but with a much easier entry.

                                                                                                                               

                                                                                                                              MK

                                                                                                                               

                                                                                                                              The main purpose of the PRUs is to provide support for industrial real time communications protocols. Luckily they decided not to limit them to that purpose. On the BB Black I count about

                                                                                                                              15 I/O pins (really hard to be sure due to the massive multiplexing of some of the chips I/O pins) that are connected to the PRUs and available on BB Black connectors. As always the number

                                                                                                                              actually available for use depends on what other things you are using the I/O for. As an example you will lose 8 - 12 of them if you want to use the 16 bit LCD interface. And there is only one

                                                                                                                              group of 8 sequential bits available which also happen to be in that 16 bit LCD interface.

                                                                                                                               

                                                                                                                              On the software side I am also worried about software support from TI. They have said that they would release the assembler for public use at the end of this month, but they have already put

                                                                                                                              it off once before. I would also like to know if there are any assembly library functions to implement at least a rudimentary RTOS API available for use by the public. Given the status of the

                                                                                                                              assembler itself at this time I assume the answer is no.

                                                                                                                              • 61. Re: Pi vs BeagleBone-Black
                                                                                                                                gdstew

                                                                                                                                Robert Olson wrote:

                                                                                                                                 

                                                                                                                                Do you have a recommendation for a real-time linux that works on the Pi?

                                                                                                                                 

                                                                                                                                At this time I do not know of any real-time distributions specifically made for the Raspberry Pi which somewhat surprises me. I have just begun to contemplate building one myself but I do not

                                                                                                                                know if or where I will find the time. First I need to check out http://www.xenomai.org to see how much effort it will take. I do know that real-time versions of Linux exists for ARM processors.

                                                                                                                                • 62. Re: Pi vs BeagleBone-Black
                                                                                                                                  John Beetem

                                                                                                                                  Gary Stewart wrote:

                                                                                                                                   

                                                                                                                                  The main purpose of the PRUs is to provide support for industrial real time communications protocols. Luckily they decided not to limit them to that purpose.

                                                                                                                                   

                                                                                                                                  ...

                                                                                                                                   

                                                                                                                                  I would also like to know if there are any assembly library functions to implement at least a rudimentary RTOS API available for use by the public. Given the status of the

                                                                                                                                  assembler itself at this time I assume the answer is no.

                                                                                                                                  I don't know how much RTOS you can fit into a PRU Core, which has only 8KB of program memory (2K instructions).

                                                                                                                                   

                                                                                                                                  You're right about the comm protocols.  An obvious application for PRUSS is some of the strange SCADA protocols used by some legacy units -- things like async with 32-bit words.  It's a PITA to implement some of these protocols in the main CPU, so PRUSS is a very attractive way to do it.

                                                                                                                                  • 63. Re: Pi vs BeagleBone-Black
                                                                                                                                    obcd

                                                                                                                                    Engineering is about making decisions. If you intend to make 10000+ pieces of something, real time linux might be the way to go as it will reduce hardware and manufacturing costs. If you only need to make 5, the extra time you will need to learn about real time linux and it's possibilities divided by 5 likely will make your product more expensive. If I have experience with a microcontroller and if I already have tested libraries to make it do several tasks, I will likely develop faster using that instead of a PRU or a real time kernel.

                                                                                                                                    If for wathever reason the system will reboot, my microcontroller will be on track again within a second while my real time embedded linux will need 15 seconds to reboot. Every situation is different and therefore has a different approach which is best.

                                                                                                                                    So, an attendfull reader might have noticed that I have more designs that fall in the range 5 or less than I have designs that will be produced 1000+

                                                                                                                                    • 64. Re: Pi vs BeagleBone-Black
                                                                                                                                      gdstew

                                                                                                                                      John Beetem wrote:

                                                                                                                                       

                                                                                                                                      Gary Stewart wrote:

                                                                                                                                       

                                                                                                                                      The main purpose of the PRUs is to provide support for industrial real time communications protocols. Luckily they decided not to limit them to that purpose.

                                                                                                                                       

                                                                                                                                      ...

                                                                                                                                       

                                                                                                                                      I would also like to know if there are any assembly library functions to implement at least a rudimentary RTOS API available for use by the public. Given the status of the

                                                                                                                                      assembler itself at this time I assume the answer is no.

                                                                                                                                      I don't know how much RTOS you can fit into a PRU Core, which has only 8KB of program memory (2K instructions).

                                                                                                                                       

                                                                                                                                      You're right about the comm protocols.  An obvious application for PRUSS is some of the strange SCADA protocols used by some legacy units -- things like async with 32-bit words.  It's a PITA to implement some of these protocols in the main CPU, so PRUSS is a very attractive way to do it.

                                                                                                                                       

                                                                                                                                      I don't know how much RTOS you can fit into a PRU Core, which has only 8KB of program memory (2K instructions).

                                                                                                                                       

                                                                                                                                      Yea, I know. I was hoping that would be covered under rudimentary. How about very rudimentary ? They have to use something for the communications processing to handle the

                                                                                                                                      real time aspects but you're right it can't be much.

                                                                                                                                      • 65. Re: Pi vs BeagleBone-Black
                                                                                                                                        gdstew

                                                                                                                                        Luc Cool wrote:

                                                                                                                                         

                                                                                                                                        Engineering is about making decisions. If you intend to make 10000+ pieces of something, real time linux might be the way to go as it will reduce hardware and manufacturing costs. If you only need to make 5, the extra time you will need to learn about real time linux and it's possibilities divided by 5 likely will make your product more expensive. If I have experience with a microcontroller and if I already have tested libraries to make it do several tasks, I will likely develop faster using that instead of a PRU or a real time kernel.

                                                                                                                                        If for wathever reason the system will reboot, my microcontroller will be on track again within a second while my real time embedded linux will need 15 seconds to reboot. Every situation is different and therefore has a different approach which is best.

                                                                                                                                        So, an attendfull reader might have noticed that I have more designs that fall in the range 5 or less than I have designs that will be produced 1000+

                                                                                                                                         

                                                                                                                                        I have already explained my position on this. However, just in case the short version is if you need a full fledged RTOS, you need a full fledged RTOS. If you

                                                                                                                                        need a bare bones RTOS, you need a bare bone RTOS. If you don't need and RTOS, well I think you get the point.

                                                                                                                                         

                                                                                                                                        The 10000+ is a totally arbitrary number, I'm sure there are smaller ones that it would also work well with. Your 1000+ number is probably one of the larger

                                                                                                                                        ones.

                                                                                                                                         

                                                                                                                                        The POSIX real time API is fairly common for free and commercial RTOS's so it would not be a Linux only learning experience and that may make it more

                                                                                                                                        worth the effort (just in case the day comes when you do need and RTOS).

                                                                                                                                         

                                                                                                                                        But if the PRU is already there and it will do the job why not make use of the resources you have instead of adding on parts and cost to every board you

                                                                                                                                        sell.

                                                                                                                                         

                                                                                                                                        There are several versions of Linux that boot in well under 5 seconds (1.2 sec. on embedded hardware is the fastest one I know of).

                                                                                                                                        • 66. Re: Pi vs BeagleBone-Black
                                                                                                                                          obcd

                                                                                                                                          Using the PRU will limit your design to just one family of SOC's.

                                                                                                                                          If tomorrow a new SOC comes out with twice the speed for half the price of the TI chip, you won't be able to use it.

                                                                                                                                          Fine tuning Linux boot behavor to decrease startup times is again a very time consuming and fustrating job.

                                                                                                                                          Yes, 10000+ is a totally arbitrary number, but if the knowledge how to use a real time linux or posix kernel isn't available, it's hard to predict how long it will take to create a design with that technology, and I rather play on safe and avoid the risk.

                                                                                                                                          We probably both are right in our descisions based upon the products we create.

                                                                                                                                          • 67. Re: Pi vs BeagleBone-Black
                                                                                                                                            morgaine

                                                                                                                                            Gary Stewart wrote:

                                                                                                                                             

                                                                                                                                            You really need to get better acquainted with real time Linux.

                                                                                                                                             

                                                                                                                                            And you really need to stop attacking other forum members with personal remarks like this that don't advance the argument. Focus on the message, not the person delivering it.

                                                                                                                                            • 68. Re: Pi vs BeagleBone-Black
                                                                                                                                              morgaine

                                                                                                                                              shabaz wrote:

                                                                                                                                               

                                                                                                                                              You can achieve 20-50usec latency or less even with (say) 16MHz clock speed ancient

                                                                                                                                              CPU targetted OS's, so 100usec with Linux =  not so amazing latency figure to use as an example.

                                                                                                                                               

                                                                                                                                              Let's say you want to implement and test a new motor control algorithm for a

                                                                                                                                              DC motor - the 100usec latency you quoted won't help, wherease 20usec becomes actually quite useful.

                                                                                                                                              This is hardly an exotic example that I have chosen.

                                                                                                                                               

                                                                                                                                              I agree, 100us is pretty poor response latency for most realtime requirements, and the jitter isn't even quantified.

                                                                                                                                               

                                                                                                                                              Here's an interesting quantitive study comparing the performance of ordinary SuSE with realtime SuSE.  It highlights well how the realtime version can eliminate the very bad outliers beyond 400us, yet does nothing for response jitter which is still very noisy without the outlier spikes.  It also shows how the average response latency is increased in the realtime kernel compared to the average of a normal kernel's non-outlier responses.  It's just the high latency outliers caused by scheduler task switching that the realtime kernel eliminates.

                                                                                                                                               

                                                                                                                                              Hard realtime response doesn't just seek to reduce response latency, but also its jitter.  What's more, a common goal is to reduce jitter to effectively zero ("effectively zero" in this case typically meaning sub-clock period) by using edge detection on input and running a fixed set of instructions to deliver a fixed-latency response.

                                                                                                                                               

                                                                                                                                              Full operating systems can rarely achieve such high-quality realtime behavior, and realtime Linux certainly doesn't, whereas even a 50-cent microcontroller does it with ease.  The way to go is pretty clear if one's realtime application has any kind of strong realtime requirement.

                                                                                                                                               

                                                                                                                                              Morgaine.

                                                                                                                                              • 69. Re: Pi vs BeagleBone-Black

                                                                                                                                                Luc Cool wrote:

                                                                                                                                                 

                                                                                                                                                Fine tuning Linux boot behavor to decrease startup times is again a very time consuming and fustrating job.

                                                                                                                                                It's not really so bad. You just need to start with the assumption that for something embedded you really don't want a full blown desktop distro on there. Once you're happy with making that decision you can get rid of a load of crap in the startup that's simply not necessary.

                                                                                                                                                • 70. Re: Pi vs BeagleBone-Black
                                                                                                                                                  morgaine

                                                                                                                                                  Regarding startup times, it's interesting to ponder that an AM3359 could in principle be made to initialize and preload its PRUs on startup even before commencing the Linux boot process.  This would give such an embedded system a near instant-start for many interfacing applications, delaying only the higher level processing until Linux has come up fully.

                                                                                                                                                  • 71. Re: Pi vs BeagleBone-Black
                                                                                                                                                    morgaine

                                                                                                                                                    Industrial minimodule using these AM335x PRUs described in "TQMa335: The Cortex™ A8 module with PRU support", and more detail of same.

                                                                                                                                                    • 72. Re: Pi vs BeagleBone-Black
                                                                                                                                                      gdstew

                                                                                                                                                      Morgaine Dinova wrote:

                                                                                                                                                       

                                                                                                                                                      Gary Stewart wrote:

                                                                                                                                                       

                                                                                                                                                      You really need to get better acquainted with real time Linux.

                                                                                                                                                       

                                                                                                                                                      And you really need to stop attacking other forum members with personal remarks like this that don't advance the argument. Focus on the message, not the person delivering it.

                                                                                                                                                       

                                                                                                                                                      And you really need to stop attacking other forum members with personal remarks like this that don't advance the argument. Focus on the message, not the person delivering it.

                                                                                                                                                       

                                                                                                                                                      Original message:

                                                                                                                                                       

                                                                                                                                                      The Unix model of operating systems just isn't designed for realtime programming, and no matter what realtime patches you apply or which realtime scheduler you enable (I've played with both), you're never going to get anything like the low response latency and absence of jitter that you can get from the cheapest of microcontrollers.  A far better approach is therefore to combine a bare-metal micro with a *nix system, and let the latter control the former with high-level commands which the micro then executes with very tight timing constraints.

                                                                                                                                                       

                                                                                                                                                      That was an attack on the message. I can't help if you take it personally. As far as that and your far better approach goes see the remaining responses.

                                                                                                                                                       

                                                                                                                                                      I agree, 100us is pretty poor response latency for most realtime requirements, and the jitter isn't even quantified.

                                                                                                                                                       

                                                                                                                                                      It is still, and forever will be dependent on the application (of course) and there are a lot of applications where 100 uS works just fine whether you want to admit it or not. As far as

                                                                                                                                                      jitter qualification goes we are not doing a tutorial on real time we are discussing whether real time Linux works (depending on the applications of course). There are many companies

                                                                                                                                                      that find real time Linux perfect for their needs. There are a few big time RTOS companies, QNX and LynuxWorks are two that come to mind, that offer a full feature RTOS

                                                                                                                                                      approach and not your "far better approach" when is not better (depending on the application of course). There are quite a few full feature free RTOS's that do to. Perhaps you

                                                                                                                                                      should go tell all of them that they are wrong. I'm sure they would value your opinion on that subject.

                                                                                                                                                       

                                                                                                                                                      Here's an interesting quantitive study comparing the performance of ordinary SuSE with realtime SuSE.

                                                                                                                                                       

                                                                                                                                                      The study is on a real-time Linux for enterprise servers using 8 core Opterons, not a typical real time application (and with different needs than the typical real time applications),

                                                                                                                                                      not your typical real time hardware (boy is that an understatement), and certainly not typical of real time applications discussed here. Enterprise servers anyone ?

                                                                                                                                                       

                                                                                                                                                      Hard realtime response doesn't just seek to reduce response latency, but also its jitter.  What's more, a common goal is to reduce jitter to effectively zero ("effectively zero" in this case typically meaning sub-clock period) by using edge detection on input and running a fixed set of instructions to deliver a fixed-latency response.

                                                                                                                                                       

                                                                                                                                                      This was a general discussion of using real time Linux. Hard real time was mentioned but it is not the specific subject. The specific subject is people like you and others saying real time Linux doesn't work

                                                                                                                                                      despite lots of evidence that says otherwise (and taking it personally when somebody points this out, see I told you I'd get back to that). The statement about jitter in hard real time is correct. While the goal

                                                                                                                                                      is to reduce jitter to effective zero, like most goals in the real world it can not always be achieved. For the record there are commercial products that use hard real time Linux (depending on the application of

                                                                                                                                                      course) so it seems that they have tamed the jitter monster enough to make it work anyway. That's called engineering. I'm sure they would like to hear from you to set them strait on why it doesn't really work.

                                                                                                                                                       

                                                                                                                                                      Sorry about the massive redundancy but that simple statement just keeps flying over some peoples heads.

                                                                                                                                                      • 73. Re: Pi vs BeagleBone-Black
                                                                                                                                                        morgaine

                                                                                                                                                        Gary Stewart wrote:

                                                                                                                                                         

                                                                                                                                                        Original message:

                                                                                                                                                         

                                                                                                                                                        The Unix model of operating systems just isn't designed for realtime programming, and no matter what realtime patches you apply or which realtime scheduler you enable (I've played with both), you're never going to get anything like the low response latency and absence of jitter that you can get from the cheapest of microcontrollers.  A far better approach is therefore to combine a bare-metal micro with a *nix system, and let the latter control the former with high-level commands which the micro then executes with very tight timing constraints.

                                                                                                                                                         

                                                                                                                                                        That was an attack on the message. I can't help if you take it personally. As far as that and your far better approach goes see the remaining responses

                                                                                                                                                         

                                                                                                                                                        You are deliberately misreferencing.  Your personal attack was not the comment on the above, but the comment below:

                                                                                                                                                         

                                                                                                                                                        Gary Stewart wrote:

                                                                                                                                                         

                                                                                                                                                        You really need to get better acquainted with real time Linux.

                                                                                                                                                         

                                                                                                                                                        That has nothing to do with the subject matter, and everything to do with attacking the messenger.  Don't do it.

                                                                                                                                                         

                                                                                                                                                        And then because your earlier personal attack wasn't enough, you did it again:

                                                                                                                                                         

                                                                                                                                                        Gary Stewart wrote:

                                                                                                                                                         

                                                                                                                                                        Perhaps you should go tell all of them that they are wrong. I'm sure they would value your opinion on that subject.

                                                                                                                                                         

                                                                                                                                                        and again

                                                                                                                                                         

                                                                                                                                                        Gary Stewart wrote:

                                                                                                                                                         

                                                                                                                                                        I'm sure they would like to hear from you to set them strait on why it doesn't really work.

                                                                                                                                                         

                                                                                                                                                        Just stop it.  Talk about the technical topic, don't criticise fellow forum members when you reply to them, it adds nothing to the discussion.

                                                                                                                                                         

                                                                                                                                                        Your technical comments are welcome, and interesting.  If you disagree with an observation, just say you disagree and provide contrary evidence.  You don't need to attack the messenger as part of your rebuttal.  It's not a valid form of engineering discussion.

                                                                                                                                                        • 74. Re: Pi vs BeagleBone-Black
                                                                                                                                                          morgaine

                                                                                                                                                          This is in reply to the technical subject matter, which is interesting.

                                                                                                                                                           

                                                                                                                                                          Gary Stewart wrote:

                                                                                                                                                           

                                                                                                                                                                Morgaine wrote:

                                                                                                                                                           

                                                                                                                                                                I agree, 100us is pretty poor response latency for most realtime requirements, and the jitter isn't even quantified.

                                                                                                                                                           

                                                                                                                                                          It is still, and forever will be dependent on the application (of course) and there are a lot of applications where 100 uS works just fine whether you want to admit it or not. As far as

                                                                                                                                                          jitter qualification goes we are not doing a tutorial on real time we are discussing whether real time Linux works (depending on the applications of course). There are many companies

                                                                                                                                                          that find real time Linux perfect for their needs. There are a few big time RTOS companies, QNX and LynuxWorks are two that come to mind, that offer a full feature RTOS

                                                                                                                                                          approach and not your "far better approach" when is not better (depending on the application of course). There are quite a few full feature free RTOS's that do to.

                                                                                                                                                           

                                                                                                                                                          I agree, it is always dependent on the realtime requirements of an application, and a poorly performing realtime system may well be good enough for an application that has only weak realtime requirements.  There are undoubtedly many applications for which the 100us or so latency and unspecified jitter of realtime Linux is perfectly adequate, or at least acceptable.  I even use it myself for MIDI work (I use Linux for everything, realtime for MIDI musician apps), and it is on the verge of being acceptable if one isn't very demanding.  One could never call it great though, as the hand-ear-brain system easily notices the poor latency.

                                                                                                                                                           

                                                                                                                                                          We're not doing a tutorial, but we are discussing the technical merits of different approaches to achieving realtime performance in an embedded Linux system, and there is not the slightest doubt that the realtime performance of realtime Linux is very poor compared to that of any old bare metal embedded microcontroller.

                                                                                                                                                           

                                                                                                                                                          That's not in any doubt because it's not a matter of opinion but a matter of measurement.  You seem to be disputing the quantitive study that I linked because it used high-end machinery, but high-end machinery will almost always yield better performance in a realtime operating system simply because everything runs faster, so I can't agree with your dismissal of that study.  On a low-end Linux system, naturally the performance would have been even worse.

                                                                                                                                                           

                                                                                                                                                          Morgaine.

                                                                                                                                                          • 75. Re: Pi vs BeagleBone-Black
                                                                                                                                                            mcb1

                                                                                                                                                            I wonder why I gave up on the Pi forums.

                                                                                                                                                             

                                                                                                                                                            It used to be so much more peaceful here.....

                                                                                                                                                             

                                                                                                                                                             

                                                                                                                                                            Mark

                                                                                                                                                            • 76. Re: Pi vs BeagleBone-Black
                                                                                                                                                              morgaine

                                                                                                                                                              I noticed your interesting blog post about evaluating the Freescale Freedom-KL25z board

                                                                                                                                                               

                                                                                                                                                              That's a very nice little Cortex-M0+ microcontroller and a well-featured board, especially for frugal low power standalone applications.  Have you tried linking it to the Pi for I/O expansion and better realtime response?  The very low price would seem to make it quite a good companion for the Pi, and your "easy to use" comments were encouraging, inasmuch as the barrier for budding engineers to get to grips with microcontroller programming would be quite low.

                                                                                                                                                              • 77. Re: Pi vs BeagleBone-Black
                                                                                                                                                                gdstew

                                                                                                                                                                Morgaine Dinova wrote:

                                                                                                                                                                 

                                                                                                                                                                Gary Stewart wrote:

                                                                                                                                                                 

                                                                                                                                                                Original message:

                                                                                                                                                                 

                                                                                                                                                                The Unix model of operating systems just isn't designed for realtime programming, and no matter what realtime patches you apply or which realtime scheduler you enable (I've played with both), you're never going to get anything like the low response latency and absence of jitter that you can get from the cheapest of microcontrollers.  A far better approach is therefore to combine a bare-metal micro with a *nix system, and let the latter control the former with high-level commands which the micro then executes with very tight timing constraints.

                                                                                                                                                                 

                                                                                                                                                                That was an attack on the message. I can't help if you take it personally. As far as that and your far better approach goes see the remaining responses

                                                                                                                                                                 

                                                                                                                                                                You are deliberately misreferencing.  Your personal attack was not the comment on the above, but the comment below:

                                                                                                                                                                 

                                                                                                                                                                Gary Stewart wrote:

                                                                                                                                                                 

                                                                                                                                                                You really need to get better acquainted with real time Linux.

                                                                                                                                                                 

                                                                                                                                                                That has nothing to do with the subject matter, and everything to do with attacking the messenger.  Don't do it.

                                                                                                                                                                 

                                                                                                                                                                And then because your earlier personal attack wasn't enough, you did it again:

                                                                                                                                                                 

                                                                                                                                                                Gary Stewart wrote:

                                                                                                                                                                 

                                                                                                                                                                Perhaps you should go tell all of them that they are wrong. I'm sure they would value your opinion on that subject.

                                                                                                                                                                 

                                                                                                                                                                and again

                                                                                                                                                                 

                                                                                                                                                                Gary Stewart wrote:

                                                                                                                                                                 

                                                                                                                                                                I'm sure they would like to hear from you to set them strait on why it doesn't really work.

                                                                                                                                                                 

                                                                                                                                                                Just stop it.  Talk about the technical topic, don't criticise fellow forum members when you reply to them, it adds nothing to the discussion.

                                                                                                                                                                 

                                                                                                                                                                Your technical comments are welcome, and interesting.  If you disagree with an observation, just say you disagree and provide contrary evidence.  You don't need to attack the messenger as part of your rebuttal.  It's not a valid form of engineering discussion.

                                                                                                                                                                  You are deliberately misreferencing.

                                                                                                                                                                 

                                                                                                                                                                No, you are. The statement:

                                                                                                                                                                 

                                                                                                                                                                  The Unix model of operating systems just isn't designed for realtime programming, ...

                                                                                                                                                                 

                                                                                                                                                                the "attack":


                                                                                                                                                                You really need to get better acquainted with real time Linux.

                                                                                                                                                                 

                                                                                                                                                                Pretty sure that is a response to the message not an attack on the messenger and directly related to that statement, subject matter or not.

                                                                                                                                                                 

                                                                                                                                                                  Just stop it.  Talk about the technical topic, don't criticise fellow forum members when you reply to them, it adds nothing to the discussion.

                                                                                                                                                                 

                                                                                                                                                                Does your regular use of fanbois or Raspberry Pi fanbois in completely non-technical posts of yours count as criticizing fellow forum members ?

                                                                                                                                                                 

                                                                                                                                                                We're not doing a tutorial, but we are discussing the technical merits of different approaches to achieving realtime performance in an embedded Linux system, and there is not the slightest doubt that the realtime performance of realtime Linux is very poor compared to that of any old bare metal embedded microcontroller.

                                                                                                                                                                 

                                                                                                                                                                Not sure how discussing hard real time jitter relates to discussing the performance of real time Linux compared to any old bare metal processor. Seems like it would be more appropriate if we were discussing real time Linux performance verses

                                                                                                                                                                any other full feature RTOS performance (apples to apples).

                                                                                                                                                                 

                                                                                                                                                                Your technical comments are welcome, and interesting.  If you disagree with an observation, just say you disagree and provide contrary evidence.

                                                                                                                                                                 

                                                                                                                                                                I do, and you do your best to ignore it. Well until now at least.

                                                                                                                                                                 

                                                                                                                                                                I agree, it is always dependent on the realtime requirements of an application, and a poorly performing realtime system may well be good enough for an application that has only weak realtime requirements.  There are undoubtedly many applications for which the 100us or so latency and unspecified jitter of realtime Linux is perfectly adequate, or at least acceptable.

                                                                                                                                                                 

                                                                                                                                                                OK, thanks ? But excuse me if I add that the quality of the performance is in the eye of the people building the application and the performance of the application itself not what negative spin you

                                                                                                                                                                want to put on it. Your continual use of damming with faint praise, adding "poorly performing", "weak realtime requirements", and "at least acceptable" to your sentences are classic examples,

                                                                                                                                                                clearly show bias on your part. You keep using absolute terms (always negative) to describe relative qualities (for the dependent part). The poor performance you speak of is prettymuch in line

                                                                                                                                                                with most commercially available full feature RTOS's given equivalent hardware and the weak real time requirements are common to a lot of applications. I'm not sure how, technically speaking of

                                                                                                                                                                course this makes them weak and I'm sure that the commercial RTOS people would hotly dispute the description of their RTOS as poorly performing.

                                                                                                                                                                 

                                                                                                                                                                We're not doing a tutorial, but we are discussing the technical merits of different approaches to achieving realtime performance in an embedded Linux system, and there is not the slightest doubt that the realtime performance of realtime Linux is very poor compared to that of any old bare metal embedded microcontroller.

                                                                                                                                                                 

                                                                                                                                                                Not sure how discussing hard real time jitter in Linux relates to discussing the performance of real time Linux compared to any old bare metal processor. Seems like it would be more appropriate if we were

                                                                                                                                                                discussing hard real time Linux performance verses any other full fearture RTOS hard real time performance (apples to apples).

                                                                                                                                                                 

                                                                                                                                                                You seem to be disputing the quantitive study that I linked because it used high-end machinery, but high-end machinery will almost always yield better performance in a realtime operating system simply because everything runs faster, so I can't agree with your dismissal of that study.

                                                                                                                                                                 

                                                                                                                                                                No, I clearly disputed the study because it was for enterprise class servers which is not even close to a typical real time application, and it did not use hardware that was even close to typical hardware. I now add that it was not a

                                                                                                                                                                hard real time test even though you used it as an example for explaining hard real time jitter problems and the test results for one particular version of non-hard real time Linux optimised for the enterprise server environment does

                                                                                                                                                                not tell me anything about others that are optimised for more general hard real time and real time applications.

                                                                                                                                                                • 78. Re: Pi vs BeagleBone-Black
                                                                                                                                                                  obcd

                                                                                                                                                                  Systems that require hard real time behavour usually also require high reliability. If I instruct my robotarm to move to coordinate x, y, I appreciate it if he actually stops at that position all the time. One way to obtain high reliability is to keep things as simple as possible which is exactly what a separate controller approach is standing for. The more complex a design, the bigger the possibillities that it contains bugs.

                                                                                                                                                                  I know there are other cases. Nobody is saying embedded linux and posix isn't having a place on the market, but it simply isn't a swiss knife for evey real time embedded design.

                                                                                                                                                                  If we would be discussing this on a meeting, I would say "it's about time to move to the next point on the agenda. We are diverting way to far from the original topic"

                                                                                                                                                                  Maybe our real time response is simply 2 slow.

                                                                                                                                                                  • 79. Re: Pi vs BeagleBone-Black
                                                                                                                                                                    ervkosch

                                                                                                                                                                    I agree Mark.  This thread has lost focus. 

                                                                                                                                                                     

                                                                                                                                                                    It WAS about a comparison of the Raspberry Pi to BeagleBone Black and how we'll use each.  Now we have gotten down to Real Time OS and FPGA like abilities.  95% of the market is going to use BOTH boards for hobbies and prototyping.  I was one of the first people to say my preferences (RPi Model A for small stuff because of power consumption and BBB for large projects because it has more of the features I'm looking for like IO.)

                                                                                                                                                                     

                                                                                                                                                                    I would say lets fork the BBB technical talk to another thread (maybe in the BeagleBone forum) because that seems to all this is now.

                                                                                                                                                                    • 80. Re: Pi vs BeagleBone-Black
                                                                                                                                                                      mcb1

                                                                                                                                                                      Morgaine

                                                                                                                                                                       

                                                                                                                                                                      Not yet, as I'm waiting for the headers to arrive. Silly me expected jaycar to carry them, but no...

                                                                                                                                                                      I did order 3 more to go with the ione E14 sent. How could you resist.?

                                                                                                                                                                       

                                                                                                                                                                      An expansion board is lacking as well, which is a shame as the number of I/O make this better priced than a Mega.

                                                                                                                                                                      I have a cunning plan, but need to sit down and discuss it with someone for doing the boards and then selling them to make them very affordable.

                                                                                                                                                                       

                                                                                                                                                                      If you've been following the top members forum, you'll also see that currently mbed.org is my best option for programming it, and someone has kindly done half a library that allows the existing arduino sketch to be used.

                                                                                                                                                                       

                                                                                                                                                                      I've ordered another Pi interface so eventually it will get connected, or a normal arduino and this used as a remote using the built-in accelerometer and touch slider.

                                                                                                                                                                       

                                                                                                                                                                      Cheers

                                                                                                                                                                      Mark

                                                                                                                                                                      • 81. Re: Pi vs BeagleBone-Black

                                                                                                                                                                        Ervin Kosch wrote:

                                                                                                                                                                          I was one of the first people to say my preferences (RPi Model A for small stuff because of power consumption and BBB for large projects because it has more of the features I'm looking for like IO.)

                                                                                                                                                                        I'm curious what your power consumption figures are like for the model A as the BBB SRM has some interesting power consumption figures that on paper appear a good deal better than the B under somewhat similar circumstances.

                                                                                                                                                                        • 82. Re: Pi vs BeagleBone-Black
                                                                                                                                                                          mcb1

                                                                                                                                                                          Ervin

                                                                                                                                                                          I'm all up for a good debate, however this (from an outsiders view point) has turned into something else, resembling kids squabbling over he said, she said.

                                                                                                                                                                           

                                                                                                                                                                          I think everyone needs to take a deep breath, and quieten down.

                                                                                                                                                                           

                                                                                                                                                                          I've seen a written sentence interperated different ways by different readers before, and neither reader got it right, because that wasn't the way it was intended.

                                                                                                                                                                          It just so happened that the writer hadn't phrased it as well, hence it wasn't as clear as they intended.

                                                                                                                                                                           

                                                                                                                                                                           

                                                                                                                                                                          I'm sure both boards will have their place in our world, and one might be favoured over the other for xyz reason(s).

                                                                                                                                                                           

                                                                                                                                                                          I haven't seen a direct comparison between the both to enable a begineer to make choices.

                                                                                                                                                                          I'm sure that with all the intellect in this group, we should be able to draw up a chart, so that someone could do that, and yes price may be one factor.

                                                                                                                                                                           

                                                                                                                                                                          So how about it people?

                                                                                                                                                                           

                                                                                                                                                                          cheers

                                                                                                                                                                          Mark

                                                                                                                                                                          • 83. Re: Pi vs BeagleBone-Black
                                                                                                                                                                            shabaz

                                                                                                                                                                            Incidently, (just to have some concrete references for anyone curious to explore that path, although I agree it's a slight digression now, not really discussing the beagleboard specifically), there are some RTOSs that have so-called 'low' latency, even the extremely common uC/OS (I think the code is free - otherwise is available with the author's book) manages tens of usec with (say) a 16MHz clock. Probably nothing stopping people from porting it to this processor, although I'm personally not interested. Another commercial example is EOS (a very old operating system developed by Etnoteam, Italy. It is multitasking and can support real time applications. Versions were available for the Intel 8086 and old Motorola devices. The basic version occupies approximately 4kbytes of ROM, but this rises to tens of kb for the complete system.It was modular and was intended for a variety of applications). I found this report of its performance on an ancient ARMv3 running at 25MHz (scheduling/context switch time is fairly low). But, even tens of usec is useless for many tasks like the robot arm example.

                                                                                                                                                                            eos.jpg

                                                                                                                                                                             

                                                                                                                                                                            There were other RTOSs with this ballpark of latency. Another example is Hitachi's HI8 which achieved good results on another ancient processor (H8/500 series, this is from late 1980s, so very old (one can assume the CPU speed was below 16MHz):

                                                                                                                                                                            hi8.jpg

                                                                                                                                                                            Also, agree POSIX compliance is not always required, and is not relevant to small processors like the one on the beagleboard, where you want to write some tight code anyway. For example, Japan had it's own standards for smaller processors. It is generally accepted that some form of process synchronization is needed, scheduling methods, memory management and so on, but all the systems mentioned above implemented these features. POSIX is not always necessary because one may never want to port to another device, or, more commonly, people don't directly use the APIs anyway because often, some higher-level framework is created to abstract away from the raw API, to protect oneself, or to have object-oriented framework possibly, and write better code too.

                                                                                                                                                                             

                                                                                                                                                                            It's a digression, but useful to know about the choices for the small processors.

                                                                                                                                                                             

                                                                                                                                                                            Having said all that, if I wanted to interface to any hardware (most hardware) that requires reasonable timing, I too wouldn't be interested in running Linux nor any OS for high/average-speed tasks (coding with interrupts is perfect for many use-cases), nor real-time Linux; I would use Linux for tasks that I don't mind to have more latency (e.g. UI update) or where it's too hard to re-write vast libraries of code that already exists on Linux.

                                                                                                                                                                             

                                                                                                                                                                            So, for me, I'm looking forward to trying the board, because I don't like bringing out ISE and having to prototype a board just to have some (averagely)high-speed processing going on with external hardware.

                                                                                                                                                                            • 84. Re: Pi vs BeagleBone-Black

                                                                                                                                                                              Mark,

                                                                                                                                                                              > I haven't seen a direct comparison between the both to enable a begineer to make choices.

                                                                                                                                                                               

                                                                                                                                                                              There is a summary comparison for beginners here:

                                                                                                                                                                                 http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=41489&start=81

                                                                                                                                                                               

                                                                                                                                                                              I found user gyeben's response interesting, which says:

                                                                                                                                                                               

                                                                                                                                                                                   "Took a look at the article mentioned in the first post (http://roboteurs.com/beaglebone-black-vs-raspberry-pi/) and that article is clearly unfair to the Pi. 

                                                                                                                                                                                      | Some people have clocked the Pi up to 1Ghz but its pretty risky.

                                                                                                                                                                                   It's NOT risky. Overclocking the CPU is not risky at all."

                                                                                                                                                                              • 85. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                John Beetem

                                                                                                                                                                                Mark Beckett wrote:

                                                                                                                                                                                 

                                                                                                                                                                                I'm all up for a good debate, however this (from an outsiders view point) has turned into something else, resembling kids squabbling over he said, she said.

                                                                                                                                                                                 

                                                                                                                                                                                I think everyone needs to take a deep breath, and quieten down.

                                                                                                                                                                                 

                                                                                                                                                                                ...

                                                                                                                                                                                 

                                                                                                                                                                                cheers

                                                                                                                                                                                Mark

                                                                                                                                                                                The following comment is to be taken humorously and with hopes that this shadow hasn't offended:  It does seem to the casual observer that some of the above discussion appears to be arguing-for-the-sake-of-arguing rather than a productive exchange of ideas.  Personally, some of it calls to mind a Shakespeare play in which a young man and a young woman are constantly sniping at each other through the first few acts but then they realize that all the arguing is really because of repressed sexual tension and that they're really in love with each other and become an item at the end.

                                                                                                                                                                                 

                                                                                                                                                                                Hmm, now what was the name of that play?

                                                                                                                                                                                • 86. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                  John Beetem

                                                                                                                                                                                  coder27 wrote:

                                                                                                                                                                                   

                                                                                                                                                                                  Mark,

                                                                                                                                                                                  > I haven't seen a direct comparison between the both to enable a begineer to make choices.

                                                                                                                                                                                   

                                                                                                                                                                                  There is a summary comparison for beginners here:

                                                                                                                                                                                     http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=41489&start=81

                                                                                                                                                                                   

                                                                                                                                                                                  I found user gyeben's response interesting, which says:

                                                                                                                                                                                   

                                                                                                                                                                                       "Took a look at the article mentioned in the first post (http://roboteurs.com/beaglebone-black-vs-raspberry-pi/) and that article is clearly unfair to the Pi. 

                                                                                                                                                                                          | Some people have clocked the Pi up to 1Ghz but its pretty risky.

                                                                                                                                                                                       It's NOT risky. Overclocking the CPU is not risky at all."

                                                                                                                                                                                  Here's what I wrote at in the same RasPi forum discussion:

                                                                                                                                                                                  What are some of the things you get for that extra US$10 versus RasPi?

                                                                                                                                                                                   

                                                                                                                                                                                  Faster processor: 1 GHz Cortex-A8 versus 700 MHz ARM11.

                                                                                                                                                                                  Far more I/O pins.

                                                                                                                                                                                  Ethernet that connects directly to SoC instead of over USB.

                                                                                                                                                                                  Two RISC engines for low-level programmable I/O.

                                                                                                                                                                                  BBone white has rounded corners so it actually fits in an Altoids box.  I think BBone black is the same form factor.

                                                                                                                                                                                   

                                                                                                                                                                                  According to my observations, I would say RasPi has better community support so is a better choice for new users.  IMO Beagle has always targeted developers rather than users -- I don't know if there will be an effort to change that.  Also, it may only be my own impression.

                                                                                                                                                                                   

                                                                                                                                                                                  [Edit: Beagle does have good community support -- it just seems to me that RasPi's is better and that it's easier for a new user to get up to speed with RasPi than Beagle.  For example, it's easier with RasPi to find a recommended OS version and install it.  JMO/YMMV]

                                                                                                                                                                                  Today I would also add that BBone Black has 2GB eMMC on the board which is pre-loaded with Ångström so it boots right out of the box and is immediately useful.  BBone's Cortex A8 supports other GNU/Linux distros such as Ubuntu which haven't been ported to RasPi.  (Personally, I prefer the Debian on RasPi to Ubuntu on my x86 PC -- chacun a son goût.)

                                                                                                                                                                                   

                                                                                                                                                                                  OTOH, for video RasPi's media processor is probably better.  Like Morgaine, I have no need for it so it's not an advantage.

                                                                                                                                                                                   

                                                                                                                                                                                  Also, I wrote the above comment before discovering that beagleboard.org had just reformatted their web site and it appears now to be a lot easier to get OS distros (for example).

                                                                                                                                                                                  • 87. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                    morgaine

                                                                                                                                                                                    Luc, Mark and Ervin, I agree completely about the pointless digression into realtime Linux.  That's why I didn't respond to the latest salvo, it's clearly a non-productive argument, so I ended the interchange unilaterally.  The merits or otherwise of realtime Linux are entirely irrelevant to the discussion about BBB versus Pi.  I tried to end it through reasoned discussion, but that failed.  Sorry.

                                                                                                                                                                                     

                                                                                                                                                                                    In contrast, the BBB's PRUs are entirely relevant in the comparison, because it's a salient built-in feature of the BeagleBones and is so powerful that it has front-page bullet points on beagleboard.org's BBB page.  It's clear that they rate it highly, and not discussing it in a comparison with Pi would be remiss.

                                                                                                                                                                                     

                                                                                                                                                                                    Also, let's not forget that even Eben Upton has publicly expressed support for the idea of coupling the Pi to an Arduino.  He's an engineer, and he knows full well that the gains in interface expansion and in realtime performance are really quite enormous when you combine the two.  Even the Gertboard has a microcontroller on-board, and despite not being an RPF product, it certainly has their blessing.

                                                                                                                                                                                     

                                                                                                                                                                                    Well, because of its PRUs, the BBB requires no additional microcontroller to achieve the same kind of gains in interface expansion and realtime performance, so this enters very strongly into the comparison.  Pi can handle a small amount of interfacing without additional hardware, whereas BBB can handle a lot more.  Pi can satisfy very very weak realtime requirements with its standard kernel, whereas BBB can meet very hard realtime constraints with its standard kernel because it has a couple of PRUs that are dedicated to I/O.  For ambitious applications, that's a very big deal.

                                                                                                                                                                                     

                                                                                                                                                                                    PS. This was about one feature only, where BBB happens have superior functionality.  Both boards do of course have both pros and cons, that's very clear, and it means that there is no "best board".  There is only "best board for your particular requirements", and so the answer will vary with the person.

                                                                                                                                                                                     

                                                                                                                                                                                    Morgaine.

                                                                                                                                                                                    • 88. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                      > OTOH, for video RasPi's media processor is probably better.  Like Morgaine, I have no need for it so it's not an advantage.

                                                                                                                                                                                       

                                                                                                                                                                                      I think the details are still unclear about the BBB's usability for home theatre.

                                                                                                                                                                                      Apparently it mainly uses the cpu for mpeg decoding.  So does that mean that VLC

                                                                                                                                                                                      will be usable (unlike on the RPi where only omxplayer is hardware accelerated?)

                                                                                                                                                                                       

                                                                                                                                                                                      It seems to me it is a bit unfair comparing TI's second generation BB to the RPF's

                                                                                                                                                                                      first generation product.  The RPi's big advantage now is that it is in mass production,

                                                                                                                                                                                      but the BBB is just announced and temporarily out of stock, with no clear idea of how

                                                                                                                                                                                      fast production can be ramped.  We have yet to hear when the RPi's educational release

                                                                                                                                                                                      will be or what it will include, but release 3.0 and/or 2nd generation is said to be coming.

                                                                                                                                                                                       

                                                                                                                                                                                      I think it's noteworthy that the BBB is FCC/CE certified for sale to residential users,

                                                                                                                                                                                      but the current RPi as far as I know is not.  I think it's also noteworthy that the BBB

                                                                                                                                                                                      claims to support the Microsoft wireless 800 keyboard.  I think it's noteworthy that the

                                                                                                                                                                                      Fedora ARM folks support the BB directly, rather than indirectly through Seneca as a Remix.

                                                                                                                                                                                      • 89. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                        morgaine

                                                                                                                                                                                        coder27 wrote:

                                                                                                                                                                                         

                                                                                                                                                                                        I think the details are still unclear about the BBB's usability for home theatre.

                                                                                                                                                                                         

                                                                                                                                                                                        How welll it will perform in that role remains to be seen, but one thing is absolutely crystal clear.  It was not designed for that purpose, so if it works well as a media centre it will be as a lucky side effect of providing a working X11 desktop or Arduino UI. (*)

                                                                                                                                                                                         

                                                                                                                                                                                        I've now read about half of the BBB System Reference Manual, and they make it abundantly clear that the board was developed to support engineers, technical enthusiasts, makers, and educators+students.  Reading between the lines, and from interacting with the BB community directly, there is considerable {concern,hostility,apathy} towards those that jumped on the Pi educational bandwagon purely because they wanted a cheap media centre.  The views vary of course, but I think it's safe to say that nobody considers the BBB to be a media centre platform, even if it works.

                                                                                                                                                                                         

                                                                                                                                                                                        That area still belongs entirely to the Pi, and any competition for media centre eyeballs is unlikely to be coming from the BB stable.

                                                                                                                                                                                         

                                                                                                                                                                                        Morgaine.

                                                                                                                                                                                         

                                                                                                                                                                                        (*) PS. Lucky side effects are not impossible.  BBB has been shown running Quake 3.

                                                                                                                                                                                        • 90. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                          > if it works well as a media centre it will be as a lucky side effect of providing a working X11 desktop or Arduino UI. (*)

                                                                                                                                                                                           

                                                                                                                                                                                          Or perhaps as a lucky side effect of supporting Android with Flash and/or html5.

                                                                                                                                                                                           

                                                                                                                                                                                          The RPF actively encouraged media centre users, and I think they account for

                                                                                                                                                                                          a significant fraction of sales.  I think a lot of folks justify the purchase by saying

                                                                                                                                                                                          "I'll buy it to learn programming, and if that doesn't work out, I can still use it as a

                                                                                                                                                                                          media center."  So quite a successful sales tactic.

                                                                                                                                                                                          • 91. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                            John Beetem

                                                                                                                                                                                            Morgaine Dinova wrote:

                                                                                                                                                                                             

                                                                                                                                                                                            coder27 wrote:

                                                                                                                                                                                             

                                                                                                                                                                                            I think the details are still unclear about the BBB's usability for home theatre.

                                                                                                                                                                                             

                                                                                                                                                                                            How welll it will perform in that role remains to be seen, but one thing is absolutely crystal clear.  It was not designed for that purpose, so if it works well as a media centre it will be as a lucky side effect of providing a working X11 desktop or Arduino UI. (*)

                                                                                                                                                                                             

                                                                                                                                                                                            I've now read about half of the BBB System Reference Manual, and they make it abundantly clear that the board was developed to support engineers, technical enthusiasts, makers, and educators+students.  Reading between the lines, and from interacting with the BB community directly, there is considerable {concern,hostility,apathy} towards those that jumped on the Pi educational bandwagon purely because they wanted a cheap media centre.  The views vary of course, but I think it's safe to say that nobody considers the BBB to be a media centre platform, even if it works.

                                                                                                                                                                                             

                                                                                                                                                                                            That area still belongs entirely to the Pi, and any competition for media centre eyeballs is unlikely to be coming from the BB stable.

                                                                                                                                                                                             

                                                                                                                                                                                            Morgaine.

                                                                                                                                                                                             

                                                                                                                                                                                            (*) PS. Lucky side effects are not impossible.  BBB has been shown running Quake 3.

                                                                                                                                                                                            BBone has a powerful 3D graphics engine.  I don't know how it compares to RasPi -- I hear opinions about RasPi's being better but haven't seen any independent benchmarks.  So BBone is great for synthesizing graphical images.  Now for decoding purchased (or not) video content or video encoding, it's probably true that RasPi is better, but "those frills cost money" -- you may have to purchase licenses for the RasPi Codecs.

                                                                                                                                                                                             

                                                                                                                                                                                            Regarding {concern,hostility,apathy}, my own feeling is mostly "pity" as in "here you have a pretty decent GNU/Linuix box and you just want to watch silly videos?"  My chief annoyance with "RasPi as naked Roku2" users is that they made it really hard to get a RasPi when it first came out.  OTOH, those "other users" help drive the price down, which benefits everyone in the long run.  As a free-as-in-freedom proponent, I want to be able to use hardware I buy for whatever I want so I must support the right for others to do the same.

                                                                                                                                                                                            • 92. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                              morgaine

                                                                                                                                                                                              John Beetem wrote:

                                                                                                                                                                                               

                                                                                                                                                                                              Regarding {concern,hostility,apathy}, my own feeling is mostly "pity" as in "here you have a pretty decent GNU/Linuix box and you just want to watch silly videos?"

                                                                                                                                                                                               

                                                                                                                                                                                              I haven't detected "pity", so I'll add yours to the list.

                                                                                                                                                                                               

                                                                                                                                                                                              I have noticed a fair bit of ridicule too, although I don't think any of the above 4 accounts for it.  It seems to stem from simple peergroup reinforcement, blowing raspberries at "that other lot" not for any solid reasons but to sound cool in company.  Unfortunately IRC seems to encourage it.  I think it's softened a bit now compared to 9-12 months ago, possibly because a large number of BB owners now have Pi boards too.

                                                                                                                                                                                               

                                                                                                                                                                                              I like all the boards, they all have a specific niche where they shine.  Pi-B's niche is narrowing now though.

                                                                                                                                                                                              • 93. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                John Beetem

                                                                                                                                                                                                Morgaine Dinova wrote:

                                                                                                                                                                                                 

                                                                                                                                                                                                Pi-B's niche is narrowing now though.

                                                                                                                                                                                                Indubitably.  When BBone was US$89 plus US$50 for a DVI-D card the combination was 4X a RasPi model B.  Now it's just 30% more (US$45 versus US$35).  If you're a teenager, that's a lot fewer cars to wash or lawns to mow.  Teen geeks should charge more for resetting digital clocks after power failures.

                                                                                                                                                                                                 

                                                                                                                                                                                                IMO BBone Black is the clear winner for a maker.  RasPi is IMO still better for a newbie mostly interested in software or very simple hardware.

                                                                                                                                                                                                • 94. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                  morgaine

                                                                                                                                                                                                  John Beetem wrote:

                                                                                                                                                                                                   

                                                                                                                                                                                                  When BBone was US$89 plus US$50 for a DVI-D card the combination was 4X a RasPi model B.  Now it's just 30% more (US$45 versus US$35).

                                                                                                                                                                                                   

                                                                                                                                                                                                  For the basic package prices, sure.  But these prices don't reflect the actual investment needed before you can use the boards.  For BBB you need nothing more at all if you use it tethered to a PC, because it has the O/S preloaded in the eMMC device, comes with a USB cable, and appears as a USB storage device as well as being powered through the cable.  Pull it out of the box, plug it in, it works --- instant gratification.

                                                                                                                                                                                                   

                                                                                                                                                                                                  The Pi doesn't come with any leads, and can't be used in that tethered mode, and doesn't come with an SD card anyway, so you can't use it in BBB's "minimum investment" mode.  To compare working systems fairly, you have to add to the price of the Pi a PSU (or at least a USB lead) and an SD card, and the gratification is not instant because the newbie "hurdle" of writing the SD card still has to be overcome.  Viewed that way, the Pi model B isn't cheaper than the BBB, it's either the same or more expensive, depending on the quality of accessories you buy.  For beginners, it's also a lot more hassle, and that's assuming that the  PSU and SD card that the newbie buys will actually work with the idiosyncratic little board, which is far from certain.

                                                                                                                                                                                                   

                                                                                                                                                                                                  So, I don't think that "cheaper" is actually correct for Pi unless viewed very narrowly, since it won't run as supplied.  And "easier" is debateable too.  Pi is the clear leader as a media centre.  In all other applications, it now has one direct and very able competitor, as well as a swarm of others just outside its price niche.

                                                                                                                                                                                                  • 95. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                    gdstew

                                                                                                                                                                                                    I like all the boards, they all have a specific niche where they shine.  Pi-B's niche is narrowing now though.

                                                                                                                                                                                                     

                                                                                                                                                                                                    The intended R-Pi market was always very narrowly defined (very low cost computer used to teach kids about computers). The RPF vastly underestimated its

                                                                                                                                                                                                    "geek appeal" and this is the primary reason sales took off to levels well beyond the RPFs original expectations. I don't think that will last but due to that popularity

                                                                                                                                                                                                    it has actually increased its niche to cover several other areas, using it HD video applications is probably one that it is better suited for. The  availability of a HD

                                                                                                                                                                                                    video camea will also help here. Its success and fierce competition in the SOC markets will probably create direct competitors and it will have to keep improving

                                                                                                                                                                                                    to stay ahead of them. Something I'm not sure a non-profit organization can do.

                                                                                                                                                                                                     

                                                                                                                                                                                                    The BB Black is aimed at completely different market. It is a more general purpose platform with a large number of multi-purpose I/O pins available and aimed

                                                                                                                                                                                                    primarily at computer professionals. Its more general purpose nature give it a much wider range of possible applications right from the start. There is a lot of hardware

                                                                                                                                                                                                    crossover between the two but this is true on almost every modern ARM SOCs since they almost all include a long list of the same features.

                                                                                                                                                                                                     

                                                                                                                                                                                                    From John Beetum:

                                                                                                                                                                                                     

                                                                                                                                                                                                    BBone has a powerful 3D graphics engine.  I don't know how it compares to RasPi -- I hear opinions about RasPi's being better but haven't seen any independent benchmarks.  So BBone is great for synthesizing graphical images.  Now for decoding purchased (or not) video content or video encoding, it's probably true that RasPi is better, but "those frills cost money" -- you may have to purchase licenses for the RasPi Codecs.


                                                                                                                                                                                                    It is definitely much better than the GPU in the R-Pi. The main drawback I see for the BB Black as far as video goes is the 16 bit memory data bus vs 32 bit for the Pi. Both share

                                                                                                                                                                                                    the RAM with the ARM core and the GPU, and video applications require RAM access for display as well as display data processing so it is hard to see how this would not have

                                                                                                                                                                                                    a negative impact on the BB Black in most video applications. I pretty sure the R-Pi can also play Quake Three but I'm not sure what market this helps either of them with.

                                                                                                                                                                                                     

                                                                                                                                                                                                    Does TI already have a license for the codecs ? Otherwise they would have to be bought to use them for the BB Black too.

                                                                                                                                                                                                    • 96. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                      > The intended R-Pi market was always very narrowly defined (very low cost computer used to teach kids about computers).

                                                                                                                                                                                                       

                                                                                                                                                                                                      Education was the stated goal of the RPF, but not necessarily their marketing focus prior to

                                                                                                                                                                                                      the yet-to-be-released educational release.  I see a lot more marketing effort focused on

                                                                                                                                                                                                      Maker Faire venues than educational venues.   Early on, they hired an educational person,

                                                                                                                                                                                                      but quickly let her go without a replacement until recently.

                                                                                                                                                                                                       

                                                                                                                                                                                                      > The main drawback I see for the BB Black as far as video goes is the 16 bit memory data bus vs 32 bit for the Pi.

                                                                                                                                                                                                       

                                                                                                                                                                                                      I think you also need to consider memory caches and data paths.

                                                                                                                                                                                                      On the RPi, the cpu has to go through the gpu to access memory and cache.

                                                                                                                                                                                                      I suspect the BBB has a better caching system.   There are memory benchmarks

                                                                                                                                                                                                      that might be useful, such as

                                                                                                                                                                                                       

                                                                                                                                                                                                      http://lmbench.sourceforge.net/

                                                                                                                                                                                                      • 97. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                        gdstew

                                                                                                                                                                                                        coder27 wrote:

                                                                                                                                                                                                         

                                                                                                                                                                                                        > The intended R-Pi market was always very narrowly defined (very low cost computer used to teach kids about computers).

                                                                                                                                                                                                         

                                                                                                                                                                                                        Education was the stated goal of the RPF, but not necessarily their marketing focus prior to

                                                                                                                                                                                                        the yet-to-be-released educational release.  I see a lot more marketing effort focused on

                                                                                                                                                                                                        Maker Faire venues than educational venues.   Early on, they hired an educational person,

                                                                                                                                                                                                        but quickly let her go without a replacement until recently.

                                                                                                                                                                                                         

                                                                                                                                                                                                        > The main drawback I see for the BB Black as far as video goes is the 16 bit memory data bus vs 32 bit for the Pi.

                                                                                                                                                                                                         

                                                                                                                                                                                                        I think you also need to consider memory caches and data paths.

                                                                                                                                                                                                        On the RPi, the cpu has to go through the gpu to access memory and cache.

                                                                                                                                                                                                        I suspect the BBB has a better caching system.   There are memory benchmarks

                                                                                                                                                                                                        that might be useful, such as

                                                                                                                                                                                                         

                                                                                                                                                                                                         

                                                                                                                                                                                                        The focus still seems to pretty heavy on education however given the new opportunities that opened up, things changed. I still see a heavy interest

                                                                                                                                                                                                        from the RPF in education though. They just seem to be relying more on outside help and they always said that they wanted that too.

                                                                                                                                                                                                         

                                                                                                                                                                                                        I do consider caches and data paths but I assume they both have video and CPU caches so I see no advantage either way there. Displaying video

                                                                                                                                                                                                        must have top priority otherwise the display will have artifacts and that would not do at all. For this reason it makes sense that the memory path to

                                                                                                                                                                                                        the CPU in the Pi runs through the video section first. Sooner or later (and probably fairly often) there is going to a miss in all caches and filling sets

                                                                                                                                                                                                        of tag lines (video first, always) through a 16 bit data path is a major bottleneck. Even with the 32 bit data path I'm fairly confident that this is a major

                                                                                                                                                                                                        reason as to why the Pi seems sluggish most of the time even when it is overclocked to 1 GHz. I don't see how a 16 bit data path can be made to

                                                                                                                                                                                                        improve that.

                                                                                                                                                                                                         

                                                                                                                                                                                                        I will never been a big fan of the CPU and video sharing memory on motherboards. For low cost solutions using SOC's it makes more sense but at

                                                                                                                                                                                                        a (literally) noticeable cost.

                                                                                                                                                                                                        • 98. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                          gdstew

                                                                                                                                                                                                          Morgaine wrote:

                                                                                                                                                                                                           

                                                                                                                                                                                                          and the gratification is not instant because the newbie "hurdle" of writing the SD card still has to be overcome.

                                                                                                                                                                                                           

                                                                                                                                                                                                          Every company that I know of that sells the Pi offers pre-programed SD cards too.

                                                                                                                                                                                                          • 99. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                            mcb1

                                                                                                                                                                                                            Guys/gals

                                                                                                                                                                                                             

                                                                                                                                                                                                            This is a much better debate ...well done.

                                                                                                                                                                                                            Thanks for the responses re the comparisons/features.

                                                                                                                                                                                                             

                                                                                                                                                                                                            A new user looking to compare them still has to read through lots of discussions in order to draw a list.

                                                                                                                                                                                                             

                                                                                                                                                                                                            Do we have a means of producing a table with perhaps 4 columns

                                                                                                                                                                                                            Pi A, Pi B, BB, BBB

                                                                                                                                                                                                             

                                                                                                                                                                                                            something similar to the table of Page 10 of the datasheet found here.

                                                                                                                                                                                                            (interesting it says not for dissemination)

                                                                                                                                                                                                            http://nz.element14.com/circuitco/bb-bblk-000/beaglebone-black-cortex-a8-dev/dp/2291620

                                                                                                                                                                                                             

                                                                                                                                                                                                             

                                                                                                                                                                                                            since E14 are selling both/all it shouldn't be hard to have a page that can be edited, or should we tackle a WIKI page that is maybe moderated.?

                                                                                                                                                                                                             

                                                                                                                                                                                                             

                                                                                                                                                                                                            The points made about extras are also worthy of note, and while obtaining a preprogrammed card v downloading and programming are noted, it shouldn't be beyond the realms of nearly anyone, as long as the instructions are clear (last time I looked they were).

                                                                                                                                                                                                             

                                                                                                                                                                                                            For the video discussion, that information can be included with a 'plain english' note suggesting more/less suitable as a media centre, or something that gives information to someone whom frame count and bit numbers mean nothing to.

                                                                                                                                                                                                             

                                                                                                                                                                                                             

                                                                                                                                                                                                            One thing is clear from the Pi entry into the market, it has brought change, and more affordable hardware to the reaches of more people.

                                                                                                                                                                                                            Be that technogeeks (no offense) or ordinary interested people.

                                                                                                                                                                                                             

                                                                                                                                                                                                             

                                                                                                                                                                                                            Also can someone please explain the fascination with Antoids tins.

                                                                                                                                                                                                            The KL25z apears to also fit, although I'm not sure why you'd use a metal tin to house a bare pcb that needs external connections in order to function, and generally will have a display or leds that somehow need to get through to the outside world.

                                                                                                                                                                                                             

                                                                                                                                                                                                             

                                                                                                                                                                                                            cheers

                                                                                                                                                                                                            Mark

                                                                                                                                                                                                             

                                                                                                                                                                                                            PS I will probably add a BBB to my other controllers, but in the meantime I have too many other things on to use in in anger.

                                                                                                                                                                                                            This doesn't mean that new users have the luxury and may need good information as their purchasing ability is lacking.

                                                                                                                                                                                                            • 100. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                              morgaine

                                                                                                                                                                                                              Mark Beckett wrote:

                                                                                                                                                                                                               

                                                                                                                                                                                                              The KL25z apears to also fit

                                                                                                                                                                                                               

                                                                                                                                                                                                              While it fits in the tin, it doesn't fit in the group.

                                                                                                                                                                                                               

                                                                                                                                                                                                              Just to clarify that the mention of KL25Z wasn't to rank the Freedom board alongside BB and Pi.  For the benefit of new readers ...

                                                                                                                                                                                                               

                                                                                                                                                                                                              Microcontrollers like the KL25Z/Cortex-M0+ are in a different category to application processors like the BCM2835/ARM11 or AM3359/Cortex-A8, which is why manufacturers use those two different terms as marketing slots.  ARM even formalizes the distinction in their naming now, Cortex-M (or R) series versus Cortex-A, which is much clearer than the terminology they used back in the days of ARM9 and ARM11.

                                                                                                                                                                                                               

                                                                                                                                                                                                              Boards like the Freescale Freedom KL25Z belong in the microcontroller group alongside ST's STM32F4-Discovery and the zillion forms of Arduino.  The SoCs in this group typically do not provide an MMU (at best they may provide an MPU with a small number of segments like 8), and so they cannot properly support full operating systems with strong process separation.  That's why they're nearly always programmed either as bare metal or running an RTOS designed for microcontrollers.  (The special uClinux variant can run on them, but its use has decreased markedly now that application processors are common.)

                                                                                                                                                                                                               

                                                                                                                                                                                                              Application processors have proper MMUs and so can run full Linux or other process-protected operating systems.  They're best considered separately, so your suggestion of "Pi A, Pi B, BB, BBB" is a cohesive set since they all employ application processors.

                                                                                                                                                                                                               

                                                                                                                                                                                                              Morgaine.

                                                                                                                                                                                                              • 101. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                John Beetem

                                                                                                                                                                                                                Mark Beckett wrote:

                                                                                                                                                                                                                 

                                                                                                                                                                                                                Also can someone please explain the fascination with Antoids tins.

                                                                                                                                                                                                                The KL25z apears to also fit, although I'm not sure why you'd use a metal tin to house a bare pcb that needs external connections in order to function, and generally will have a display or leds that somehow need to get through to the outside world.

                                                                                                                                                                                                                I'll have a go.  Developer boards (almost) never have cases.  This is probably because while it's very cheap to manufacture cases in quantity, the tooling for the first one is expensive.  Plus, if your target audience is makers, those makers are perfectly capable of making their own cases.  Makers like to take objects they already have and re-purpose them.  Creative use of things that would be otherwise thrown out scores Karma points, or something like that.

                                                                                                                                                                                                                 

                                                                                                                                                                                                                RasPi is frustrating because while its rectangular dimensions are the same as a credit card, its square corners prevent it from fitting in an Altoids tin.  Plus, even if you could fit it in, having connectors on five sides (if you include GPIO) makes an Altoids tin problematic.  RasPi only has two "mounting" holes (zero on the rev 1.0 board), which makes a metal case problematic.  BBone has rounded corners so it fits nicely in the case and the four mounting holes make sure you don't short to the metal case.  Having standard I/O jacks only on the ends is very nice.  OTOH, as soon as you plug in a cape it no longer fits.

                                                                                                                                                                                                                 

                                                                                                                                                                                                                I far prefer a metal case to plastic.   While EMI shouldn't be a problem with well-designed boards, plastic is a thermal insulator and I'd rather have something that conducts heat and acts as a radiator.  The RasPi model B rev 1.0 sometimes ran quite hot before rev 2.0 fixed an electrical problem and improved the thermal design for the LAN9512.  IMO rev 1.0 is not something that you want to put in a closed plastic or wood case, and rev 2.0 still generates the same amount of heat overall and would get hot in a closed case.  It will work for a while, but excessive heat shortens the lifetime of any electronic device, particularly if you thermal cycle it.

                                                                                                                                                                                                                 

                                                                                                                                                                                                                Now for BBone, one should use a YipYap box instead of Altoids.  I think they're the same size.

                                                                                                                                                                                                                • 102. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                  morgaine

                                                                                                                                                                                                                  Mark Beckett wrote:

                                                                                                                                                                                                                   

                                                                                                                                                                                                                  Also can someone please explain the fascination with Antoids tins.

                                                                                                                                                                                                                   

                                                                                                                                                                                                                  Peergroup reinforcement among techies.

                                                                                                                                                                                                                  • 103. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                    John Beetem

                                                                                                                                                                                                                    Mark Beckett wrote:

                                                                                                                                                                                                                     

                                                                                                                                                                                                                    This is a much better debate ...well done.

                                                                                                                                                                                                                    Thanks for the responses re the comparisons/features.

                                                                                                                                                                                                                     

                                                                                                                                                                                                                    A new user looking to compare them still has to read through lots of discussions in order to draw a list.

                                                                                                                                                                                                                    Epigram #48 from Epigrams in Programming by Alan J. Perlis is:

                                                                                                                                                                                                                    The best book on programming for the layman is Alice in Wonderland; but that's because it's the best book on anything for the layman.

                                                                                                                                                                                                                    Let's see what Alice's Adventures in Wonderland has to say on the topic.

                                                                                                                                                                                                                    "Cheshire Puss," [Alice] began, rather timidly... "Would you tell me, please, which way I ought to go from here?"

                                                                                                                                                                                                                     

                                                                                                                                                                                                                    "That depends a good deal on where you want to get to," said the Cat.

                                                                                                                                                                                                                     

                                                                                                                                                                                                                    "I don't much care where--" said Alice.

                                                                                                                                                                                                                     

                                                                                                                                                                                                                    "Then it doesn't matter which way you go," said the Cat.

                                                                                                                                                                                                                    Same with RasPi and BBone.  It does depend on what you want to do with it, though as Morgaine pointed out the difference has narrowed with BBone Black.

                                                                                                                                                                                                                     

                                                                                                                                                                                                                    One thing I would strongly recommend to anyone considering either board -- or any community-supported development board -- is to first spend some time at the forums available for that board.  See how active the forum is, and whether people are getting helpful responses to problems or are being told to RTFM (without providing link to said manual), or worse, "Google it" as if a newbie can tell which few of the 1000 Google results are actually useful.  If you have questions, these are the people who are going to help you -- or not.  Find out if people are having issues with the board and whether you want to face those same issues.  Also, check out the wiki for the board.  It will tell you if people are interested enough in the board to build up a good wiki and are therefore more likely to be interested in helping you when you get in trouble.

                                                                                                                                                                                                                    • 104. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                      mcb1

                                                                                                                                                                                                                      Morgaine

                                                                                                                                                                                                                      Yes thanks for explaining the KL25z wasn't part of the discussion of Pi v BB.

                                                                                                                                                                                                                      It was just the size.

                                                                                                                                                                                                                       

                                                                                                                                                                                                                      John

                                                                                                                                                                                                                      You have some good reasons ...obviously the Antoid tins are a household item on the other side of the world, hence the inital reason.

                                                                                                                                                                                                                      I also like your advice on the forums/support.

                                                                                                                                                                                                                       

                                                                                                                                                                                                                      Morgaine

                                                                                                                                                                                                                      I think your answer is probably what I expected.

                                                                                                                                                                                                                      I had to ask though.

                                                                                                                                                                                                                      • 105. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                        morgaine

                                                                                                                                                                                                                        Yay, more boards with rounded corners! And cheap too!

                                                                                                                                                                                                                         

                                                                                                                                                                                                                        Not on topic though, except for the rounded corners and the Element 14 angle.

                                                                                                                                                                                                                        • 106. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                          John Beetem

                                                                                                                                                                                                                          Morgaine Dinova wrote:

                                                                                                                                                                                                                           

                                                                                                                                                                                                                          Yay, more boards with rounded corners! And cheap too!

                                                                                                                                                                                                                           

                                                                                                                                                                                                                          Not on topic though, except for the rounded corners and the Element 14 angle.

                                                                                                                                                                                                                          I like the way the Farnell site shows availability as "Awaiting Delivery" -- sounds like we're expecting a "bundle of joy" .  The USA Newark site just says "Availability: 0" -- no poetry at all.

                                                                                                                                                                                                                          • 107. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                            morgaine

                                                                                                                                                                                                                            John Beetem wrote:

                                                                                                                                                                                                                             

                                                                                                                                                                                                                            I like the way the Farnell site shows availability as "Awaiting Delivery" -- sounds like we're expecting a "bundle of joy" .

                                                                                                                                                                                                                             

                                                                                                                                                                                                                            Better not give Marketing ideas, I really don't want to have my boards delivered with nappies and baby powder.

                                                                                                                                                                                                                            • 108. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                              mcb1

                                                                                                                                                                                                                              Here in NZ its 4 times the price of KL25z, but with less features.

                                                                                                                                                                                                                               

                                                                                                                                                                                                                              Maybe nappies and baby powder will help sell it.

                                                                                                                                                                                                                               

                                                                                                                                                                                                                              Mark

                                                                                                                                                                                                                              • 109. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                morgaine

                                                                                                                                                                                                                                Hehe.

                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                I don't know PSoC4, but a quick glance at Element 14's linked summary suggests that it's along the lines of PSoC5, which John has often described here (in CPLD/FPGA threads) as being a microcontroller SoC with partially documented programmable logic features.

                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                That makes this board rather eclectic and somewhat alienating to those who prefer traditional CPU software programming.  Perhaps the manufacturer is trying to dispell that image by releasing the board at prices that fall below the worry radar ... except in NZ, that is.

                                                                                                                                                                                                                                • 110. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                  morgaine

                                                                                                                                                                                                                                  The knode thread at http://www.element14.com/community/thread/22258?tstart=0 is interesting in the way that the community pieced together snippets of pre-release information and accidental leaks into an early picture of what BeagleBone Black would be like, even before the name was known.  And Jason Kridner's informed remarks from the horse's mouth are always interesting to read, as is his strong interest in and clarity about BB[B] openess.

                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                  Perhaps the time has come at last for BeagleBone to get its own Element 14 group, to focus discussions about these two highly compatible boards better than occasional ad hoc knode threads can provide.  Sagar's thread would make a fine initial entry, given its historical perspective.

                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                  Once BBB is in the hands of 5-figure numbers of people, I suspect there is going to be quite a feeding frenzy around it, and large numbers of related discussion threads.  Indeed, this has already begun.  Price really is king.

                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                  Morgaine.

                                                                                                                                                                                                                                  • 111. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                    shabaz

                                                                                                                                                                                                                                    It's a good idea, it will really help for collaboration. I've started reading up on the device but I ordered very late on the 22nd, so I think unfortunately I won't receive mine for a while :-(

                                                                                                                                                                                                                                    • 112. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                      jamodio

                                                                                                                                                                                                                                      For just $10 extra you get more and better hardware with added features such as analog inputs, extra GPIO, a better design power supply and you can boot from the eMMC memory on board. I've got mine early this week (got it from Mouser, Newark didn't show any stock earlier) but didn't have a chance to power it up yet, that btw to get started you can do it just via de USB device port.

                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                      I believe that for certain applications and users it will be a much better value proposition than the Raspberry Pi, and I agree that the previous Bbone was kind of pricey.

                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                      -J

                                                                                                                                                                                                                                      • 113. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                        John Beetem

                                                                                                                                                                                                                                        Morgaine Dinova wrote:

                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                        The knode thread at http://www.element14.com/community/thread/22258?tstart=0 is interesting in the way that the community pieced together snippets of pre-release information and accidental leaks into an early picture of what BeagleBone Black would be like, even before the name was known.  And Jason Kridner's informed remarks from the horse's mouth are always interesting to read, as is his strong interest in and clarity about BB[B] openess.

                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                        Perhaps the time has come at last for BeagleBone to get its own Element 14 group, to focus discussions about these two highly compatible boards better than occasional ad hoc knode threads can provide.  Sagar's thread would make a fine initial entry, given its historical perspective.

                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                        Once BBB is in the hands of 5-figure numbers of people, I suspect there is going to be quite a feeding frenzy around it, and large numbers of related discussion threads.  Indeed, this has already begun.  Price really is king.

                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                        Morgaine.

                                                                                                                                                                                                                                        The discussion you reference is in the "BeagleBone Black" group at http://www.element14.com/community/community/knode/dev_platforms_kits/element14_dev_kits/next-gen_beaglebone.  While it's buried too deep for the casual element14 user to find it, it seems at first glance to provide the same capabilities as the RasPi group.  Maybe it just needs a pointer or two so that people can find it.  There's quite a few useful and/or entertaining pages at element14 that are hiding in the file hierarchy.  If you know they exist you can find them by searching for the correct terms, otherwise it's like an Easter Egg hunt.  For example, there's a real photo of me somewhere at element14 but have fun finding it

                                                                                                                                                                                                                                        • 114. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                          John Beetem

                                                                                                                                                                                                                                          Morgaine Dinova wrote:

                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                          I don't know PSoC4, but a quick glance at Element 14's linked summary suggests that it's along the lines of PSoC5, which John has often described here (in CPLD/FPGA threads) as being a microcontroller SoC with partially documented programmable logic features.

                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                          That makes this board rather eclectic and somewhat alienating to those who prefer traditional CPU software programming.  Perhaps the manufacturer is trying to dispell that image by releasing the board at prices that fall below the worry radar ... except in NZ, that is.

                                                                                                                                                                                                                                          PSoC4 is a low-cost version of PSoC5, replacing PSoC5's Cortex-M3 with a Cortex-M0.   The PSoC line is quite interesting: Cypress integrates a processor, various digital blocks, and analog blocks all onto the same chip with a programmable interconnect to tie everything together and route to the pins.  The idea is to have a single chip provide everything for an embedded product, including the analog circuits.  The functions of the blocks and the routing are all programmed by the CPU through addressable registers, almost all of which are documented.  Cypress has a Windows-based tool called PSoC Creator that lets you select and interconnect the blocks, and it generates a C program that does the register initializations for you so you don't have to read an 1800-page manual.

                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                          My beef with the chip has been that I want to be able to use it for teaching logic design using my own tools.  Cypress almost provides enough data to do this, but as far as I can tell the routing control registers aren't documented well enough to use them.  It may be that I'm wrong and the information is now there -- please tell me if that's the case!

                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                          PSoC has had limited success, largely because the chips have been rather expensive.  PSoC4 is supposed to change this by providing a highly capable SoC for US$1.

                                                                                                                                                                                                                                          • 115. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                            morgaine

                                                                                                                                                                                                                                            John Beetem wrote:

                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                            The discussion you reference is in the "BeagleBone Black" group at http://www.element14.com/community/community/knode/dev_platforms_kits/element14_dev_kits/next-gen_beaglebone.  While it's buried too deep for the casual element14 user to find it, it seems at first glance to provide the same capabilities as the RasPi group.  Maybe it just needs a pointer or two so that people can find it.  There's quite a few useful and/or entertaining pages at element14 that are hiding in the file hierarchy.  If you know they exist you can find them by searching for the correct terms, otherwise it's like an Easter Egg hunt.

                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                            That discussion is under  "the knode > Development Platforms and Kits > element14 Development Kits > BeagleBone Black", but I think it's probably not correct to call it an Element 14 group --- you can't become a member of it.

                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                            If you look at http://www.element14.com/community/groups/ and search for a BeagleBone group or anything with "Beagle" in it, you won't find anything.  The knode holds an ad hoc mixture of discussions about development kits, and the strong cohesion you find in Element 14 Groups like this Pi one doesn't seem to be a goal there.  It's fine for low-volume discussions, but I suspect that official Element 14 groups are better for centres of community interest like Pi, Arduino, and quite probably the BeagleBone family, soon.

                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                            Time will tell.

                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                            PS. There's also the added situation that the BeagleBone community doesn't have an effective forum of its own at the moment. (There's a Google Group, but it's pretty lacklustre like they all seem to be, and you can't use it without becoming a cog in Google's targeted advertising.)  An Element 14 group would provide a useful resource that is currently  lacking, as well as as a handy group blog for description of BeagleBone projects.

                                                                                                                                                                                                                                            • 116. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                              John Beetem wrote:

                                                                                                                                                                                                                                              For example, there's a real photo of me somewhere at element14 but have fun finding it

                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                              Challenge accepted,  http://www.element14.com/community/community/members/blog/2013/04/25/having-a-blast-at-design-west

                                                                                                                                                                                                                                              • 117. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                Morgaine Dinova wrote:

                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                That discussion is under  "the knode > Development Platforms and Kits > element14 Development Kits > BeagleBone Black", but I think it's probably not correct to call it an Element 14 group --- you can't become a member of it.

                                                                                                                                                                                                                                                There's probably all sorts of interesting stuff hidden in the bowels of "the knode", the problem being that you can't find it unless you know it's there and know exactly how to get to it i.e. you have the direct link. When I try to follow the path you list, starting at the homepage, I don't see any beaglebone stuff under "element14 Development kits".

                                                                                                                                                                                                                                                Had the same problem with the Sabre-Lite area in the knode. If you try to follow the links you get re-directed to a document in a different area - with no clue there's a discussion area for it. There's been some activity - mostly me posting links to useful external info sources. but I suspect the few other posters have only found it due to something I've posted appearing near the top of the global discussions list at an opportune moment.

                                                                                                                                                                                                                                                I've also stumbled across other interesting areas from time to time, totally by accident, but it's clear that a lot of information or groups have been lost in the mists of time when you see the only two or three posts for some group were from 3-4 years ago. Is the subject just un-interesting, or is it that it's too well hidden?

                                                                                                                                                                                                                                                • 118. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                  morgaine

                                                                                                                                                                                                                                                  Hehe, yes, it is a bit ad hoc.  That's OK a lot of the time though, not every board creates a community as such.  I think it's mainly a matter of low cost and easy approachability.  Does BeagleBone Black have both?  I don't know, but the original BeagleBone may simply have been too expensive to sustain a really large and vibrant community.  BB-Black has a far greater chance, and I'm already sensing that something is stirring.

                                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                                  Maybe it's just dinner settling.

                                                                                                                                                                                                                                                  • 119. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                    Drew Fustini

                                                                                                                                                                                                                                                    I agree with you - there really isn't much of a price difference when you factor in no SD card or power supply is required.  The out of box experience is quite nice.  You simply connect the BB Black via USB cable to your computer.  It appears as a mass-storage device with a start html page.  Opening that takes you through a tutorial. 

                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                    The BB Black also creates a virtual Ethernet network over USB cable, so the HTML-based tutorial can communicate with BB Black.  Right off the bat, you can edit BoneScript (Javascript for BeagleBone) in the starter tutorial page and that code will run on the Bone. 

                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                    For a fuller experience, you can also click the link to open the Cloud9 IDE.  All that without any need for power supply, SD card, Ethernet cable, WiFi adapter or serial cable.

                                                                                                                                                                                                                                                    • 120. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                      7point62

                                                                                                                                                                                                                                                      selsinork wrote:

                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                      John Beetem wrote:

                                                                                                                                                                                                                                                      For example, there's a real photo of me somewhere at element14 but have fun finding it

                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                      Challenge accepted,  http://www.element14.com/community/community/members/blog/2013/04/25/having-a-blast-at-design-west

                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                      I'm relieved to note that John bears a passing resemblance to a 21st century Jules Verne.

                                                                                                                                                                                                                                                      • 121. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                        John Beetem

                                                                                                                                                                                                                                                        Jonathan Garrish wrote:

                                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                                        selsinork wrote:

                                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                                        John Beetem wrote:

                                                                                                                                                                                                                                                        For example, there's a real photo of me somewhere at element14 but have fun finding it

                                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                                        Challenge accepted,  http://www.element14.com/community/community/members/blog/2013/04/25/having-a-blast-at-design-west

                                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                                        I'm relieved to note that John bears a passing resemblance to a 21st century Jules Verne.

                                                                                                                                                                                                                                                        My mother says "all bearded men look alike"

                                                                                                                                                                                                                                                        • 122. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                          morgaine

                                                                                                                                                                                                                                                          I agree with you, Drew and jamodio.

                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                          Superior experience for beginners out of the box, superior experience for experts later, with far more extensive hardware interfacing potential, the programming of PRUSS, and the creation and stacking of capes.  We were talking about a simple comparison table between Pi and BBB, but I don't think that's likely to indicate just how much more advanced the BBB experience and potential really is.

                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                          The Pi is a nice little gadget if your application can work within its limits and foibles, and it has no same-price challengers yet as a home media center.  What's more, Pi Model A has no directly comparable challengers on price at all.  However, the Pi's range of "Best for application X" has now been reduced very sharply by BBB.  And somewhat embarassingly, BBB has much more education potential than Pi, and most of the Pi educational examples will work just as well or better on BeagleBones because they are typically generic Linux applications.

                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                          This is a great time to be involved with ARM, so many excellent choices.

                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                          Morgaine.

                                                                                                                                                                                                                                                          • 123. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                            morgaine

                                                                                                                                                                                                                                                            John Beetem wrote:

                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                            PSoC has had limited success, largely because the chips have been rather expensive.  PSoC4 is supposed to change this by providing a highly capable SoC for US$1.

                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                            Did you notice that the  CY8CKIT-042 PSoC4 Pioneer Kit board contains, in addition to the PSoC4 target device, a PSoC5 device that's used for board programming and debug?  (The intro video mentioned it.)  If PSoC4 is the cheap device, you'd think they'd use a second PSoC4 to provide that function on this cheap board.

                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                            It seems a little bizarre, but I guess they already had PSoC5 code developed for the required function, and don't expect to sell enough boards to recoup additional development required to use the cheaper part instead.

                                                                                                                                                                                                                                                            • 124. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                              John Beetem

                                                                                                                                                                                                                                                              Morgaine Dinova wrote:

                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                              John Beetem wrote:

                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                              PSoC has had limited success, largely because the chips have been rather expensive.  PSoC4 is supposed to change this by providing a highly capable SoC for US$1.

                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                              Did you notice that the  CY8CKIT-042 PSoC4 Pioneer Kit board contains, in addition to the PSoC4 target device, a PSoC5 device that's used for board programming and debug?  (The intro video mentioned it.)  If PSoC4 is the cheap device, you'd think they'd use a second PSoC4 to provide that function on this cheap board.

                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                              It seems a little bizarre, but I guess they already had PSoC5 code developed for the required function, and don't expect to sell enough boards to recoup additional development required to use the cheaper part instead.

                                                                                                                                                                                                                                                              Yes, I saw that.  It's not at all unusual to have a much more capable part as the program/debug interface.  If I've read the data sheets correctly, the PSoC4 only has 32KB flash and 4KB SRAM, while the PSoC5 has 256KB flash and 64KB SRAM.  It's hard to squeeze much into 32K+4KB, particularly if the code is written by people who didn't grow up carrying around boxes of punched cards (2000 cards per box * one box per arm * two arms per human = 4000 lines of code that you can "comfortably" carry around if you have two arms).

                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                              Reminds me of an LPXpresso board I have for the LPC1114FBD48/301,1LPC1114FBD48/301,1 -- a Cortex-M0 with 32KB flash and 4-8 KB RAM.  It's controlled by an LPC3154 -- an ARM9 with 192KB RAM.  I don't know how this compares to an mbed because my mbed has the controller's part number erased.

                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                              It's often the case that the control SoC is the one to play with, provided that the vendor hasn't disabled access.

                                                                                                                                                                                                                                                              • 125. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                morgaine

                                                                                                                                                                                                                                                                John Beetem wrote:

                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                Reminds me of an LPXpresso board I have for the LPC1114FBD48/301,1LPC1114FBD48/301,1 -- a Cortex-M0 with 32KB flash and 4-8 KB RAM.  It's controlled by an LPC3154 -- an ARM9 with 192KB RAM.

                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                Haha.  That's a pretty severe case of an application processor in servitude to a microcontroller.  It can't be impressed.

                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                I guess it's only a matter of time before Cortex-A series devices are given such roles too, particularly if a small realtime microcontroller needs a full-function IPv6 stack and comprehensive networking apps, and the simplest way of providing this is by giving it an entire Linux subsystem on a different SoC.

                                                                                                                                                                                                                                                                • 126. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                  John Beetem

                                                                                                                                                                                                                                                                  Morgaine Dinova wrote:

                                                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                                                  I guess it's only a matter of time before Cortex-A series devices are given such roles too, particularly if a small realtime microcontroller needs a full-function IPv6 stack and comprehensive networking apps, and the simplest way of providing this is by giving it an entire Linux subsystem on a different SoC.

                                                                                                                                                                                                                                                                  Actually, at some point it might be a good idea just to have the vendor's eval board be a BeagleBone cape.  That way they don't have to design their own controller hardware.  One problem with this is that the vendor has to worry about whether the user has a compatible operating system.  I don't have experience with Linux device drivers, but it may also be that it's a lot easier to write the whole debug controller on a bare chip than to write the Linux driver   Note that I didn't mention RasPi -- the vendor needs an open hardware project so it's not stuck if the controller board is discontinued.

                                                                                                                                                                                                                                                                  • 127. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                    gdstew

                                                                                                                                                                                                                                                                    John Beetem wrote:

                                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                                    Note that I didn't mention RasPi -- the vendor needs an open hardware project so it's not stuck if the controller board is discontinued.

                                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                                    How is any ARM SOC with a proprietary GPU considered to be open hardware ? Isn't that a contradiction of terms ?

                                                                                                                                                                                                                                                                    • 128. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                      John Beetem

                                                                                                                                                                                                                                                                      Gary Stewart wrote:

                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                      John Beetem wrote:

                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                      Note that I didn't mention RasPi -- the vendor needs an open hardware project so it's not stuck if the controller board is discontinued.

                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                      How is any ARM SOC with a proprietary GPU considered to be open hardware ? Isn't that a contradiction of terms ?

                                                                                                                                                                                                                                                                      Well, technically you're right since open source hardware (OSH) requires that all chips be fully documented.  However, my example of using BeagleBone as the controller for a chip's demo board doesn't need the GPU so for this application BeagleBone is indeed OSH.  You have open schematics, everything documented except GPU (I personally believe the PRUSS omission in latest TRM is an oversight), Gerbers, BOM, and all chips can be purchased in low volumes.  This is very different from RasPi, where most of the SoC is undocumented and it cannot be purchased in low volumes, and there are no Gerbers.

                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                      I don't know what discussion OSH advocates are having about GPUs.  I suspect some argue that if you provide a GPU + binary blob, then as long as the API interface is fully documented you can think of the GPU as an OpenGL black box that happens to be implemented with downloadable black-box microcode.  However, in that case I would say you can't call it a GPU -- it's an embedded OpenGL engine where the implementation is hidden the same way you don't expose the innards of the ARM implementation.  IMO if you call it a GPU, then you have to let me program it or it's not OSH.

                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                      I find the fact that FPGA bit streams are undocumented is much more annoying.  Yet, OSH champions like FPGAs since it lets them design their own open CPU architectures.  So plenty of opportunities to argue about how many angels can dance on the head of a pin.

                                                                                                                                                                                                                                                                      • 129. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                        John Beetem wrote:

                                                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                                                        Well, technically you're right since open source hardware (OSH) requires that all chips be fully documented.  However, my example of using BeagleBone as the controller for a chip's demo board doesn't need the GPU so for this application BeagleBone is indeed OSH. 

                                                                                                                                                                                                                                                                        There's no argument that GPU's are a problem and are likely to remain locked up behind a wall of patents, cross licensing and whatnot. So regardless of other issues the Pi isn't on the same playing field here. Most other SoCs are an Arm core with an undocumented, propriatary, GPU along for the ride, you can ignore the GPU, probably even turn it off and still use the rest of the SoC. For the Pi, you have an undocumented, propriatary Videocore GPU, with an Arm along for the ride - you can't get to the Arm without the GPU as the SoC is first and foremost a GPU.

                                                                                                                                                                                                                                                                        Even if the interface into that black box was fully documented it doesn't matter. A patent or licensing dispute could render you unable to legally use the GPU firmware and so unable to access the Arm.

                                                                                                                                                                                                                                                                        • 130. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                          Drew Fustini

                                                                                                                                                                                                                                                                          Another advantage for the BeagleBone Black, beyond OSHW, is that the BeagleBoard.org development community (TI employees, Linux kernel maintainers & various individuals) have been working hard to get all remaining patches accepted by the mainline.  Jason Kridner has told me that is an important goal for the project to be able to just git clone Linus's kernel and go.

                                                                                                                                                                                                                                                                          • 131. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                            gdstew

                                                                                                                                                                                                                                                                            John Beetem wrote:

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            Well, technically you're right since open source hardware (OSH) requires that all chips be fully documented.  However, my example of using BeagleBone as the controller for a chip's demo board doesn't need the GPU so for this application BeagleBone is indeed OSH.  You have open schematics, everything documented except GPU (I personally believe the PRUSS omission in latest TRM is an oversight), Gerbers, BOM, and all chips can be purchased in low volumes.  This is very different from RasPi, where most of the SoC is undocumented and it cannot be purchased in low volumes, and there are no Gerbers.

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            I'm not sure not using any particular piece of the hardware is an exemption since "technically" it is still proprietary. What if you decide to add an LCD display to the controller ? Certainly not an unusual possibility.

                                                                                                                                                                                                                                                                            As I am sure you are aware the Raspberry Pi also has schematics. I find I rarely need Gerbers. I find having schematics essential. I would prefer to have both but I can definately live without Gerbers The only parts

                                                                                                                                                                                                                                                                            of the BCM2835 that I know of that are not documented well enough to write drivers for are the GPU and the media engine (DSP?). Media engines are usually in the same boat as GPUs for the same reasons.

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            I'm not sure the AM335x can be purchased in low volumes either, got a source ?

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            Not talking about angels or pinheads, talking about proprietary hardware which can not by any definition be called open no matter which SOC it is on.

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            silsinork wrote:

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            Most other SoCs are an Arm core with an undocumented, propriatary, GPU along for the ride, you can ignore the GPU, probably even turn it off and still use the rest of the SoC. For the Pi, you have an undocumented, propriatary Videocore GPU, with an Arm along for the ride - you can't get to the Arm without the GPU as the SoC is first and foremost a GPU.

                                                                                                                                                                                                                                                                            Even if the interface into that black box was fully documented it doesn't matter. A patent or licensing dispute could render you unable to legally use the GPU firmware and so unable to access the Arm.

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            No idea what you are talking about here, you can ignore the GPU on the Pi too. The GPU by itself is useless without the ARM core, the opposite is not true. It is first and foremost an application processor that

                                                                                                                                                                                                                                                                            expects to have a GPU, but it does not require that the one it has be used. It may require that it have a bare minimum initialization but that does not appear to be a problem since several Linux distros, a BSD,

                                                                                                                                                                                                                                                                            and RiscOS have been able to do it, and it is not unusual for other hardware to require some initialization as well before the core can get down to the real business at hand.

                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                            Since the GPU is a Broadcom design a license dispute is probably not reasonable. As far as patents go any patent dispute on any SOC whether the item in question is being used or not would have exactly the

                                                                                                                                                                                                                                                                            same effect since the SOC physically contains the "patent". One could never guaranty that it would not be used unless it is removed and I'm sure that it can't be removed from any devices that already exists.

                                                                                                                                                                                                                                                                            Where you go from there is up to the lawyers, judge, or jury.

                                                                                                                                                                                                                                                                            • 132. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                              Gary Stewart wrote:

                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                              No idea what you are talking about here, you can ignore the GPU on the Pi too. The GPU by itself is useless without the ARM core, the opposite is not true. It is first and foremost an application processor that

                                                                                                                                                                                                                                                                              expects to have a GPU, but it does not require that the one it has be used. It may require that it have a bare minimum initialization but that does not appear to be a problem since several Linux distros, a BSD,

                                                                                                                                                                                                                                                                              and RiscOS have been able to do it, and it is not unusual for other hardware to require some initialization as well before the core can get down to the real business at hand.

                                                                                                                                                                                                                                                                              Actually you can't ignore the GPU. This device is first and foremost a GPU, albeit a GPU that's much more programmable than most - should you have NDA access to the docs.

                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                              The GPU boots first, loads it's binary blob, the GPU then loads the kernel image, then the GPU starts the Arm. Whether it's Linux, Riscos or whatever doesn't matter, the GPU is in control.  Yes this design is unusual, that's why it's of interest, and this architectural peculiarity has been well documented.

                                                                                                                                                                                                                                                                              See   http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=290&sid=bb579b1214424657140765739307279a&start=28

                                                                                                                                                                                                                                                                              http://www.raspberrypi.org/phpBB3/viewtopic.php?f=2&t=3042#p40366

                                                                                                                                                                                                                                                                              "We have implemented a number of configuration options in a file "config.txt" on boot partition (so /boot/config.txt from linux). These are read and acted on by GPU before the ARM boots.", today, one of those options is the filename of the kernel image to boot on the Arm.

                                                                                                                                                                                                                                                                                

                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                              http://en.wikipedia.org/wiki/VideoCore note there's several Videocore devices that don't have an Arm core at all.

                                                                                                                                                                                                                                                                              Since the GPU is a Broadcom design

                                                                                                                                                                                                                                                                              It's not, it was designed by Alphamosaic.

                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                              . As far as patents go any patent dispute on any SOC whether the item in question is being used or not would have exactly the

                                                                                                                                                                                                                                                                              same effect since the SOC physically contains the "patent".

                                                                                                                                                                                                                                                                              Unless the patent is in the GPU firmware blob that you require to be able to load the kernel.

                                                                                                                                                                                                                                                                              Where you go from there is up to the lawyers, judge, or jury.

                                                                                                                                                                                                                                                                              Absolutely. And you can't guarantee that the outcome of that process will be anything sane or reasonable.

                                                                                                                                                                                                                                                                              • 133. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                gdstew

                                                                                                                                                                                                                                                                                Actually you can't ignore the GPU. This device is first and foremost a GPU, albeit a GPU that's much more programmable than most - should you have NDA access to the docs.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                Never said you could ignore it, I said you don't have to use it. No it is not first and foremost a GPU, see next respoonse.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                The GPU boots first, loads it's binary blob, the GPU then loads the kernel image, then the GPU starts the Arm.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                The fact that the GPU initializes itself first and then loads the kernel image into RAM does not really change anything I wrote. It is still useless without the ARM core, it is the ARM

                                                                                                                                                                                                                                                                                core that executes the software, not the GPU.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                It's not, it was designed by Alphamosaic.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                Broadcom bought Alphamosaic in 2004 so it has been their design for over 9 years now. Broadcom owns the IP, all of it.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                Unless the patent is in the GPU firmware blob that you require to be able to load the kernel.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                See previous response.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                Absolutely. And you can't guarantee that the outcome of that process will be anything sane or reasonable.

                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                Same applies to TI or for that matter anybody in the business of manufacturing anything.

                                                                                                                                                                                                                                                                                • 134. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                  angst7

                                                                                                                                                                                                                                                                                  Gary Stewart wrote:

                                                                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                                                                  I'm not sure the AM335x can be purchased in low volumes either, got a source ?

                                                                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                                                                  TI's product page: http://www.ti.com/product/am3359#samplebuy

                                                                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                                                                  Mouser part # 595-AM3359ZCZD72.  In stock, qty 1 pricing available.

                                                                                                                                                                                                                                                                                  AVNet part # AM3359ZCZD72.  In stock, qty 1 pricing.  (Cheaper than Mouser)

                                                                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                                                                  Others available in the US and Europe.

                                                                                                                                                                                                                                                                                  • 135. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                    Drew Fustini

                                                                                                                                                                                                                                                                                    Thanks for finding those links.  I believe Newark/Farnell/element14 offer the AM3359ZCZD72AM3359ZCZD72 in single qty too:

                                                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                                                    http://uk.farnell.com/texas-instruments/am3359zczd72/mpu-sitara-arm-cortex-a8-324nfbga/dp/2113734

                                                                                                                                                                                                                                                                                    http://www.newark.com/texas-instruments/am3359zczd72/mpu-sitara-arm-cortex-a8-324nfbga/dp/95T5478

                                                                                                                                                                                                                                                                                    http://au.element14.com/texas-instruments/am3359zczd72/mpu-sitara-arm-cortex-a8-324nfbga/dp/2113734

                                                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                                                    Jason Kridner (of TI and BeagleBoard.org) stated in the DESIGN West Open Source Hardware panel discussion that they specifically design theBeagle family to use chips that are available in low quantity.

                                                                                                                                                                                                                                                                                    • 136. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                                      s ork wrote:

                                                                                                                                                                                                                                                                                      Did you catch the table in the BBB SRM showing power consumption ?   I was very interested in the Kernel Idling Display Blank figures of 280mA @ 5v, my Pi shows ~410mA in the same condition. So something is doing a better job.

                                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                                      BBB, with external 5V supply using the barrel connector, max3232 serial adapter and 100Mb network, no capes, sdcard, or usb devices

                                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                                      ~230mA with kernel idle and ondemand cpu governor, cpu running at 300Mhz. Switch to performance governor, cpu at 1GHz, and ~300mA.

                                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                                      If anything, the figures from the SRM are worst case - I don't seem to be able to reach them without adding a good number of extras.

                                                                                                                                                                                                                                                                                      • 137. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                        morgaine

                                                                                                                                                                                                                                                                                        Maybe it's the PMIC doing an awesome job of being very efficient.  It's the same TPS65217C as used on the white BeagleBone, and the more I read about its capabilities, the more it's clear that it's quite a little star in its own right.

                                                                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                                                                        I suspect that the kernel isn't clever enough yet to control it dynamically through I2C, but in principle a board that uses this PMIC could be run very frugally when not all its subsystems need to be powered at the same time, and some parts put on standby.

                                                                                                                                                                                                                                                                                        • 138. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                                          I suspect there's several factors contributing to the better power figures. There does appear to be some communication between kernel and PMIC, as I saw a reference in some of the kernel docs that enabling pwm mode causes problems for ethernet (or was it usb, I forget) and it does appear to be used for the power button and shutdown.

                                                                                                                                                                                                                                                                                          I'm sure things will improve, it's still quite early in it's lifetime..

                                                                                                                                                                                                                                                                                          • 139. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                            gdstew

                                                                                                                                                                                                                                                                                            selsinork wrote:

                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                            I suspect there's several factors contributing to the better power figures. There does appear to be some communication between kernel and PMIC, as I saw a reference in some of the kernel docs that enabling pwm mode causes problems for ethernet (or was it usb, I forget) and it does appear to be used for the power button and shutdown.

                                                                                                                                                                                                                                                                                            I'm sure things will improve, it's still quite early in it's lifetime..

                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                            It is not clear from your description, were you using the BB Black as stand alone (using HDMI video) or tethered to a PC (not using HDMI video) ? If you were not that

                                                                                                                                                                                                                                                                                            would explain some of the difference.

                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                            Morgaine wrote:

                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                            I suspect that the kernel isn't clever enough yet to control it dynamically through I2C, ...

                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                            I'm quite sure that the kernel is clever enough since it has been handling power for years on notebooks, netbooks, smart phones, and more recently tablets. It has

                                                                                                                                                                                                                                                                                            been using the motherboard version of I2C (SMB) for years too so no problems there either. Whether the people who ported the kernel were clever enough is another

                                                                                                                                                                                                                                                                                            story but since both the Linux C and header files for using the TP65217 exits I assume they were.

                                                                                                                                                                                                                                                                                            • 140. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                                              Gary Stewart wrote:

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              It is not clear from your description, were you using the BB Black as stand alone (using HDMI video) or tethered to a PC (not using HDMI video) ? If you were not that

                                                                                                                                                                                                                                                                                              would explain some of the difference.

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              I was quite clear about what I had plugged in. Specifically so that others could duplicate the test.  Yes there will be differences, but unless both you and I have exactly the same things plugged it then the numbers can't be compared anyway. Although the SRM gives some general idea of what was connected there isn't enough detail - was their usb hub powered or not, what was the precise make and model of the thumbdrive etc.

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              So, for avoidance of doubt, here's some photos of what's connected along with the current reading. this is with the default angstrom build which uses the ondemand cpufreq scaling

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              root@beaglebone:~# cat /proc/version

                                                                                                                                                                                                                                                                                              Linux version 3.8.6 (koen@rrMBP) (gcc version 4.7.3 20130205 (prerelease) (Linaro GCC 4.7-2013.02-01) ) #1 SMP Sat Apr 13 09:10:52 CEST 2013

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              root@beaglebone:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

                                                                                                                                                                                                                                                                                              ondemand

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              root@beaglebone:~# cat /proc/cpuinfo

                                                                                                                                                                                                                                                                                              processor       : 0

                                                                                                                                                                                                                                                                                              model name      : ARMv7 Processor rev 2 (v7l)

                                                                                                                                                                                                                                                                                              BogoMIPS        : 297.40

                                                                                                                                                                                                                                                                                              Features        : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls

                                                                                                                                                                                                                                                                                              CPU implementer : 0x41

                                                                                                                                                                                                                                                                                              CPU architecture: 7

                                                                                                                                                                                                                                                                                              CPU variant     : 0x3

                                                                                                                                                                                                                                                                                              CPU part        : 0xc08

                                                                                                                                                                                                                                                                                              CPU revision    : 2

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              Hardware        : Generic AM33XX (Flattened Device Tree)

                                                                                                                                                                                                                                                                                              Revision        : 0000

                                                                                                                                                                                                                                                                                              Serial          : 0000000000000000

                                                                                                                                                                                                                                                                                               


                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              IMG_2077.JPG

                                                                                                                                                                                                                                                                                              IMG_2078.JPG

                                                                                                                                                                                                                                                                                              IMG_2079.JPG

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              Whether the people who ported the kernel were clever enough is another

                                                                                                                                                                                                                                                                                              story but since both the Linux C and header files for using the TP65217 exits I assume they were.

                                                                                                                                                                                                                                                                                              The driver exists and is in use, what it's capable of is a different question. From https://github.com/beagleboard/kernel/tree/3.9

                                                                                                                                                                                                                                                                                              • PMIC: working
                                                                                                                                                                                                                                                                                              • PMIC PWM: working, kills ethernet

                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                              so it should be clear that some of the drivers are still a work-in-progress at this point.

                                                                                                                                                                                                                                                                                              It appears that as of 3.9 their external patch set is much reduced. As they get more into the upstream kernel we can expect improvements and better integration with the existing power management.

                                                                                                                                                                                                                                                                                              • 141. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                gdstew

                                                                                                                                                                                                                                                                                                There are substantial differences in your test set up and theirs so differences in current readings are to be expected. A couple of these differences stand

                                                                                                                                                                                                                                                                                                out. Since they did not specifically say the hub was powered I assume it was not. And it makes more sense that for power testing purposes to not power

                                                                                                                                                                                                                                                                                                the hub externally. They stated that the HDMI was connected so I assume the GPU was in use. Between the two port hub, the thumb drive and the GPU

                                                                                                                                                                                                                                                                                                I'd be surprised if that didn't account for most if not all of the differences you are seeing.

                                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                                I did a little checking and with a 400 KHz I2C it would take ~ 840 uS to change all three voltages (~ 280 uS for one) due to level two password

                                                                                                                                                                                                                                                                                                protection of all three registers which have to be individually unlocked before writing to them. This definitely limits just how "dynamic" it can be.

                                                                                                                                                                                                                                                                                                Still within the limits this sets it can be used to provide a substantial power savings when used.

                                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                                I received my BeagleBoard Black yesterday and had just enough to power it up tethered and spent about an hour to check it out. Not really all that

                                                                                                                                                                                                                                                                                                impressed with the tethered mode as you can already do everything it does with a PC and the beagleboard.org URL. Didn't have enough time (or the

                                                                                                                                                                                                                                                                                                HDMI cable) to check out anything more than that. I do have an RS232 converter I could use to hook up to the serial port so I might try that today.

                                                                                                                                                                                                                                                                                                • 142. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                  pmoyle111

                                                                                                                                                                                                                                                                                                  "I'm currently viewing the pcb gerbers for the beaglebone..  Have yet to see any sign of those for the R-Pi a year later."

                                                                                                                                                                                                                                                                                                   

                                                                                                                                                                                                                                                                                                  The stated goal for Pi was to make it so it couldn't be copied. The goal for this board is a reference to copy. Of course you could use the BB as a PI was intended if you can stand the extra $10.

                                                                                                                                                                                                                                                                                                  • 143. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                    John Beetem

                                                                                                                                                                                                                                                                                                    Peter Moyle wrote:

                                                                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                                                                    "I'm currently viewing the pcb gerbers for the beaglebone..  Have yet to see any sign of those for the R-Pi a year later."

                                                                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                                                                    The stated goal for Pi was to make it so it couldn't be copied. The goal for this board is a reference to copy. Of course you could use the BB as a PI was intended if you can stand the extra $10.

                                                                                                                                                                                                                                                                                                    I don't remember ever seeing that as a "stated goal" -- do you have a link?  I think non-copyability is simply a consequence of selecting a Broadcom SoC.  The stated goal of the RasPi Foundation is to provide a really cheap computer so that children can learn to program without fearing the consequences of breaking something expensive.  RPF has always stated that they don't mind competition that furthers the same goal, although one can get a different impression from some of the comments made by RasPi admins and moderators at raspberrypi.org.

                                                                                                                                                                                                                                                                                                    • 144. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                      pmoyle111

                                                                                                                                                                                                                                                                                                      It has been a  numvber of months ago and I read so many publications and belong to so many groups that I have no idea where I read it. But it was an article that was either an interview or a feature by/of a few of the architects. In it they talked about how it came to be, a number of their goals, and other aspects such as funding. One of these goals mentioned was that they specifically didn't want it to be copied (and I am loosely paraphrasing this) and as I remember that was one of that reasons for choosing the BCOM chip.

                                                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                                                      You might google to try to find the article.

                                                                                                                                                                                                                                                                                                      • 145. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                        pmoyle111

                                                                                                                                                                                                                                                                                                        hmmm... I just had a thought that it might have been on the Register.uk. I don't often read this anymore, but I go there sometimes to reads the rumors about layoffs. When I worked for one of the big chip companies that was the place to find out things and I still have a lot of friends there.

                                                                                                                                                                                                                                                                                                        • 146. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                                                          They've actually said many times that they do plan to release the designs:

                                                                                                                                                                                                                                                                                                          https://www.element14.com/community/thread/17870

                                                                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                                                                          http://www.raspberrypi.org/archives/1090#comment-20586

                                                                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                                                                          http://www.raspberrypi.org/archives/1090#comment-20591

                                                                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                                                                          and the sticking point always seems to be that the Broadcom SoC isn't easily available. but that can only be repeated so many times before people stop believing it - and the world catches up, then overtakes.

                                                                                                                                                                                                                                                                                                          • 147. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                            morgaine

                                                                                                                                                                                                                                                                                                            It is totally incorrect to suggest that a goal of RPi was to prevent it being copied.  In fact, pretty much the opposite is true, officially at least.  Here is an excerpt from the Raspberry Pi Foundation "About" page (my bolding for emphasis):

                                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                                            Raspberry Pi Foundation wrote:

                                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                                            We don’t claim to have all the answers. We don’t think that the Raspberry Pi is a fix to all of the world’s computing issues; we do believe that we can be a catalyst. We want to see cheap, accessible, programmable computers everywhere; we actively encourage other companies to clone what we’re doing. We want to break the paradigm where without spending hundreds of pounds on a PC, families can’t use the internet. We want owning a truly personal computer to be normal for children. We think that 2012 is going to be a very exciting year.

                                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                                            The BeagleBone Black is therefore exactly what the RPi Foundation is encouraging and happy to see emerge.

                                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                                            And BBB is cheaper too (you don't need to buy an extra SD card), which RPF are undoubtedly happy to see since it reduces the barrier for youngsters even further.

                                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                                            Morgaine.

                                                                                                                                                                                                                                                                                                            • 148. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                              shabaz

                                                                                                                                                                                                                                                                                                              (Reviving an old thread!)

                                                                                                                                                                                                                                                                                                              The hwmon and ADC drivers that Zubair will work on may be helpful for predicting how long power will last before the board should shut down, since the 12-bit ADC should have sufficient resolution for detecting a small drop in supply voltage hopefully if a scaled supply voltage is used for one ADC channel.

                                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                                              I had a few minutes to experiment with battery power again today.

                                                                                                                                                                                                                                                                                                              With the Olimex battery (which takes up no additional volume, because it can fit between the header connectors, the BBB should run for at least 3.5 hours, without any efforts to reduce power consumption. The battery does charge too, despite the charge voltage setting being incorrect (it should be 4.2V, but it is 4.1V with the current build).

                                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                                              With a battery connected, today the power switch (S3) on the BBB does not shut down the board, however the software can power down ('shutdown now' works). When that happens, the power consumption drops to 20uA (this hit the resolution and accuracy limit of my multimeter though). Then, it is possible to start up the BBB again by pressing S3.

                                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                                                              So, in summary, a controlled power down to near-zero curent works today. The connection on S3 is brought out to a header too, so can be brought to ground to power up the board (so we could implement an external timer or RTC to power up the board again, so that the CPU could program itself a wakeup time).

                                                                                                                                                                                                                                                                                                              • 149. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                                                                shabaz wrote:

                                                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                                                So, in summary, a controlled power down to near-zero curent works today. The connection on S3 is brought out to a header too, so can be brought to ground to power up the board (so we could implement an external timer or RTC to power up the board again, so that the CPU could program itself a wakeup time).

                                                                                                                                                                                                                                                                                                                Could the built-in RTC be used for this ?  I see that all the power up/down logic is done via the onboard rtc driver anyway.  However as far as I can tell there's no way to add a 3v coin cell to power the onboard RTC, you seem to have to use a rechargeable battery like you're doing.

                                                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                                                I'd already planned to add an external rtc due to not really wanting to add a rechargeable battery, but then found the power up/down stuff being done by the onboard rtc which complicates stuff somewhat if you want to set the clock from the external one.

                                                                                                                                                                                                                                                                                                                • 150. Re: Pi vs BeagleBone-Black
                                                                                                                                                                                                                                                                                                                  shabaz

                                                                                                                                                                                                                                                                                                                  Ohhh I'd forgotten there was an on-board RTC. I just checked the schematic, and it looks like the VLDO1 supplies the VRTC and VIO. However, it is through a resistor to VRTC, so technically it could be possible to run a separate supply by removing the resistor.

                                                                                                                                                                                                                                                                                                                  The datasheet only has a 'max' current consumption reported (5mA!) but on a forum some people asked. The link off that forum has a much better value of 370uA at 1.8V which seems pretty good!

                                                                                                                                                                                                                                                                                                                  I'm wondering though, would a coin cell be better, or one of those supercap things? Normally I use a coin cell, but I'm wondering with the low voltage requirement, maybe a supercap may be easier (although bigger I guess). Or feed from the LiPo cell if it is needed for the application. Hard to know what to do :-( With the external RTC, I was expecting to write some script to query it via (say) I2C, and then set the time each time the board powered up. But an internal RTC is very cool if we can get it working.

                                                                                                                                                                                                                                                                                                                  • 151. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                                                                    shabaz wrote:

                                                                                                                                                                                                                                                                                                                     

                                                                                                                                                                                                                                                                                                                    With the external RTC, I was expecting to write some script to query it via (say) I2C, and then set the time each time the board powered up.

                                                                                                                                                                                                                                                                                                                    Actually, if done properly - you'll need the i2c driver and rtc driver built into the kernel along with some devicetree magic - you can have the kernel do it all for you.

                                                                                                                                                                                                                                                                                                                    There's an option in the kernel config to select which rtc is used to set the clock. It defaults to rtc0, but needing to have both the onboard rtc driver to deal with power on/off and a driver for an external rtc is what makes stuff somewhat more complex.

                                                                                                                                                                                                                                                                                                                    • 152. Re: Pi vs BeagleBone-Black

                                                                                                                                                                                                                                                                                                                      shabaz wrote:

                                                                                                                                                                                                                                                                                                                      The datasheet only has a 'max' current consumption reported (5mA!) but on a forum some people asked. The link off that forum has a much better value of 370uA at 1.8V which seems pretty good!

                                                                                                                                                                                                                                                                                                                      No, that's actually quite poor..  The cheap Microchip MCP79410 i2c rtc I've been using states 5uA standby current with the clock running.

                                                                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                                                                      1.8v battery could also be rather akward as it rules out using the usual 3v coin cell without additional circuitry - datasheet says max 1.890v recommended, absolute max ov 2.1v.  There does seem to be a lot more stuff tied into VDDS_RTC which makes it that much more difficult too.