1 2 3 Previous Next 39 Replies Latest reply: Jun 14, 2012 5:34 PM by morgaine Go to original post RSS
  • 15. Re: Combining BeagleBone and Raspberry Pi
    Drew Fustini PremierFarnell

    Ah, thanks for the google group tip - just signed up.  I can see your points, so I'll hold off for now.  I think I'd likely post in my blog about BeagleBone progress and discuss, when not related to the Pi at all, in Embedded Linux or Open Source Hardware

  • 16. Re: Combining BeagleBone and Raspberry Pi
    morgaine Level 15

    @Phil: As the engineering mantra says,

     

    • "What you don''t measure, you don't really know, even when you think you do."

     

    So my approach would be to first implement coprocessor interfaces using existing pathways, be they SPI, I2C, Ethernet or USB, then to instrument those pathways, and finally to let the numbers speak and tell us where the bottlenecks are.  Then we'll know whether there is any point in optimizing the data paths, and where.

     

    If there is a major comms bottleneck for common workloads then that's not too hard to solve with dual-ported RAM sitting at the coprocessor boundary, or more ambitiously with scatter-gather controllers on each side to avoid copying data altogether.  Not rocket science, but admittedly a lot of work.

     

    Morgaine.

  • 17. Re: Combining BeagleBone and Raspberry Pi
    morgaine Level 15

    This client-mode USB port and hub on the front-end of the BeagleBone is really an exceptional idea, makes the board amazingly flexible as I described in the opening post.

     

    It makes me wonder whether some ambitious Pi hacker could route the unconnected pins of the Pi's micro-USB power socket through level translators to the Pi's GPIO header, and bit-bang up a client-mode USB interface for the Pi.

  • 18. Re: Combining BeagleBone and Raspberry Pi
    John Beetem Level 15

    BTW, what do you think of adding a BeagleBone group?  I've wanted to post about it before but wasn't sure what was the best fit.  Embedded Linux or Open Source Hardware are probably the closest.  I have one on the way so will be posting more, and it sounds like you have some interesting ideas, too.

    I'd avoid an element14 BeagleBone group at this time... there doesn't seem to be enough of a critical mass, and Google's BeagleBoard group (which includes BeagleBone) is a good place for general Beagle questions.  I've been a member since August 2008.  Most of the software questions with BeagleBoard are also relevant to BeagleBone, and I expect a lot of members have both.

     

    I'd keep posting BeagleBone related things here with some sort of real or made-up connection to RasPi.  If somebody complains, revisit.

     

    If you're new to BeagleBone, there's an interesting and sometimes amusing thread there about competition between RasPi and Beagle: "Can TI compete with Raspberry Pi?"  Here's a link to the thread, centered at a classic joke I adapted to the RasPi availability situation.  One nasty feature of Google Groups threads: if 60 days pass without a post, the thread can no longer be updated.

  • 19. Re: Combining BeagleBone and Raspberry Pi
    John Beetem Level 15

    This client-mode USB port and hub on the front-end of the BeagleBone is really an exceptional idea, makes the board amazingly flexible as I described in the opening post.

     

    It makes me wonder whether some ambitious Pi hacker could route the unconnected pins of the Pi's micro-USB power socket through level translators to the Pi's GPIO header, and bit-bang up a client-mode USB interface for the Pi.

    Looking at the hardware alone, it seems to me that the best way for RasPi to talk to BeagleBone (or BeagleBoard) is to use one of RasPi's host ports to talk to Beagle through its USB device (or OTG) port.  With Ethernet you're going through the USB-to-Ethernet conversion in the RasPi's LAN9512.  If you use USB directly you've eliminated the middleman and can use full USB bandwidth.  (Peak USB 2.0 data rate = 480 Mb/s.  "Peak data rate is a guarantee from the manufacturer that you won't go faster than this.")

     

    The difficulty, of course, is the software.  I don't know how difficult it is to write suitable host and device USB interface code.  My 1-2 year plan includes learning how to write my own USB software, in user space code and/or bare metal embedded.  The plan does not include becoming a Linux kernel guru.

  • 20. Re: Combining BeagleBone and Raspberry Pi
    John Beetem Level 15

    Morgaine Dinova wrote:

     

    Isolating your circuit from the metal is indeed one issue, but another stems from the fact that tin is not an easily workable metal.  Radio amateurs love metal for shielding of course, but even they rarely use commercial tins because tin is so hard to work compared to aluminium, and commercial tins are always thin and flexy, and the thinness actually makes them harder to modify.  Flexible thin sheet metal is just plain annoying.

    BeagleBoard and BeagleBone have mounting holes, so you can isolate using stand-offs.  Regarding thin metal, I'm told that the best way to work it is with a very sharp awl or strong needle.  You make a series of very closely spaced pin holes and then you can break off the scrap metal.  Much more reliable than drilling.

  • 21. Re: Combining BeagleBone and Raspberry Pi
    morgaine Level 15

    @Drew: Although my earlier suggestion was roughly in line with John's on an Element 14 BeagleBone group not being particularly useful at this time, there is a small reason pointing in the other direction too.  As I'm sure others have noticed, the BeagleBoard group and IRC channel is occasionally a bit fanboiish, although not to the level of comedy of RPF.  This sometimes makes discussions a bit tense and negative when talking about other ARM manufacturers.

     

    I rather doubt that my current interest in making the Pi handle graphics for my BeagleBone would go down very well in the official Beagle places, particularly since one vocal member there may be responsible for the DVI-D cape.   So, an E14 BeagleBone group might at some time become useful as an alternative place with a more broadminded focus than the official places.

     

    For now though, since Pi is part of my picture, this discussion fits in perfectly right here, so I have no personal need for a separate forum at this time.  If others do, I think I'll be neutral, and happy either way.

     

     

    Morgaine.

  • 22. Re: Combining BeagleBone and Raspberry Pi
    morgaine Level 15

    I've mentioned "Combining BeagleBone and RaspBerry Pi" on my elinux.org wiki page and linked it to here.   Not really expecting any feedback, but you never know.

     

    The BeagleBone wiki page is in a sorry state though -- basically it was initially seeded back in January, and since then not much else has happened other than someone adding advertising.  I spent a few hours today improving it, but it could do with some extra help.   http://elinux.org/BeagleBone

     

    The Raspberry Pi wiki page in contrast is a seething cauldron of activity!  http://elinux.org/RaspberryPiBoard

     

    Morgaine.

  • 23. Re: Combining BeagleBone and Raspberry Pi
    mgburr Level 4

    @Morgaine: now you've got me thinking in another direction.  I have both in house at the moment, but was looking at ways to set them up as a cluster and possibly link them with my Renesas board that's also Linux capable.  I was looking that the PI's ability to handle the graphics, but use the power from the bbone and SH7264 to give me a little more umph for the backend.  I did the roadtest for the A3, and like the layout, but commented about the lack of video also.  Also happened to get a shot of the two side by side so people could compare the different layout asthetics. 

     

    Thanks for the idea, will have to start looking down that rabbit hole :-)

  • 24. Re: Combining BeagleBone and Raspberry Pi
    morgaine Level 15

    New item of note on the BeagleBone wiki page, a pinouts section -- http://elinux.org/BeagleBone#Expansion_Connectors

  • 25. Re: Combining BeagleBone and Raspberry Pi
    morgaine Level 15

    @Michael: I don't know that Renesas board nor the microcontroller line -- a brief look at some PDFs suggests that it's somewhat similar to an ARM Cortex-M4 like the STM32F4 and roughly the same speed too.  Its most effective application in a BeagleBone-Pi cluster would therefore probably be realtime interfacing, which is how I intend to use my STM32F4-Discovery boards.

     

    I'm really looking forward to this combination of boards.  They seem to be highly complementary, each making up for the other's deficiencies.

     

    Morgaine.

  • 26. Re: Combining BeagleBone and Raspberry Pi
    mgburr Level 4

    I just aquired the STM32L152-EVAL kit from a local rep, he's working on getting me another ST board to work with. 

     

    The SH7264 Dev board had a uClinux distro for Europe only.  I was able to get that and install it, it's not bad for a bottom end linux interface.  I was dropped into the Renesas line with the current job direction and had a chance to aquire one of the kits.  But I was thinking the same thing with it.  The inherant minuses with the chip make it a great cluster controller option, which would make more cycles available to the PI and bbone. 

     

    I hadn't looked at using the STM32 for that though, might be something else I need to look at :-) First things first, make the PI a print server for the 3d printer. :-)

  • 27. Re: Combining BeagleBone and Raspberry Pi
    morgaine Level 15

    Michael Burr wrote:

     

    First things first, make the PI a print server for the 3d printer. :-)

     

    Oh you too, huh?

     

    Sadly I got distracted by all these nice new boards and my Shapercube assembly is languishing.  I must try and give it a little more priority, especially since I'll be needing it to print cases and fittings for these boards anyway.  And the Pi should be here in 3 weeks, so lack of time will only get worse.

     

    Morgaine.

  • 28. Re: Combining BeagleBone and Raspberry Pi
    mgburr Level 4

    I posted a comment on your thread about that in the Forums at RPI.  I agree with you that it should be able to handle the communications across a network and send them to the controller.  I would like to do it so I don't have to rebuild my aging/dying desktop. :-/ 

     

    Can't see why we should be able to make a router for "SD Card" info, to take the input from ethernet, and route it out the USB, which most printers are run from.

     

    Just a thought though. 

     

    Need to get my Printrbot here and built first though ;-)

  • 29. Re: Combining BeagleBone and Raspberry Pi
    pegwag Level 1

    Morgaine & All

    I must say . . . I'm in awe of you! I am new at the Linux game and have been having a blast with getting everything working. Such a joy when it comes together. I am wondering what you have in mind with the Pi & Beagle deal. I get the graphics processing part but to what end? Sorry if that sound below your league. I'm just curious what testing or end result you've got in mind. I've dealt with PC's on an enterprise level for over 20 years and have, due to getting a Raspi, become quite smitten with the entire electronics aspect. I can see spending the next 20 years with this side of the house! I would appreciate a brief overview of what you have in mind!

    Thanks

    Peg