30 Replies Latest reply on Dec 17, 2012 11:13 PM by bheemarao

    Wanted, help finding embedded linux board

      Looking for some help finding a small embedded linux board that meets a few basic requirements.  I've been able to find some things that are close, but nothing that really fits properly and I'm hoping for some suggestions I've not seen or considered already.

       

      Current requirements are as follows.

       

      Software:

      Mainline linux kernel. I should be able to use git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git and be able to build a working kernel for the device including all critical hardware drivers without needing any external patches or vendor trees. All drivers for critical hardware must be fully functional.  I'll only consider relaxing this requirement if there's a good well organised community that are obviously actively working to merge the necessary code into the mainline kernel.

       

      Hardware:

      Arm cpu preferred, but not essential. Something roughly equivalent to a Cortex A8 or better. Would consider MIPS or other alternatives as well. Single core.

      Minimum 256MB ram available for linux. If something else on the SoC is stealing ram for it's own use then an equivalent increase in physical ram is required.

      Hardware assisted SPI controller. Bit-bang is not acceptable.

      Hardware assisted I2C controller. Bit-bang is not acceptable.

      Approx 16 interrupt capable GPIO pins. These must be in addition to the SPI/I2C, shared alternate functions with the I2C/SPI are not acceptable.

      Ethernet. Need not be fast, 10Mb/s would suffice. Native ethernet preferred, usb as a last resort.

      RS232 port.

      Boot from micro-sd card. Native sdhci controller capable of 1.8v operation with associated speed modes.

       

      All hardware interfaces need to be made available on a cheap, easy to use connector. Boards with connectors that cost a significant percentage of the base board cost are unlikely to be considered.

       

      Power budget 1-2 watts.

       

      It's acceptable for the hardware to have other included functions such as a gpu or sata controller or to exceed the base requirements, but not required. Non essential functions should not be a significant cost factor.

       

      Budget: $50 or less. Not negotiable.

       

      Available ex-stock from farnell/element14 would be very much preferred.

       

      Finally, whatever the SoC, a comprehensive datasheet needs to be publicly available. This datasheet should include all information required to write device drivers for all included hardware.

       

       

      For anyone who's been following discussions over in the Raspberry Pi area, you may have some insight to the way I've set the requirements.  Other devices that have been considered are things like BeagleBone, iMX53-QSB, OlinuXino, Odroid-X, all of which have advantages and disadvantages when measured against the list of requirements.

       

      Thanks for any suggestions you may be able to offer.

        • Re: Wanted, help finding embedded linux board
          John Beetem

          I have no idea how real it is, but I just found out about the "Cubieboard" at RasPi forum: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=62&t=11423.

           

          AllWinner A10

          HDMI 1080p output

          1 GB DDR3

          10/100 ethernet connector

          2 USB Host, 2 MMC slot, 1 Infra-red

          96 extend pin including i2c, spi, lcd, sata, sensors, ..

           

          Other links:

          http://en.wikipedia.org/wiki/Cubieboard

          http://cubieboard.org/

            • Re: Wanted, help finding embedded linux board

              The hackberry one at the start of that thread looks somewhat interesting too, but sadly lacks any gpio and so falls into the same category as the APC-IO

               

              The cubieboard looks much more along the right lines, if rather light on information for now.  Trying the 'buy' link on their site gives an odd error from paypal about not being able to decrypt a certificate. Somewhat in the same territory the R-Pi was ~9months ago then.

               

              Hard to tell from the photos, but are those two large connectors down either side 2mm pitch ?  That would be another concern on availability of those, not that I've looked but 2mm are not exactly popular. I can understand why they've used them though.

               

              Thanks John, that's two boards I hadn't seen before.

                • Re: Wanted, help finding embedded linux board
                  John Beetem

                  selsinork wrote:

                   

                  Hard to tell from the photos, but are those two large connectors down either side 2mm pitch ?  That would be another concern on availability of those, not that I've looked but 2mm are not exactly popular. I can understand why they've used them though.

                  I love 2 mm connectors.  They're almost as robust as 0.1" connectors and take up 62% of the area.  Only place they seem to have caught on in a big way is jumper blocks.  I always though it silly that Eurocard connectors use 0.1" pin pitch.  Sorry, I mean "2,54 mm".  Soft metric -- pfui.

                    • Re: Wanted, help finding embedded linux board

                      I love 2 mm connectors.  They're almost as robust as 0.1" connectors and take up 62% of the area.  Only place they seem to have caught on in a big way is jumper blocks.

                      Yeah, and look how hard it is to get 2mm jumpers

                       

                      Ultimately as long as the connectors are easily available and cheap it's not a problem. The original thing in the list of requirements was more aimed at things like this HEADER, 0.5MMHEADER, 0.5MM as found on my iMX53QSB. The cost of something like this that's tall enough to clear other things on the board becomes a significant part of a $50 board and it's far from clear if I'd be able to hand solder one, all of which adds to the eventual cost.

                  • Re: Wanted, help finding embedded linux board
                    John Beetem

                    John Beetem wrote:

                     

                    I have no idea how real it is, but I just found out about the "Cubieboard" at RasPi forum: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=62&t=11423.

                     

                    AllWinner A10

                    HDMI 1080p output

                    1 GB DDR3

                    10/100 ethernet connector

                    2 USB Host, 2 MMC slot, 1 Infra-red

                    96 extend pin including i2c, spi, lcd, sata, sensors, ..

                     

                    Other links:

                    http://en.wikipedia.org/wiki/Cubieboard

                    http://cubieboard.org/

                    According to this brief interchange http://cubieboard.org/about/, 100 CubieBetaBoards should be available 1 September.  Not clear about whether they're assembled or just PC Boards.  They have an interesting minimalist web site.  I'm looking forward to seeing how this plays out.

                      • Re: Wanted, help finding embedded linux board
                        John Beetem

                        John Beetem wrote:

                         

                        According to this brief interchange http://cubieboard.org/about/, 100 CubieBetaBoards should be available 1 September.  Not clear about whether they're assembled or just PC Boards.  They have an interesting minimalist web site.  I'm looking forward to seeing how this plays out.

                        The cubieboard Web site is getting less minimalist.  Nice photos of beta board are at http://cubieboard.org/2012/09/02/some-pictures-of-cubieboard/.  Note the SATA connector, IR, and discrete 1GB DDR3.

                         

                        Note: I am not affiliated with cubieboard or any other tiny computer's organization.  I figure the more, the merrier, and may the most open design win

                          • Re: Wanted, help finding embedded linux board

                            The cubieboard Web site is getting less minimalist.  Nice photos of beta board are at http://cubieboard.org/2012/09/02/some-pictures-of-cubieboard/.  Note the SATA connector, IR, and discrete 1GB DDR3.

                            That's actually beginning to look rather interesting.  Am I correct in thinking the A10 doesn't have native ethernet ?  If so how are they doing the network port, I don't see a lan9512 on there...

                              • Re: Wanted, help finding embedded linux board
                                John Beetem

                                selsinork wrote:

                                The cubieboard Web site is getting less minimalist.  Nice photos of beta board are at http://cubieboard.org/2012/09/02/some-pictures-of-cubieboard/.  Note the SATA connector, IR, and discrete 1GB DDR3.

                                That's actually beginning to look rather interesting.  Am I correct in thinking the A10 doesn't have native ethernet ?  If so how are they doing the network port, I don't see a lan9512 on there...

                                A10 does have Ethernet MAC.  It's the A13 (for tablets and phones) that doesn't.

                                 

                                For details on A10, including a sparse datasheet, see http://linux-sunxi.org/A10.  By "sparse", I mean that if you hunt carefully you can find a block diagram with "E-Mac" on it and MII signals on pinout, but you can't find a section about Ethernet in the Table of Contents.

                                  • Re: Wanted, help finding embedded linux board

                                    A10 does have Ethernet MAC.  It's the A13 (for tablets and phones) that doesn't.

                                    Ah...  but from the looks of that it doesn't have SATA, so how does the Cubieboard get the sata connection ?

                                     

                                    Maybe it was the OdroidX I was thinking about that had usb-ethernet.  Looked at so many of those block diagrams and they all seem to reveal some interesting/useful function is sat on the end of a usb somewhere that I'm getting mixed up...

                                      • Re: Wanted, help finding embedded linux board
                                        John Beetem

                                        selsinork wrote:

                                         

                                        A10 does have Ethernet MAC.  It's the A13 (for tablets and phones) that doesn't.

                                        Ah...  but from the looks of that it doesn't have SATA, so how does the Cubieboard get the sata connection ?

                                         

                                        Maybe it was the OdroidX I was thinking about that had usb-ethernet.  Looked at so many of those block diagrams and they all seem to reveal some interesting/useful function is sat on the end of a usb somewhere that I'm getting mixed up...

                                        The A10-OLinuXino schematics have SATA hooked up.  I think it's just that the A10 datasheet is very sparse.  Olimex must have a more complete (and more confidential) data sheet.  There's been recent A1X-OLinuXino news: see http://www.element14.com/community/message/59701?tstart=30#59701.

                                         

                                        Yes, I think the ODROID-X has USB-based Ethernet.

                                          • Re: Wanted, help finding embedded linux board

                                            The A10 OlinuXino is actually looking rather interesting, I wasn't all that interested in the A13.  Bit of a shame it's going to end up quite so large though. The Cubieboard will be much easier to integrate into something else as it's 'brains'.

                                             

                                            Interesting to read on the olinuxino github page that they do seem to have some sort of roadmap and future plans. Their Step 4 idea of using a Freescale iMX6 allowing gigabit ethernet, up to 4Gb ram and the option of 1 to 4 cores seems to have a lot of potential

                                              • Re: Wanted, help finding embedded linux board
                                                John Beetem

                                                There's a new posting at Slashdot about Rhombus Tech's A10-based EOMA-68 card: http://hardware.slashdot.org/story/12/09/07/2322207/rhombus-tech-a10-eoma-68-cpu-card-schematics-completed. This is a CPU card using a PCMCIA connector, which IMO is a nice form factor for tablets, but may be too restrictive for your purposes.  No idea when prototypes will be available.

                                                 

                                                I'm still watching for iMX6 SoCs, and especially a QuickStart board.  Freescale tends to have way too many different chips which I think contributes to their legendary inability to release new chips on time.  It's too bad, since Freescale chips tend to have excellent features and very open documentation.  I also prefer the PowerPC architecture to both ARM and x86.

                                                  • Re: Wanted, help finding embedded linux board
                                                    FreescaleTools_and_Software

                                                    Hello

                                                    I agree with John, may be the i.MX6 ARM Cortex-A9 processor family has been announced a little bit to earlier ...

                                                    ... BUT it is official now, i.MX6 Solo, Solo Lite, Duo, Duo Lite and Quad are in production (at least in industrial qualification) since Electronica.

                                                    For proof, you can request samples and download the datasheets on Freescale website HERE

                                                     

                                                    Concerning the board, Element14 is taking pre-order for the i.MX6 Sabre-Lite which is quite powerfull considering its features :

                                                    - i.MX6 in Quad Core version @1GHz each with a video accelerator (encoding/decoding up to Full-HD 1080p), a 2D and a 3D accelerator with a composition Engine from Vivante

                                                    - 1GB of 64-bit wide DDR3 @532MHz

                                                    - 2x SD-Card Slots (SD and µSD)

                                                    - 3x USB ports (2x Host and 1x OTG)

                                                    - 1x 10/100/1Gb IEEE1588 Ethernet port

                                                    - SATA and PCI-Express ports

                                                    - 3x Display outputs (HDMI, LVDS and RGB)

                                                    - Analog (headphone, microphone) and Digital Audio (HDMI)

                                                    - Also include :

                                                         4GB SD-card preloaded with Timesys LinuxLink Embedded Linux Image (Kernel v3.0)
                                                    More information HERE

                                                      • Re: Wanted, help finding embedded linux board

                                                        I'm actually quite tempted to get one of those for a look, however I'd take issue with some of the specs. According to the iMX6 eratta document, there's some internal bandwidth limitation that means you can't get more than ~400Mb/s total throughput on the ethernet, so that's not quite 1G.

                                                        I also saw mention that if you want to use USB then the clock requirement means you can't run at 1Ghz - 994MHz or something.

                                                         

                                                        Ok, so it supposedly has PCIe which might help, and the manual says this is available on P23, but P23 certainly isn't obvious on any of the photos.  I'm interested here as I'd like to find out what awful type of connector it's on, back in the original post I said things with horrible connectors would be unlikely to be considered..

                                                         

                                                        GPIO's, such as they are, seem to be splattered across multiple connectors and mixed in with other features, so potentially unuseable anyway.

                                                         

                                                        Then there's 'Kernel v3.0'. Sorry, that just doesn't cut it. Needs to be up at somthhing like 3.4, there's been way too much churn in the linux arm tree with things like devicetree, pinctrl etc that the 3.0 drivers are going to be much harder to forward port to a useful kernel.

                                                        Also, in this respect, I'd like to see some evidence that there's some effort being made to get all this stuff into the mainstream linux kernel. Being stuck with 3.0 in five years time wouldn't be good - same goes for any other arm board though.

                                                         

                                                        Finally, back in the original post I suggested a budget of $50, this board will run to £153.63, considerably more than $50

                                                         

                                                        I do like the iMX6 and I think it has lots of potential, but something like the Wandboard (wandboard.org) seems to be much more in line with my original question.  Sabre-Lite seems very much aimed at some sort of android tablet

                                                         

                                                        That said, I see there's some in stock and I'm able to actually order a Sabre-Lite today, so maybe I will

                                                          • Re: Wanted, help finding embedded linux board
                                                            John Beetem

                                                            selsinork wrote:

                                                             

                                                            Ok, so it supposedly has PCIe which might help, and the manual says this is available on P23, but P23 certainly isn't obvious on any of the photos.  I'm interested here as I'd like to find out what awful type of connector it's on, back in the original post I said things with horrible connectors would be unlikely to be considered..

                                                            PCIe is the white 7-pin connector near the HDMI jack J4.  It's labeled "PCIe" on the silkscreen, with "J23" in tiny letters near the Micro SDcard jack J20.  You can zoom into the photo on page 6 of the MCIMX6Q-SL user manual.

                                                              • Re: Wanted, help finding embedded linux board

                                                                John, I admire your dedication to hunting down stuff like this. I'd wrongly assumed the photos would be the usual sort that are so low res that there'd be no point trying to zoom in.

                                                                 

                                                                But with that answer, the questions has to be whether element14 will be supplying breakout boards for the Sabre so that we can get useful access to any of the features on horrible connectors.  A quick search suggests there's nothing available currently.

                                                                  • Re: Wanted, help finding embedded linux board
                                                                    John Beetem

                                                                    selsinork wrote:

                                                                     

                                                                    John, I admire your dedication to hunting down stuff like this. I'd wrongly assumed the photos would be the usual sort that are so low res that there'd be no point trying to zoom in.

                                                                     

                                                                    But with that answer, the questions has to be whether element14 will be supplying breakout boards for the Sabre so that we can get useful access to any of the features on horrible connectors.  A quick search suggests there's nothing available currently.

                                                                    Thanks, but I have a personal interest in PCIe so I was curious.  I have an FPGA design for a client that's currently 32-bit PCI but at some point we'll probably have to migrate to PCIe because it's getting harder to find SoCs that have 32-bit PCI.  So I'll need something for prototyping the design.  On the FPGA side, Xilinx Spartan-6 with the "T" option is promising except that the cheapest part (XC6SLX25T) is US$50 and has way more gates than we need.

                                                                     

                                                                    There is a standard for PCIe over a cable, but products are hideously expensive.  I think it's possible to use a SATA cable, which are very cheap.  I would hope Freescale has a high-speed cable in mind for J23.

                                                                      • Re: Wanted, help finding embedded linux board

                                                                        John Beetem wrote:

                                                                        There is a standard for PCIe over a cable, but products are hideously expensive.  I think it's possible to use a SATA cable, which are very cheap.  I would hope Freescale has a high-speed cable in mind for J23.

                                                                        You'd hope so, but from the bom the connector appears to be just a standard board to single wire with a crimp terminal sort of thing. Given the high speeds expected for PCIe I'd imagine you'd need to keep that really short to avoid all sorts of problems. I've posted a question over in the Sabre-lite group to see if they'll be supplying anything. I'd hate to have to make them up by hand.

                                                                         

                                                                        The sata cable is an interesting suggestion, but even that leaves you needing some sort of an adapter from the current connector. Having had the occasion to hack the end off a sata cable and try to solder something else onto it, it's not something I'd recommend if there's any other choice.

                                                                         

                                                                        From what I've seen, the cabled external PCIe stuff is very similar to Infiniband or external SAS although with an incompatible connector to prevent accidental incorrect connections.

                                                                • Re: Wanted, help finding embedded linux board

                                                                  I should also say... Quite disappointing that the element14 link to the Sable-Lite ares shows  discussions - 0 , documents - 0, and there's so obvious link to a downloadable sd-card image or anything.

                                                                   

                                                                  I realise these are still very new, hopefully the group might take off..  I suspect it'll be slow though. 150 quid vs 30 quid raspberry pi is tough competition. Regardless of anything else I do think the RPF made a good choice in sticking to a very low price point. Yes the Sabre-lite is better in so many ways, but also has lots of 'features' nobody will use and 5x the cost is much harder to justify as a throwaway whim.

                                                    • Re: Wanted, help finding embedded linux board
                                                      Drew Fustini

                                                      I recently joined the Cubie board Google Group: https://groups.google.com/forum/#!forum/cubieboard   It seems like a good way to stay up to date with the project.  I've also been on the arm-netbook mailing list too which is informative for these types of boards: http://lists.phcomp.co.uk/pipermail/arm-netbook/  Finally, the wiki that Cubie links to is interesting: http://linux-sunxi.org/Main_Page

                                                • Re: Wanted, help finding embedded linux board

                                                  Some interesting Freescale i.MX boards available from http://bluetechnix.at/rainbow2006/site/i_mx_family/412/i_mx_family.aspx unfortunately they all seem somewhat out of range from a cost perspective.

                                                  • Re: Wanted, help finding embedded linux board

                                                    Just stumbled across DEV KIT,SITARA, AM3359 ARM CORTEX-A8DEV KIT,SITARA, AM3359 ARM CORTEX-A8 which looks surprisingly good with two network ports, decent PMIC etc.. Now the question is why does $99 work out to £100 +VAT ?