1 5 6 7 8 9 10 Previous Next 143 Replies Latest reply: Dec 15, 2013 6:03 PM by John Beetem Go to original post Branched from an earlier discussion. RSS
  • 90. Re: Role for FPGA or CPLD with Raspberry Pi
    John Beetem

    John Beetem wrote:

     

    Alex Eames posted a nice review of the Guzunty Pi at: http://raspi.tv/2013/guzunty-pi-open-source-cpld-board-for-the-raspberry-pi

     

    As I've said upstream, the XC 9572 XL is a terrific CPLD which I've used in a lot of work projects.  Very nice balance of resources.

     

    Due to a high level of interest, Derek has now made Guzunty Pi boards and kits available world wide: https://github.com/Guzunty/Pi/wiki/Buy-a-Guzunty.  First programmable logic board I've seen that costs less than a RasPi

     

    IMO Guzunty Pi would be a nice addition to element14's RasPi accessory assortment.

  • 91. Re: Role for FPGA or CPLD with Raspberry Pi
    guzunty

    Hi John,

     

    Thank you very much for the words of encouragement.

     

    Yes, there were a number of design goals I set myself:

     

    - Low cost.

      There seemed to me no point in doubling the cost of a Rasperry Pi with expensive add-ons. I wanted to create a 'Pocket money

      peripheral'. CPLDs are so much cheaper than FPGAs, it's a great way to dip your toe in the water before thinking about trading up

       to FPGA.

    - Easy to build.

      There's no better way to keep the cost down than to make it yourself. And the satisfaction of seeing your creation working comes

      absolutely free! I therefore wanted the board to be very easy to build. It is through hole soldering only, and the solder mask on the

      PCB makes it easier than building on stripboard. If you follow the instructions on GitHub carefully, you can build one of these for

      sure. At this time, I have no reports of any failed builds out in the field.

    - Downloadable cores.

      I think everyone will agree that learning to design your own core does require some investment of time. By offering ready made

      cores, you can start right away, knowing that there is more you can do with it later.

    - Educational.

      Aligns with the Raspberry Pi philosophy.  I think the Pi revolution is about more than learning to program software. Once you have

      a Guzunty running on your RPi, who could resist the temptation to learn HDL and begin to design cores yourself? Certainly not

      me :-)

     

    I must have done something right, because interest in the Guzunty CPLD add on for the RPi has been fantastic. I'm now able to

    offer a kit of parts anywhere in the world. See https://github.com/Guzunty/Pi/wiki. Just click on Pages > Buy a Guzunty

     

    best regards and thanks to everyone for the support,

     

    Derek

  • 92. Re: Role for FPGA or CPLD with Raspberry Pi
    morgaine

    More information from Derek about his super little Guzunty CPLD board over in  this other thread.

  • 93. Re: Role for FPGA or CPLD with Raspberry Pi
    John Beetem

    There's a nice new write-up of Valent F(X) FPGA boards for RasPi and BeagleBone at Linux Gizmos: BeagleBone and Raspberry Pi gain FPGA add-ons.  Boards not yet available commercially, but they're considering a Kickstarter.

  • 94. Re: Role for FPGA or CPLD with Raspberry Pi
    morgaine

    Very interesting.  I had a good chuckle at "LOGI-BONE SLIM" and "LOGI-BONE PHAT". :-)

     

    Care to hazard a guess at pricing?

  • 95. Re: Role for FPGA or CPLD with Raspberry Pi
    guzunty

    I heard "$99 or less" on the grapevine.

     

    A very good price for a FPGA of this capacity, but it is quite a lot for an add-on for a $25 host, IMHO. I considered creating a Guzunty FPGA board, but decided against it for this reason. The current Guzunty is only $25 for the kit or even less if you source your own parts and build one from a bare PCB.

     

    Of course, there is no comparison from a capacity perspective. A Spartan and an XC9572XL are chalk and cheese. But for those who just want an introduction to programmable logic, I think it is going to be too big an investment for many.

     

    I'll be very interested to see how it goes, though. I wish them luck.

  • 96. Re: Role for FPGA or CPLD with Raspberry Pi
    morgaine

    I think you're right about the questionable appropriateness of a $99 add-on board for the $35 niche, Derek.  If finances stretch that far then it doesn't really make a lot of sense to couple it with a very low-end CPU board that introduces unnecessary problems and limitations.  Sensibly, one would choose a more capable processor platform.

     

    In contrast, Guzunty Pi is an excellent match of processor and programmable logic in both capability and pricing.

  • 97. Re: Role for FPGA or CPLD with Raspberry Pi
    guzunty

    We also considered a CPLD add on for the BBB when it was first announced.

     

    However, there we came to the conclusion that the dedicated IO processors in that product provide enough real time heavy lifting that a CPLD probably wouldn't add very much. What do you think?

     

    The much greater resources in a Spartan make it a different equation, though. I think Logi-bone may end up being a better match for the BBB.

  • 98. Re: Role for FPGA or CPLD with Raspberry Pi
    John Beetem

    Morgaine Dinova wrote:

     

    Very interesting.  I had a good chuckle at "LOGI-BONE SLIM" and "LOGI-BONE PHAT". :-)

     

    Care to hazard a guess at pricing?

    I asked about Mark-1 pricing last year in this RasPi Forum thread.  Michael Jones said they were "shooting for under 100".  He didn't say whether this was GBP, USD, or Euros.

     

    Edit: For comparison, you can get a Papillio Pro with Spartan 6 LX9 for US$85 or Papillio One with Spartan 3 250E for US$38 -- very attractive.

  • 99. Re: Role for FPGA or CPLD with Raspberry Pi
    morgaine

    Derek Campbell wrote:

     

    We also considered a CPLD add on for the BBB when it was first announced.

     

    However, there we came to the conclusion that the dedicated IO processors in that product provide enough real time heavy lifting that a CPLD probably wouldn't add very much. What do you think?

     

    Although that's true, programmable logic and realtime software/microcontrollers are two different things. If the goal is education or promoting the use of programmable logic among enthusiasts then there is ample room for CPLDs as BBB add-ons at Guzunty Pi prices or thereabouts (a full cape would necessarily cost a bit more).

     

    If the goal is simply to meet a realtime requirement then I'd agree, BBB already has a lot of capability in that regard just on its own.

     

    The much greater resources in a Spartan make it a different equation, though. I think Logi-bone may end up being a better match for the BBB.

     

    Oh, I'm even-handed in that respect --- a $99 FPGA board doesn't make much sense on a BBB either!  Although the BBB has more capability than the Pi, it's in the same price niche, so it wouldn't really be a price-balanced pairing.

     

    Perhaps something like the dual-core A20-OLinuXino-MICRO-4GB would provide a better-matched CPU foundation for a $99 FPGA board?

  • 100. Re: Role for FPGA or CPLD with Raspberry Pi
    John Beetem

    Morgaine Dinova wrote:

     

    Perhaps something like the dual-core A20-OLinuXino-MICRO-4GB would provide a better-matched CPU foundation for a $99 FPGA board?

    Or, for that same US$99 you'll soon be able to get a Zynq 7010 board with dual-core Cortex-A9 and 1GB DDR3.  It also happens to have a 16-core parallel processor

     

    [Yes, I know you already know about that board -- I'm just having fun and reminding the community of the possibilities.]

  • 101. Re: Role for FPGA or CPLD with Raspberry Pi
    morgaine

    It's worth pointing out that an FPGA add-on board doesn't have to cost $99.  Lattice, Altera and Xilinx all have FPGA devices listed for less than £10 single unit pricing at Farnell UK, and even a bottom-end Spartan-6 device costs only £13.45.

  • 102. Re: Role for FPGA or CPLD with Raspberry Pi
    morgaine

    Indeed, we'll all be playing with Parallella in November or not long thereafter.

  • 103. Re: Role for FPGA or CPLD with Raspberry Pi
    guzunty

    The Spartan-6 price is indeed very attractive, and believe me, it was a very tempting idea. However, as I know you know, the cost of the bare component is not the end of the story.

     

    The Spartan-6 comes in (IIRC) a QFP-144 package which precludes home assembly for most people likely to be interested (I know it wouldn't put _you_ off! :-) ).

     

    Of course, there is the Papilio Pro at $85, but I think a bare bones FPGA add on could definitely be made for even less than that. Guzunty proves that the host board can take care of the programming directly, so a lot of peripheral hardware needed on a standalone board can be eliminated.

     

    Even paring the support hardware back, you're still left with the problem of buildability. Ease of assembly is one reason we designed the Guzunty Pi to use a device that can use a through hole PLCC socket. Pre-assembled as opposed to self assembled adds quite a bit to the bottom line.

  • 104. Re: Role for FPGA or CPLD with Raspberry Pi
    morgaine

    Derek Campbell wrote:

     

    Even paring the support hardware back, you're still left with the problem of buildability. Ease of assembly is one reason we designed the Guzunty Pi to use a device that can use a through hole PLCC socket.

     

    That design choice was probably a very good one in that it made assembly easy for newcomers to open hardware.

     

    John has mentioned on many occasions his long-term project for a fully open source toolpath for programmable logic.  I wonder if a simple board like yours (reworked to be less specific to Pi) wouldn't provide a suitable first target on which to collaborate?

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