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P2D2 - An open hardware reference design for the P2 CPU - Page 38 — Parallax Forums

P2D2 - An open hardware reference design for the P2 CPU

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Comments

  • jlsiliconjlsilicon Posts: 92
    edited 2023-11-17 01:00

    The board has a 2x4 Hdr for Serial on the side - why worry about USB ?

    • Or, atleast just plug USB Plug into SideBus
  • ErNaErNa Posts: 1,742

    Were did you order the boards?

  • RaymanRayman Posts: 13,849

    Just read this thread…. Seems early version topped out at 340 MHz.
    Later some talk of using cooling at 325 MHz. Then, at least one of the later boards could hit 375 MHz.

  • jlsiliconjlsilicon Posts: 92
    edited 2023-11-17 14:31

    I am using the PCB from p26.
    https://forums.parallax.com/discussion/168645/p2d2-an-open-hardware-reference-design-for-the-p2-cpu/p26
    CAM_P2D2R5.zip

    Any other suggested better version ?

    The only other stable version is on p27 that is missing Drill files.
    P2D2-H from p5-p10 has the Serial Hdr - but no Gerbers are provided, and it does not have the later patches anyway.

  • Anybody know of a good GERBER Editor on the net for free ?

    • I dont have any around anymore
      • that can modify / add /remove the Traces & Pads from the Gerber files.
        (I have a few PCB Designers - but nothing that can start from working Gerbers files - besides simple Viewers)
  • jmgjmg Posts: 15,144
    edited 2023-11-17 21:10

    @VonSzarvas said:
    Some gremlins that might need answering or checking along the way... (just thinking aloud- no idea if these are already answered in this thread)

    1. Relatively old design, so it might be that some components are longer be available. (ie. check BOM, replace as required, update layout as required).
    2. USB Serial monitor (USB interface IC) had custom firmware - not sure if that was shared/released to public domain ( @jmg might know about that)
    3. There might have been manufacturing difficulties with the design, which could have been why (or partially why) it never materialised. Something to verify and understand in-case layout tweaks required.
    4. Are the latest BOM, Layout and schematic files available?

    Overall it was a neat compact design, with very many hours of careful thought. Just needs a careful approach (I suspect) to bring it to life, and be prepared to tweak some things.

    Good summary, and good guesses :)

    Sadly, SiLabs have since pulled the EFM8UB3 MCU (that was used to make a better serial path, as an upgrade to the CP2102N, with reset and init smarts too).
    SiLabs also divested the Si5351 product line to Skyworks, and they became very hard to get during the shortage.

    Since that design started, alternative parts have been released :

    An alternate part MS5351M (MSOP10) now exists for Si5351, reports are it is same/better, and the existence of that part keeps prices a lot better at lcsc :)
    Both now well stocked at lcsc
    ​SI5351A-B-GTR SILICON LABS 100+ US$0.6635
    ​MS5351M Hangzhou Ruimeng Tech 100+ US$0.4105 - and they mention an eMSOP10 and a MS1152D in DFN8 2x3mm, Less clear on OTP options ?

    The default Si5351 powers up with no clocks out, but you can buy variants with some initial clock. IIRC Peter chose a ~24?MHz part code.

    WCH now have CH343 / CH9102 parts, and even a CH347, that gives HS-USB link in TSSOP20,they spec 9MBd top (HS-USB needs a crystal)
    https://www.wch-ic.com/products/categories/46.html?pid=1

    Thermally, the P2D2 was not great, being such a small board, and the power path via USB, was matched to modest usages.

  • @jlsilicon said:
    Anybody know of a good GERBER Editor on the net for free ?

    • I dont have any around anymore
      • that can modify / add /remove the Traces & Pads from the Gerber files.
        (I have a few PCB Designers - but nothing that can start from working Gerbers files - besides simple Viewers)

    Diptrace is useful in this regard - there's a board we've been making for decades that the local pcb house lost bromides when moving factories, then they 'scanned it' back to gerbers, complete with minor mechanical offsets.

    Using diptrace I was able to correct mounting hole alignment, modify pads, version text etc

  • Thread split with new effort around this board here: https://forums.parallax.com/discussion/175599/p2-minima-first-pass-design

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