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P2 PCB flash not working. — Parallax Forums

P2 PCB flash not working.

For the past previous few months, I have been working almost every day on P2 trying to learn it better. Recently, I thought of making a custom PCB using. The PCB is ready and working normally when uploaded to RAM using Prop Plug. But I am facing a problem with uploading the code to Flash. It doesn't respond and neither the Propeller Tool shows any error. The flash used here is S25FL.

The schematic is as following:

Any suggested solutions would be highly appreciated.


  • The 100nF cap on the RESN signal could prevent the prog plug from pulling it low with a short pulse. 4.7nF or smaller should be better. Of what brand is the flash IC? This thread might be helpful:

  • RaymanRayman Posts: 12,099

    Right... @ManAtWork tested a bunch and some don't work.
    I'd replace that chip with one that is known to work...

  • Cluso99Cluso99 Posts: 17,837

    I use the S25FL256 on my RetroBlade2. This brand doesn’t require IO2 and IO3.

    There are however slight differences when erasing the flash and I’m unsure about the flash programming code in PropTool, so cannot say for sure this will work with the Spansion flash.

    Are you using a real prop plug? There is a 100nF between the DTR and Reset pin on P2 required and this is effectively in the transistor reset functionality in the prop plug but it’s not in the cheapie USB to serial dongles.

  • TubularTubular Posts: 4,378

    I'm pretty sure we've loaded Retroblade2 flash chips successfully, but probably using the silabs 2102 rather than prop plug. However ozprop was using his own loader for most of that

    Like others I'm suspicious of C38 and would just remove it to see if things come right
    Failing that, pulling P58 low has helped some flash chips

  • RaymanRayman Posts: 12,099

    I see what you mean about c38. That does look like it could be a problem as it will mess with the timings.

    But, isn’t some C nice to have there to prevent noise from triggering a reset. Maybe 10nf would be ok ?

  • RaymanRayman Posts: 12,099
    edited 2021-07-15 11:52

    I just put a 100 nF cap between RESn and GND on a P2 Eval board and flash still works with Prop Tool.

    3024 x 4032 - 3M
  • I had been out of station for a while. I could check your responses only now. I will try to implement your suggestions and see how it comes up. Thank you very much for your valuable suggestions. o:)o:)

  • I just replaced the existing flash in the PCB with Winbond W25Q80DV and it works completely fine.
    Thanks a lot!!!

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