Port, board and/or hardware

rp2 / rp2350A / Waveshare RP2350 1.28 in Round LCD

MicroPython version

This works:

b9f6698d3 - (HEAD -> rp2-add-2350) tools/ci.sh: Add RPI_PICO2 to CI. (4 months ago) <Damien George>
That is the branch of PR #15619, back 4 months ago.

Merged versions like 1.24.0, 1.24.1, etc., do not work.

Reproduction

Build firmware image the usual way, program the chip by copying to the USB drive of the device.

Expected behaviour

Expected the device to enumerate on the USB port and be able to start talking over REPL or other means.

Observed behaviour

Nothing happens. Device is flashed with some code, because I can perform a picotool info on a "dead" board and get data back.

Additional Information

I've been struggling with this for a couple of days now. I have the Waveshare board which runs just fine with a UF2 provided by Waveshare. But I could not get it to run using MicroPython which I built locally. As a sanity check, I successfully built and ran MicroPython on an RP2040 Pico 1 and an Pimoroni Pico Plus 2. Interestingly I could run the Waveshare UF2 on the Pimoroni board no problem. I tried version 1.24.1 and also 1.24.0 (the version which Waveshare was using). A request to Waveshare to get a copy of their board configuration files has been unanswered for several days now.

Finally at the suggestion of @mattytrentini, I rolled back to the PR version from like 4 months ago (see above). Bingo! Everything suddenly works now. So something happened between the PR and the final merge that caused this particular board to "break". I have gone over the schematics several times, and can't find any reason to explain the failure.

Just tonight, a few hours before solving the problem, I realized that the Waveshare board uses the RP2350A chip, but the Pimoroni board uses the RP2350B chip. Then I found issue #16391, which I noticed also uses the A chip (but so does the Raspberry Pi Pico 2 module, so that seems like a dead end).

If additional dumps will be helpful, I can provide OTP data, pico tool info text, version numbers, etc.

Code of Conduct

Yes, I agree