General • Re: RP2040 clone pins 26-29 (ADC) not working as GPIO

it's just a different circuit and programming you must be aware of.

That is the crux of my question. If there is something I can do from a programming point of view I would like to know, bearing in mind I am using micropython. The board in question is this:It is a really cheap one from China. I use the term "clone" because the other RP2040 boards I have appear to be a copy of the Waveshare "Tiny". But those "Tiny" ones I have successfully used the GPIOs 26-29 without having to do anything other than specify the pins as input with pull ups. I switched from those to the one in the image because I needed more I.O. thinking all would be well. (Naive I know) So the question remains do I not use the ADC pins for GPIO and re design my PCB (not a great option) or might there be a programming route to try before I bail on my prototype PCBs too?

Someone with a bad board should use a multimeter to do some checks, then hopefully we can get some good data on the problem

Well I have "bad" boards and a multimeter. All I have done so far is measure between pin 29 and gnd, with the board un powered and the multimeter claims 630M Ohm, 21k with it connected via USB. Without more guidance I can't be much more help but I would like to try anything before I have to give up on these, I bought ten of them!

Statistics: Posted by jimseng — Fri Aug 15, 2025 3:24 pm

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