I'm a little bit late to the party here. The rp2040 is a great chip at a decent price point. However the internal ADC is quite bad for wide range readings. Th

I'm a little bit late to the party here. The rp2040 is a great chip at a decent price point. However the internal ADC is quite bad for wide range readings. There's a few points around 512 / 1536 etc where it gets a "personality" in the readings. AVR seems to have this down much better along with internal references for even more accuracy.