analogRead attaches the pin to ADC channel, which remaps it off the PU circuit. If you set the mode back to INPUT_PULLUP after the read, it should work as expected.


This did the trick! Thanks @Ibernstone! Quick recap and some SEO terms for anyone googling this: if the INPUT_PULLUP or INPUT ...

I will give this a shot now and report back, thanks!

I'm programming a custom ESP32 board using Arduino where GPIO25 and GPIO32 are connected to pogo pins via <10mm traces and to nothing else. The goal is to poll for a short between them as part of an alignment procedure - pretty straightforward.

The issue is, pinMode(X, INPUT_PULLUP) does not ...