ESP32 using Arduino: Internal Pull-ups don't work on GPIO25 or GPIO32

Question

I'm programming a custom ESP32 board using Arduino where GPIO25 and GPIO32 are connected to pogo pins via short 5mm 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 actaully turn on the pullup for either pin; the ADC readings are always floating. Whichever pin I'm using still successfully detects a short when intended, but because It is floating and never pulled high, it causes a lot of false flags. Code below:

    int foo=9999;
    pinMode(25, OUTPUT);
    pinMode(32,INPUT_PULLUP);
    while(foo>0){
        foo=analogRead(32);
        Serial.println(foo);
        //do other stuff
    }

Answer 1

Hi all I got to the bottom of this for anyone googling:

Using analogRead attaches the GPIO pin you're using to the ADC channel and disconnects it from the pull-up. Calling pinMode(X, INPUT_PULLUP) after every analogRead will reinstate the bias.