Is it possible for a pin of a microcontroller to be damaged in such a way that it can still function as a digital output pin but no longer as an analog input pin?
I find it odd, but it seems to have happened to one of my ATtiny85s.
My prototyping board with wires all over the place accidentally fell off my desk. Thereafter one of the pins (chip pin 2) that I had been using as an analog input pin no longer seemed to be working. With the chip removed from the circuit the pin in question measures a relatively low resistance to ground (about 250?) whereas in a new chip the resistance value is very high. On the other hand, as an experiment, I uploaded the “blink” program to the chip, and found that each of the chip pins 2, 3, 4, 5, and 6 are still working perfectly as digital output pins.