I'm testing a chip that our lab built, and I need to drive a lot of IO pins (I think I need at least 55 pins).
I wanted to use an Arduino Due to drive these IO pins, but I'm not sure which pins I can actually use as digital IO pins. So I'm looking at the sweet pin diagram that shows all of the many names for every pin on the Arduino due. If I count the number of pins that have a digital pin number in grey next to them, I get 72 potential pins.
There are a few pins that appear to be marked as "unsupported" like RXD2 and TXD2, but I'm guessing that just means the arduino libraries don't support using them as a serial port yet (but I can still use them as a digital IO). Is that correct?
I would like to avoid using pins that are also used for other stuff, particularly the tx and rx pins that are used for programming the board, because I don't want those signals propagating to the chip I'm testing. Are there other pins like that which I should avoid?
Do any of the other pins need to be handle specially in order to be used as a plain old digital IO pin?