So, I'm using the Arduino Nano to develop a board. On this board I have a relay who it's switched by the Nano.
But during the execution of the code, I need to know the state of the output to make something. The usual fuction just to read the output last state would be the digitalRead(). But if I read the digital pin D9 (who it's connected to the relay driver) the fuction allways return 0 (false, off). If I read another digital pin, that fuction work normaly.
To get around the problem, I'm reading directly the PORT register. That isn't a problem, but I just whould like to know if someone has found this problem too.