Arduino code:

  * pinMode(GPIO, OUTPUT);\\
  * digitalWrite(GPIO, STATE);\\

  * pinMode(GPIO, INPUT);\\
  * digitalRead(GPIO);\\


The following modes are supported for the basic input and output:\\

  * INPUT sets the GPIO as input without pullup or pulldown (high impedance).
  * OUTPUT sets the GPIO as output/read mode.
  * INPUT_PULLDOWN sets the GPIO as input with the internal pulldown.
  * INPUT_PULLUP sets the GPIO as input with the internal pullup.