hi,
I'm trying to learn the Interrupt.
I've almost rewritten Arduino Playground - PcInt without using pins_arduino.h libraries, just Regiter manipulation and ISR() routine.
But one function seems hard to replace: curr = *portInputRegister(port+2);
Seems what this function return the pins that has changed. I can simulate its work simply looking at PORTD ecc and saving the old state... but PORTX or PINX is always 0...
who can help me?