/*
pcint test using attiny84 sitting in a attino x45 programmer

Thanks to The Wandering Engineer for this one;
http://thewanderingengineer.com/2014/08/11/pin-change-interrupts-on-attiny85/

*/

#include "avr/interrupt.h"
 
volatile int val=LOW;
 
void setup()
{
  pinMode(7,INPUT);  //this is the PCINT3 pin @ portA/PCINT0, see http://42bots.com/tutorials/programming-attiny84-attiny44-with-arduino-uno/
                     // and https://c2.staticflickr.com/8/7054/6897568559_599ecce4d4.jpg  
  digitalWrite(7,HIGH);
  pinMode(10,OUTPUT);
  
    GIMSK = 0b00010000;    // turns on pin change interrupts on PCMSK0
    PCMSK0 = 0b00001000;    // turn on interrupts on pins PCINT7:0 ->> PA3 -> pin 10
    sei();                 // enables interrupts
}
 
void loop()
{
  //dummy
}
 
ISR(PCINT0_vect)
{
    val = digitalRead(10);  // read input value
  if (val == HIGH) {         // check if the input is HIGH (button released)
    digitalWrite(10, LOW);  // turn LED OFF
  } else {
    digitalWrite(10, HIGH);  // turn LED ON
  }
}