Interrupted example for ATtiny85

tinytest.ino

#include <Interrupted.h>

#define LED     0
#define TIMER   1
#define BUTTON  2

Watchdog timer(TIMER, 1);
External button(BUTTON, LOW);
PinChangeGroup portb;
PinChange led(LED, portb); 
Devices devices;

void setup(void)
{
  devices.add(timer);
  devices.add(led);
  devices.add(button);
  devices.begin();

  pinMode(LED, OUTPUT);
  digitalWrite(LED, HIGH);
}

void loop(void)
{
  switch (devices.select()) {
  case BUTTON:
    digitalWrite(LED, HIGH);
    break;
  case TIMER:
    digitalWrite(LED, LOW);
    break;
  case LED:
    timer.enable(led.is_on());
    break;
  }
}