#include "at90s8515.h"

int count; // Timer/Counter0 Overflow counter

int main (void) {
  DDRB = 0xff; // configure as output
  PORTB = 0xff; // turn all leds off
  DDRD = 0x0; // configure as input

  SREG |= 1<<7; // Global Interrupt enable
  GIMSK |= 1<<6; // External Interrupt Request 0 enable
  TIMSK |= 1<<1; // Timer/Counter0 Overflow Interrupt enable
  MCUCR |= 0xfe; // the falling edge of INT0 generates an interrupt request

  while (1) {}
  return 0;
}

void EXT_INT0 (void) SIGNAL;

void TIM0_OVF (void) SIGNAL;

void EXT_INT0 (void) {
  count = 0;
  if (MCUCR == 0xfe) {
    TCCR0 = 0x05; // start Timer/Counter0 with prescale CK/1024
    MCUCR |= 0xff; // the rising edge of INT0 generates an interrupt request
  } else {
    MCUCR |= 0xfe; // the falling edge of INT0 generates an interrupt request
    TCCR0 = 0x0; // stop Timer/Counter0
    PORTB |= 1<<2; // turn off led 2
  }
}

void TIM0_OVF (void) {
  count++;
  if (count == 35) {
    PORTB &= ~(1<<2); // turn on led 2
    TCCR0 = 0x0; // stop Timer/Counter0
  }
}