AVR Studio 4 Simulation

#include <avr/io.h>

#include <compat/deprecated.h> 

#include <inttypes.h>

#include <avr/interrupt.h>

#define TRUE 1

#define FALSE 0

//toggle bit Key1

  uint8_t key2Toggle = FALSE;

SIGNAL(SIG_INTERRUPT0) {

  key2Toggle = key2Toggle ^ TRUE;

}

int main(void) {

  // Port Output enable

  sbi(DDRB, PB4);

  //sbi(PORTB, PB4);

  // Port D PD2 Input enable

  cbi(DDRD, PD2);

  //activate Pull up Resistor

  sbi(PORTD, PD2);

  //Rising edge for INT0

  MCUCR |= (1<<ISC01) | (1<<ISC00);

  //Allow INT0

  GICR |= (1<<INT0);

  //Allow global interrupt

  sei();

  // main program 

  while(TRUE)

  {

  if(key2Toggle == TRUE) {

    // Port enable

    sbi(PORTB, PB4);      

    }

  if(key2Toggle == FALSE) {

    // Port disable

    cbi(PORTB, PB4);    

  }    

  }

}