#include "avr/io.h"
#include "avr/interrupt.h"

int main ()
{
	DDRC = 1<<3;	
	PORTD = 1<<2;		
	GICR = (1<<INT0);	
	sei ();			

	while (1);			
}

ISR (INT0_vect)			
{
	PORTC ^= (1<<3);		
}