#include "avr/io.h"
  int main ( )
  {
    unsigned char t1;
    ddrb = 0xff;    
    portd = 0xff;  
    tccr1a = 0;    
    tccr1b = 0x45;
    while ((tifr&(1<<icf1)) == 0);
    t1 = icr1l;  
    tifr = (1<<icf1);  
    tccr1b = 0x05;  
    while ((tifr&(1<<icf1)) == 0);
    portb = icr1l - t1;  
    tifr = (1<<icf1);  
    while (1);    
    return 0;
  }