#include 
 
#include 
 
// Alphanumeric LCD functions
#include 
#include 
#include 
#include 
// Declare your global variables here
 char   apply_rising=1;  
 unsigned long int t0_ovf=0; 
 unsigned long int high_time=0;
 unsigned long int low_time=0;              
 unsigned  char freq[30];
// External Interrupt 1 service routine
interrupt [EXT_INT0] void ext_int0_isr(void)
{
// Place your code here
TCCR0=0;
if(apply_rising==1)
{
  low_time=t0_ovf*256+TCNT0;
  // INT1 Mode: Falling Edge 
  MCUCR=(0<