#define togPin 4 //pin 26 of digital board
void T3delay();
void setup()
{
  DDRA |= (1<<togPin);
}
void loop()
{
  T3delay();
  PORTA= PORTA^0x10; //toggling PA.4
}
void T3delay()
{
  TCNT3H= 0xC2;
  TCNT3L= 0xF7;
  TCCR3A= 0x00;
  TCCR3B= 0x05;
  while(TIFR3 & (1<<TOV3)==0);
  TCCR3B=0;
  TIFR3= 1<<TOV3;
}