//USE TIMER1 AND BLINK RED LED EVERY 1 SECOND

    volatile char *outf;
void setup() {
  // put your setup code here, to run once:
  volatile char *dirf;
  dirf=0x30;*dirf=0xff;
  outf=0x31;*outf=0x01;
  TCCR1A=0x00;
  TCCR1B=0x0d;
  OCR1A=15624;
}

void loop() {
  // put your main code here, to run repeatedly:

while((TIFR1&0x02)==0){
//waiting for 1 second
}
*outf=*outf^0x01;//xor operation 
TIFR1=0x02;
}