void init_tmr();

void setup() {
  // put your setup code here, to run once:
init_tmr();
 volatile char *ddr =(char*)0x30;
*ddr = 0x01;

}

void init_tmr(){
volatile  char *controlReg=0x80;
volatile  char *pre= 0x81;
volatile  short *tmr= 0x84;
volatile  short *cmp= 0x88;
volatile  char *msk=0x6f;


*controlReg=0;
*pre=0x0c;
*cmp=62500;
*tmr=0;
*msk=0x02;
}

ISR(TIMER1_COMPA_vect){
volatile char *op=(volatile char*)0x31;

(*op)^=(0x01);
}

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


}