void setup() {
  // put your setup code here, to run once:
    volatile char *dr1,*dr2;
    dr1=0x30;
    dr2=0x107;
    *dr1=0xff;
    *dr2=0xff;

}

void loop() {
  // put your main code here, to run repeatedly:
  volatile char *in,*control;
  volatile long i;

  in=0x31;
  control=0x108;
  *in=0x01;
  
  *control=0x02;
  for(i=0;i<100000;i++);
  *control=0x01; 
    for(i=0;i<100000;i++);
}