void setup() {
  // put your setup code here, to run once:
  volatile char *DDR_F, *DDR_K;
  DDR_F = 0x30;  DDR_K = 0x107;
  *DDR_F = 0xFF; *DDR_K = 0x00;

  volatile  char *out_F, *in_K;
  out_F = 0x31; in_K = 0x106;
  volatile long i;
  while(1){
    *out_F = *in_K;
    for(i=0;i<10000;i++);
    *out_F = 0x00;
  }
}
void loop() {

}