void setup() {
  // put your setup code here, to run once:
  volatile int i, j;
  volatile char *dirk, *dirf, *dira, *dirc;
  volatile char *ink, *outf, *outa, *outc;
  dirk = 0x107; dirf = 0x30; dira = 0x21, dirc = 0x27;
  ink = 0x106; outf = 0x31; outa = 0x22, outc = 0x28;
  *dirk = 0x00; *dirf = 0x0F; *dira = 0x0F, *dirc = 0x0F;
  //*outa = 0x05;
  while(1)
  {
    for(i=0; i<4; i++)
    {
      *outf = 1<<i;
      *outa = *ink;
      if(*ink != 0)
      {
        *outc = 1<<i;
        for(j=0; j<10000; j++);
        *outc = 0x00;
      }
    }
  }

}

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

}