void setup() {
  volatile char* portf_dir = 0x30;
  volatile char* portk_dir = 0x107;
  *portf_dir = 0xff;
  *portk_dir = 0xff;
}

void loop() {
  volatile char* portf_data = 0x31;
  volatile char* portk_data = 0x108;
  *portf_data = 0x5b;
  *portk_data = 0x07;
}