void setup() {
  // put your setup code here, to run once:
  pinMode(12, OUTPUT);
  __asm__("LDI r16,0x10\n\t"); // set data to send to port B B00010000 = 16 = Ox10
  __asm__("LDI r17,0x0\n\t"); // set data to send port B = 0
}

void loop() {
  __asm__   ("startLoop:");
  __asm__
  (
    "  out 0x05,r16\n"
    "  nop\n"
    "  out 0x05,r17\n"
    "  nop\n"
  );

  digitalWrite(12, HIGH);
  __asm__
  (
    "  out 0x05,r17\n"
    "  nop\n"
    "  out 0x05,r16\n"
    "  nop\n"
  );
  digitalWrite(12, LOW);

  __asm__
  (
    "  out 0x05,r16\n"
    "  nop\n"
    "  out 0x05,r17\n"
    "  nop\n"
  );
  __asm__   ("  rjmp startLoop\n");
}