void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(115200);
  // initialize the measurement
  long start = micros();
  digitalWrite(LED_BUILTIN, HIGH);
  // take the measurement
  long duration = micros() - start;
  // print the result
  Serial.print(duration);
}


void loop() {
  // delay(1000);
  //digitalWrite(LED_BUILTIN, LOW);
  //delay(1000);
}