void setup() {

  Serial.begin(9600);

  pinMode(LED_BUILTIN, OUTPUT);

  attachInterrupt(digitalPinToInterrupt(3), print_millis, CHANGE);
  attachInterrupt(digitalPinToInterrupt(2), print_micros, CHANGE);

}

void print_millis() {
  Serial.print("millis: ");
  Serial.println(millis());
}

void print_micros() {
  Serial.print("micros: ");
  Serial.println(micros());
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(500);
  digitalWrite(LED_BUILTIN, LOW);
  delay(500);

}