#define TODAS_VEZES digitalRead(LED_BUILTIN)
const int UMA_VEZ = digitalRead(LED_BUILTIN);
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  Serial.print("Sempre: ");Serial.println(TODAS_VEZES);
  Serial.print("1ª vez: ");Serial.println(UMA_VEZ);
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
  delay(1000);
}