// https://docs.arduino.cc/built-in-examples/basics/Blink


void setup() {
    pinMode(LED_BUILTIN, OUTPUT);
}

void internLedSet(int state) {
    if ( state == 1 ) {
        digitalWrite(LED_BUILTIN, HIGH);
    } else if ( state == 0 ) {
        digitalWrite(LED_BUILTIN, LOW);
    }
}

void loop() {
    internLedSet(1);
    delay(1000);
    internLedSet(0);
    delay(1000);
}