/*
  Blink LED with UART
  Turns an LED on for one second, then off for one second, repeatedly.
*/
#define YELLOW_LED 12
int incomingByte;

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);

  // https://docs.wokwi.com/guides/serial-monitor
  Serial1.begin(115200);

  delay(100);

  Serial1.println("Press ENTER to start!\n");

  while(!Serial1.available() > 0);
  incomingByte = Serial1.read();

  if(incomingByte == '\n')
    Serial1.println("Blink onboard LED every second!");
}

// the loop function runs over and over again forever
void loop() {

  digitalWrite(LED_BUILTIN, HIGH);  // turn the LED on (HIGH is the voltage level)
  digitalWrite(3, HIGH);  // turn the LED on (HIGH is the voltage level)
  digitalWrite(YELLOW_LED, HIGH);  // turn the LED on (HIGH is the voltage level)

  Serial1.print("Onboard LED is ON!\n");

  delay(1000);                      // wait for a second

  digitalWrite(LED_BUILTIN, LOW);   // turn the LED off by making the voltage LOW
  digitalWrite(3, LOW);  // turn the LED on (HIGH is the voltage level)
  digitalWrite(YELLOW_LED, LOW);  // turn the LED on (HIGH is the voltage level)

  Serial1.print("Onboard LED is OFF!\n");

  delay(1000);                      // wait for a second
}