Ah, my bad. The issue in #9 was the infinite output that was shown in the first print screen.
However, I can confirm that the issue has been fixed by using the setup() you provided. Here is the full initial sketch, updated:
void setup() {
Serial.begin(9600);
while (!Serial) {
;
}
Serial.println("starting");
pinMode(LED_BUILTIN, OUTPUT);
}
void loop() {
digitalWrite(LED_BUILTIN, HIGH);
delay(1000);
digitalWrite(LED_BUILTIN, LOW);
delay(1000);
}
Printing something in the setup seems to be resetting the serial monitor enough for it to stop outputting endlessly. Everything is now working perfectly.
Thank you so much for your help Aarg, I hope you have a fantastic day ![]()