test ESP32 Feather Arduino IDE C code

sketch_jan25a.c

void setup() {
  // init built-in LED pin as output
  pinMode(LED_BUILTIN, OUTPUT);
  // init USB serial converter so we have a port created
  Serial.begin(115200);

  // optional but IMPORTANT
  // wait for the serial port to be ready (good for debugging)
  while(!Serial) {;   /* wait for serial connection */ }

  Serial.println("setup has completed.");
}

void loop() {
  Serial.println("LED on");
  digitalWrite(LED_BUILTIN, HIGH);    // tun LED on (HIGH is voltage)
  delay(1000);
  Serial.println("LED off");
  digitalWrite(LED_BUILTIN, LOW);     // turn the LED off
  delay(3000);
}