#define ledPin 4

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(ledPin, OUTPUT);  //輸出LED
}

void loop() {
  analogWrite(ledPin, 0);
  delay(500);
  analogWrite(ledPin, 1);
  delay(500);
  analogWrite(ledPin, 20);
  delay(500);
  analogWrite(ledPin, 100);
  delay(500);
  analogWrite(ledPin, 255); // 100% duty cycle
  delay(500);
}