void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  ledcAttachPin(13,0);  // attach PWM channel 0 to GPIO pin 34
  ledcSetup(0,1000,8);  // setup PWM 0 to 1kHz, with 8bits resolution (0-256)
}

void loop() {
  // put your main code here, to run repeatedly:
  for(int i=0; i<256; i++){
    ledcWrite(0,i);
    Serial.println(i);
    delay(10); // this speeds up the simulation
  }
  for(int i=256; i>0; i--){
    ledcWrite(0,i);
    Serial.println(i);
    delay(10); // this speeds up the simulation
  }
}