int brightness = 0;
int amount = 1;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  ledcSetup(0, 4000, 8);
  ledcAttachPin(15, 0);
}

void loop() {
  delay(10);
  Serial.println(brightness);
  brightness += amount;
  ledcWrite(0, brightness);
  if (brightness == 255 || brightness == 0) {
      amount *= -1;
  }
}