const int LED_PIN = 2;

int brightness = 0;
int fadeDirection = 1;

void setup() {
  pinMode(LED_PIN, OUTPUT);

  // Set up PWM on LED pin
  ledcAttachPin(LED_PIN, 0);
  // Channel 0, 5 kHz frequency, 8-bit resolution
  ledcSetup(0, 5000, 8); 
}

void loop() {
  brightness += fadeDirection;

  // Reverse fade direction at limits
  if (brightness <= 0 || brightness >= 255) {
    fadeDirection = -fadeDirection;
  }

  ledcWrite(0, brightness);
  delay(5);
}