// use 8 bit precision for LEDC timer
#define LEDC_TIMER_8_BIT 8

// use 5000 Hz as a LEDC base frequency
#define LEDC_BASE_FREQ 5000

// LED pins
#define LED_PIN_1 4
 
// LED channel that will be used instead of automatic selection.
#define LEDC_CHANNEL 0

int brightness = 0;  // how bright the LED is
int fadeAmount = 5;  // how many points to fade the LED by

void setup() {
  // Use single LEDC channel 0 for both pins
  ledcAttachChannel(LED_PIN_1, LEDC_BASE_FREQ, LEDC_TIMER_8_BIT, LEDC_CHANNEL);
 }

void loop() {
  // set the brightness on LEDC channel 0
  ledcWriteChannel(LEDC_CHANNEL, brightness);

  // change the brightness for next time through the loop:
  brightness = brightness + fadeAmount;

  // reverse the direction of the fading at the ends of the fade:
  if (brightness <= 0 || brightness >= 255) {
    fadeAmount = -fadeAmount;
  }
  // wait for 30 milliseconds to see the dimming effect
  delay(30);
}