#define led 32
int brightness = 0;
int fade_amount = 5;

void setup() {
  // put your setup code here, to run once:
  ledcAttachPin(led,0);
  ledcSetup(0,4000,8);

}

void loop() {
  // put your main code here, to run repeatedly:
  ledcWrite(0,brightness);
  brightness=brightness+fade_amount;
  if(brightness<=0||brightness>=255){
    fade_amount = -fade_amount;
  }
  delay(50);
}