#define PIN_LED 2 //define the led pin
#define CHN 0 //define the pwm channel
#define FRQ 1000 //define the pwm frequency
#define PWM_BIT 8 //define the pwm precision
void setup() {
 ledcAttachChannel(PIN_LED, FRQ, PWM_BIT, CHN); //attach the led pin to pwm channel
}
void loop() {
 for (int i = 0; i < 255; i++) { //make light fade in
 ledcWrite(PIN_LED, i);
 delay(10);
 }
 for (int i = 255; i > -1; i--) { //make light fade out
 ledcWrite(PIN_LED, i);
 delay(10);
 }
}