#define LED1 19
#define LED2 18
#define LED3 15

const int pinChannel0 = 0;
const int pinChannel1 = 1;
const int pinChannel2 = 2;
const int freq = 1000;
const int resolution = 8;
int value_PWM;

void setup(){
  Serial.begin(115200);
  ledcSetup(pinChannel0, freq, resolution);
  ledcSetup(pinChannel1, freq, resolution);
  ledcSetup(pinChannel2, freq, resolution);

  ledcAttachPin(LED1, pinChannel0);
  ledcAttachPin(LED2, pinChannel1);
  ledcAttachPin(LED3, pinChannel2);
}

void loop() { 
for (value_PWM=0; value_PWM<255; value_PWM++) { 
  ledcWrite(pinChannel0, value_PWM); 
  ledcWrite(pinChannel1, (value_PWM-2)); 
  ledcWrite(pinChannel2, (value_PWM-2));
   Serial.println(value_PWM); 
   delay(20);
   } 
   
   for(value_PWM=255; value_PWM>0;value_PWM--){
    ledcWrite(pinChannel0,value_PWM); 
    ledcWrite(pinChannel1, (value_PWM+1));
    ledcWrite(pinChannel2, (value_PWM+7));
    Serial.println(value_PWM);
    delay(20);
   }
}