const int PWM_CHANNEL = 0;    // ESP32 has 16 channels which can generate 16 independent waveforms
const int PWM_FREQ = 500;     // Recall that Arduino Uno is ~490 Hz. Official ESP32 example uses 5,000Hz
const int PWM_RESOLUTION = 10; // We'll use same resolution as Uno (8 bits, 0-255) but ESP32 can go up to 16 bits 
const int LED_OUTPUT_PIN = 18;

const int PWM_CHANNEL2 = 0;    // ESP32 has 16 channels which can generate 16 independent waveforms
const int PWM_FREQ2 = 500;     // Recall that Arduino Uno is ~490 Hz. Official ESP32 example uses 5,000Hz
const int PWM_RESOLUTION2 = 10; // We'll use same resolution as Uno (8 bits, 0-255) but ESP32 can go up to 16 bits 
const int LED_OUTPUT_PIN2 = 26;

const int PWM_CHANNEL3 = 0;    // ESP32 has 16 channels which can generate 16 independent waveforms
const int PWM_FREQ3 = 500;     // Recall that Arduino Uno is ~490 Hz. Official ESP32 example uses 5,000Hz
const int PWM_RESOLUTION3 = 10; // We'll use same resolution as Uno (8 bits, 0-255) but ESP32 can go up to 16 bits 
const int LED_OUTPUT_PIN3 = 27;

// The max duty cycle value based on PWM resolution (will be 255 if resolution is 8 bits)
const int MAX_DUTY_CYCLE = (int)(pow(2, PWM_RESOLUTION) - 1); 

const int DELAY_MS = 100;  // delay between fade increments

bool first=1; //Nach erstem Durchlauf. Danach auf 0 setzen

void setup() {
  Serial.begin(9600);
  // Sets up a channel (0-15), a PWM duty cycle frequency, and a PWM resolution (1 - 16 bits) 
  // ledcSetup(uint8_t channel, double freq, uint8_t resolution_bits);
  //ledcSetup(PWM_CHANNEL, PWM_FREQ, PWM_RESOLUTION);
  // bool ledcAttach(uint8_t pin, uint32_t freq, uint8_t resolution);
  ledcAttach(LED_OUTPUT_PIN, PWM_FREQ, PWM_RESOLUTION);
  ledcAttach(LED_OUTPUT_PIN2, PWM_FREQ2, PWM_RESOLUTION2);
  ledcAttach(LED_OUTPUT_PIN3, PWM_FREQ3, PWM_RESOLUTION3);

  // ledcAttachPin(uint8_t pin, uint8_t channel);
  //ledcAttachPin(LED_OUTPUT_PIN, PWM_CHANNEL);
}

void loop() {

/*  // fade up PWM on given channel
  for(int dutyCycle = 0; dutyCycle <= MAX_DUTY_CYCLE; dutyCycle++){   
    ledcWrite(LED_OUTPUT_PIN, dutyCycle);
    ledcWrite(LED_OUTPUT_PIN2, dutyCycle);
    ledcWrite(LED_OUTPUT_PIN3, dutyCycle);
    
    Serial.println(LED_OUTPUT_PIN);
    Serial.println(dutyCycle);
    Serial.println(ledcRead(LED_OUTPUT_PIN));
    
    delay(DELAY_MS);
  }

  // fade down PWM on given channel
  for(int dutyCycle = MAX_DUTY_CYCLE; dutyCycle >= 0; dutyCycle--){
    ledcWrite(LED_OUTPUT_PIN, dutyCycle);
    ledcWrite(LED_OUTPUT_PIN2, dutyCycle);
    ledcWrite(LED_OUTPUT_PIN3, dutyCycle); 

    Serial.println(LED_OUTPUT_PIN);
    Serial.println(dutyCycle);
    Serial.println(ledcRead(LED_OUTPUT_PIN));

    delay(DELAY_MS);
  }
*/

if(first == 1){
    Serial.println(first);
    ledcWrite(LED_OUTPUT_PIN, 500);
    ledcWrite(LED_OUTPUT_PIN2, 500);
    ledcWrite(LED_OUTPUT_PIN3, 500);
    first=0;
    Serial.println(first);
}  
  //bool ledcFade(uint8_t pin, uint32_t start_duty, uint32_t target_duty, int max_fade_time_ms);
  
  for (int i=0; i <= 1023; i=((i+(i*0.1)+1))){
    Serial.println(i);
    ledcWrite(LED_OUTPUT_PIN, i);
    delay(DELAY_MS);
  }
  ledcWrite(LED_OUTPUT_PIN, 1023);
  delay(500);
  for (int i=1023; i >= 0; i=((i-(i*0.1)-1))){
    Serial.println(i);
    ledcWrite(LED_OUTPUT_PIN, i);
    delay(DELAY_MS);
  }
  ledcWrite(LED_OUTPUT_PIN, 0);
  Serial.println("Nach If, Vor Fade");
  //Serial.println(ledcFade(LED_OUTPUT_PIN, 500, 0, 20));
  Serial.println("Feda 500-0");
  delay(500);
  //ledcFade(LED_OUTPUT_PIN, 0, 1023, 2000);
  Serial.println("Feda 0-1023");
  delay(500);

}