// the number of the LED pin
const int ledPin = 9;  // PIN16

// setting PWM properties
const int freq = 40000;//頻率40khz,目前測試到50HZ都正常
const int ledChannel = 0;//通道0,共有0~16
const int resolution = 8;//分辨率8bit
int PWM;

int VRpin = 17;
int VR;

void setup() {
  // configure LED PWM functionalitites
  ledcSetup(ledChannel, freq, resolution);//設置 通道,頻率,分辨率

  // attach the channel to the GPIO to be controlled
  ledcAttachPin(ledPin, ledChannel);//使用pwm的腳位及通道

  pinMode(VRpin, INPUT);
}

void loop() {
  // increase the LED brightness
  VR = analogRead(VRpin);
  Serial.print("VR:");
  Serial.println(VR);
  PWM = map(VR, 0, 1024, 0, 255);
  Serial.print("PWM:");
  Serial.println(PWM);
  ledcWrite(ledChannel, PWM);//通道及工作週期50%
}