void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  ledcSetup(0, 30000, 10);  //pwm频道, 频率, 精度
  ledcSetup(1, 30000, 10);  //pwm频道, 频率, 精度
  ledcSetup(2, 30000, 10);  //pwm频道, 频率, 精度
  ledcAttachPin(15, 0);
  ledcAttachPin(16, 1);
  ledcAttachPin(17, 2);
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
}