Example Code for Arduino - PWM Output (Basic Tutorial)

Hardware Preparation

FireBeetle 2 ESP32-S3 AI Board with OV2640 Camera x 1

Software Preparation

When you use the ESP32 for the first time, you need to know the following steps:

1. Add the ESP32 development board in Arduino IDE (How to add the ESP32 board to Arduino IDE?)

2. Select the development board and serial port

3. Burn the program

Basic APIs

The PWM function of ESP32-S3 needs to be declared in advance.

• ledcSetup(Channel, freq, resolution)

  • Description: set the PWM signal properties

  • Parameter:

    • LedChannel: the channel that generates PWM signal

    • freq: PWM frequency

    • resolution: PWM resolution

• ledcAttachPin(GPIO, Channel)

  • Description: specify which GPIO the signal will appear upon

  • Parameter:

    • GPIO: the GPIO that will output the signal

    • Channel: the channel that will generate the signal

• ledcWrite(Channel, dutyCycle)

  • Description:output PWM signal

  • Parameter:

    • Channel: the channel that generates PWM signal

    • dutyCycle: PWM value

Sample Code

/*LED fading example 
 * 
 */
const int ledPin = 21;  // Actual LED pin for outputting PWM signal 

//Setting PWM properties
const int freq = 5000;//PWM frequence 
const int ledChannel = 0;//Channel that generates pwm signal 
const int resolution = 8;//8-bit resolution 

void setup(){
  //Configure LED PWM functionalitites
  ledcSetup(ledChannel, freq, resolution);

  //Attach the channel to the GPIO to be controlled
  ledcAttachPin(ledPin, ledChannel);
}

void loop(){
  //LED fade in 
  for(int dutyCycle = 0; dutyCycle <= 255; dutyCycle++){   
    // changing the LED brightness with PWM
    ledcWrite(ledChannel, dutyCycle);
    delay(15);
  }

  //LED fade off
  for(int dutyCycle = 255; dutyCycle >= 0; dutyCycle--){
    // changing the LED brightness with PWM
    ledcWrite(ledChannel, dutyCycle);   
    delay(15);
  }
}