esp32_LED_fade.ino

/*
 LEDC Software Fade

 This example shows how to software fade LED
 using the ledcWrite function.

 
 */

 // use first channel of 16 channels (started from zero)
#define LEDC_CHANNEL_0     0

// use 13 bit precission for LEDC timer
#define LEDC_TIMER_13_BIT  13

// use 5000 Hz as a LEDC base frequency
#define LEDC_BASE_FREQ     5000

// fade LED PIN (replace with LED_BUILTIN constant for built-in LED)
#define LED_PIN            2

int brightness = 0;    // how bright the LED is
int fadeAmount = 5;    // how many points to fade the LED by

// Arduino like analogWrite
// value has to be between 0 and valueMax
void ledcAnalogWrite(uint8_t channel, uint32_t value, uint32_t valueMax = 255) {
    // calculate duty, 8191 from 2 ^ 13 - 1
    uint32_t duty = (8191 / valueMax) * min(value, valueMax);

    // write duty to LEDC
    ledcWrite(channel, duty);
}

void setup() {
    // Setup timer and attach timer to a led pin
    ledcSetup(LEDC_CHANNEL_0, LEDC_BASE_FREQ, LEDC_TIMER_13_BIT);
    ledcAttachPin(LED_PIN, LEDC_CHANNEL_0);
}

void loop() {
    // set the brightness on LEDC channel 0
    ledcAnalogWrite(LEDC_CHANNEL_0, brightness);

    // change the brightness for next time through the loop:
    brightness = brightness + fadeAmount;

    // reverse the direction of the fading at the ends of the fade:
    if (brightness <= 0 || brightness >= 255) {
        fadeAmount = -fadeAmount;
    }
    // wait for 30 milliseconds to see the dimming effect
    delay(30);
}