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PWM in ESP32

This piece of code demonstrates how to use PWM in ESP-IDF. For more information I recommend visiting the documentation because there are many details that you might need to read about yourself.

There are two primary types of PWM in ESP-IDF:

This snippet only demonstrates how to use LEDC. The documentation is an extremely good resource and you could write this on your own without any trouble. It really goes into detail about every thing.

Note: You may want to check the return values of ledc_timer_config or other functions casted to void. For the sake of simplicity I ignored their return values. Read the documentation for further information on how to handle errors.

 
        
#include "driver/ledc.h"
#include "freertos/FreeRTOS.h"

ledc_timer_config_t LED_TIMER = {
    .speed_mode = LEDC_HIGH_SPEED_MODE,
    .duty_resolution = LEDC_TIMER_8_BIT,
    .timer_num = LEDC_TIMER_0,
    .freq_hz = 1000,
    .clk_cfg = LEDC_AUTO_CLK,
    .deconfigure = false
};

ledc_channel_config_t LED_CONFIG = {
    .gpio_num = 18,                         // Use GPIO pin 18 (which supports PWM)
    .speed_mode = LEDC_HIGH_SPEED_MODE,
    .channel = LEDC_CHANNEL_0,
    .intr_type = LEDC_INTR_DISABLE,
    .timer_sel = LEDC_TIMER_0,
    .duty = 0,                              // max is 2^LEDTIMER.duty_resolution - 1
    .hpoint = 0                             // "delay" after which the counter starts.
};

const int32_t max_duty = 255; // alternatively pow(2, LED_TIMER.duty_resolution) - 1

void app_main() {
    (void)ledc_timer_config(&LED_TIMER);
    (void)ledc_channel_config(&LED_CONFIG);

    while (1) {
        for (int32_t duty = 0; duty <= max_duty; duty++) {
            (void)ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0,   duty);
            (void)ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0);
            vTaskDelay(pdMS_TO_TICKS(20));
        }
        for (uint32_t duty = max_duty; duty > 0; duty--) {
            (void)ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0, duty);
            (void)ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0);
            vTaskDelay(pdMS_TO_TICKS(20));
        }
    }
}