esp-pwm/main/esp-pwm.c

#include <stdio.h>
#include <math.h>

#include "driver/ledc.h"
#include "hal/ledc_types.h"
#include "soc/clk_tree_defs.h"
#include "esp_clk_tree.h"
#include "esp_log.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

const char* TAG = "MAIN_CPP";

void app_main() {
    ESP_LOGI(TAG, "BOOT\n");

    const uint32_t timer_freq = 2731;

    uint32_t clk_freq = 0;
    ESP_ERROR_CHECK(esp_clk_tree_src_get_freq_hz(SOC_MOD_CLK_RC_FAST, ESP_CLK_TREE_SRC_FREQ_PRECISION_EXACT, &clk_freq));

    uint32_t duty_resolution = ledc_find_suitable_duty_resolution(clk_freq, timer_freq);
    if (duty_resolution == 0) {
        ESP_LOGE(TAG, "Could not determine optimal duty resolution.\n");
        return;
    }

    ledc_timer_config_t ledc_config = {
        .speed_mode = LEDC_LOW_SPEED_MODE,
        .timer_num = LEDC_TIMER_0,
        .freq_hz = timer_freq,
        .duty_resolution = duty_resolution,
        .clk_cfg = LEDC_USE_RC_FAST_CLK
    };

    ESP_ERROR_CHECK(ledc_timer_config(&ledc_config));

    ledc_channel_config_t ledc_ch_config = {
        .gpio_num = 9,
        .speed_mode = LEDC_LOW_SPEED_MODE,
        .channel = LEDC_CHANNEL_0,
        .timer_sel = LEDC_TIMER_0,
        .duty = (uint32_t) (pow(2, duty_resolution) / 2),
        // .hpoint = ((uint32_t) pow(2, duty_resolution)) - 1,
        .hpoint = 0,
        .sleep_mode = LEDC_SLEEP_MODE_KEEP_ALIVE,
        .flags.output_invert = false
    };

    ESP_ERROR_CHECK(ledc_channel_config(&ledc_ch_config));

    while (true) {
        vTaskDelay(10000);   
    }
}