#include <stdio.h>
#include "driver/ledc.h"
#include "esp_err.h"

// ------------------------------------------------------------------------
// ISSUE: In low speed mode only, the PWM frequency at the output is 1/10th
// of the defined frequency when set to 979 Hz or higher at 10-bit resolution. 
// Note: 1/978 = 1023 (10-bit)

#define LEDC_FREQUENCY     (979) // Frequency in Hertz
#define LEDC_MODE          LEDC_LOW_SPEED_MODE
//#define LEDC_MODE          LEDC_HIGH_SPEED_MODE
// -----------------------------------------------------------------------

#define LEDC_TIMER         LEDC_TIMER_0
#define LEDC_OUTPUT_IO     (19) // Define the output GPIO
#define LEDC_CHANNEL       LEDC_CHANNEL_0
#define LEDC_DUTY          (511) // Set duty to 50%

static void example_ledc_init(void)
{
  // Prepare and then apply the LEDC PWM timer configuration
  ledc_timer_config_t ledc_timer = {
    .speed_mode       = LEDC_LOW_SPEED_MODE,
    .duty_resolution  = LEDC_TIMER_10_BIT,
    .timer_num        = LEDC_TIMER,
    .freq_hz          = LEDC_FREQUENCY,
    .clk_cfg          = LEDC_AUTO_CLK
  };
  ESP_ERROR_CHECK(ledc_timer_config(&ledc_timer));

  // Prepare and then apply the LEDC PWM channel configuration
  ledc_channel_config_t ledc_channel = {
    .gpio_num       = LEDC_OUTPUT_IO,
    .speed_mode     = LEDC_MODE,
    .channel        = LEDC_CHANNEL,
    .intr_type      = LEDC_INTR_DISABLE,
    .timer_sel      = LEDC_TIMER,
    .duty           = 0, // Set duty to 0%
    .hpoint         = 0,
    .flags = {
      .output_invert = 0
    }
  };
  ESP_ERROR_CHECK(ledc_channel_config(&ledc_channel));

  // Set duty to 50% and update
  ESP_ERROR_CHECK(ledc_set_duty(LEDC_MODE, LEDC_CHANNEL, LEDC_DUTY));
  ESP_ERROR_CHECK(ledc_update_duty(LEDC_MODE, LEDC_CHANNEL));
}

void setup() {
  example_ledc_init();
}

void loop() {
}