Chapter 2. API Reference
• ESP_ERR_INVALID_ARG Parameter error
• ESP_FAIL Can not find a proper pre-divider number base on the given frequency and the current
duty_resolution.
Parameters
• timer_conf: Pointer of LEDC timer configure struct
esp_err_t ledc_update_duty(ledc_mode_t speed_mode, ledc_channel_t channel)
LEDC update channel parameters.
Note Call this function to activate the LEDC updated parameters. After ledc_set_duty, we need to call this
function to update the settings.
Note ledc_set_duty, ledc_set_duty_with_hpoint and ledc_update_duty are not thread-safe, do not call these
functions to control one LEDC channel in different tasks at the same time. A thread-safe version of API
is ledc_set_duty_and_update
Return
• ESP_OK Success
• ESP_ERR_INVALID_ARG Parameter error
Parameters
• speed_mode: Select the LEDC channel group with specified speed mode. Note that not all targets
support high speed mode.
• channel: LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
esp_err_t ledc_set_pin(int gpio_num, ledc_mode_t speed_mode, ledc_channel_t ledc_channel)
Set LEDC output gpio.
Return
• ESP_OK Success
• ESP_ERR_INVALID_ARG Parameter error
Parameters
• gpio_num: The LEDC output gpio
• speed_mode: Select the LEDC channel group with specified speed mode. Note that not all targets
support high speed mode.
• ledc_channel: LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
esp_err_t ledc_stop(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t idle_level)
LEDC stop. Disable LEDC output, and set idle level.
Return
• ESP_OK Success
• ESP_ERR_INVALID_ARG Parameter error
Parameters
• speed_mode: Select the LEDC channel group with specified speed mode. Note that not all targets
support high speed mode.
• channel: LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
• idle_level: Set output idle level after LEDC stops.
esp_err_t ledc_set_freq(ledc_mode_t speed_mode, ledc_timer_t timer_num, uint32_t freq_hz)
LEDC set channel frequency (Hz)
Return
• ESP_OK Success
• ESP_ERR_INVALID_ARG Parameter error
• ESP_FAIL Can not find a proper pre-divider number base on the given frequency and the current
duty_resolution.
Parameters
• speed_mode: Select the LEDC channel group with specified speed mode. Note that not all targets
support high speed mode.
• timer_num: LEDC timer index (0-3), select from ledc_timer_t
• freq_hz: Set the LEDC frequency
uint32_t ledc_get_freq(ledc_mode_t speed_mode, ledc_timer_t timer_num)
LEDC get channel frequency (Hz)
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