Skip to content

Latest commit

 

History

History
297 lines (187 loc) · 8.28 KB

ledc.rst

File metadata and controls

297 lines (187 loc) · 8.28 KB

LED Control (LEDC)

About

The LED control (LEDC) peripheral is primarily designed to control the intensity of LEDs, although it can also be used to generate PWM signals for other purposes.

ESP32 SoCs has from 6 to 16 channels (variates on socs, see table below) which can generate independent waveforms, that can be used for example to drive RGB LED devices.

ESP32 SoC Number of LEDC channels
ESP32 16
ESP32-S2 8
ESP32-S3 8
ESP32-C3 6
ESP32-C6 6
ESP32-H2 6

Arduino-ESP32 LEDC API

ledcAttach

This function is used to setup LEDC pin with given frequency and resolution. LEDC channel will be selected automatically.

bool ledcAttach(uint8_t pin, uint32_t freq, uint8_t resolution);
  • pin select LEDC pin.
  • freq select frequency of pwm.
  • resolution select resolution for LEDC channel.
    • range is 1-14 bits (1-20 bits for ESP32).

This function will return true if configuration is successful. If false is returned, error occurs and LEDC channel was not configured.

ledcAttachChannel

This function is used to setup LEDC pin with given frequency, resolution and channel.

bool ledcAttachChannel(uint8_t pin, uint32_t freq, uint8_t resolution, int8_t channel);
  • pin select LEDC pin.
  • freq select frequency of pwm.
  • resolution select resolution for LEDC channel.
    • range is 1-14 bits (1-20 bits for ESP32).
  • channel select LEDC channel.

This function will return true if configuration is successful. If false is returned, error occurs and LEDC channel was not configured.

ledcWrite

This function is used to set duty for the LEDC pin.

bool ledcWrite(uint8_t pin, uint32_t duty);
  • pin select LEDC pin.
  • duty select duty to be set for selected LEDC pin.

This function will return true if setting duty is successful. If false is returned, error occurs and duty was not set.

ledcRead

This function is used to get configured duty for the LEDC pin.

uint32_t ledcRead(uint8_t pin);
  • pin select LEDC pin to read the configured LEDC duty.

This function will return duty set for selected LEDC pin.

ledcReadFreq

This function is used to get configured frequency for the LEDC channel.

uint32_t ledcReadFreq(uint8_t pin);
  • pin select LEDC pin to read the configured frequency.

This function will return frequency configured for selected LEDC pin.

ledcWriteTone

This function is used to setup the LEDC pin to 50 % PWM tone on selected frequency.

uint32_t ledcWriteTone(uint8_t pin, uint32_t freq);
  • pin select LEDC pin.
  • freq select frequency of pwm signal. If frequency is 0, duty will be set to 0.

This function will return frequency set for LEDC pin. If 0 is returned, error occurs and LEDC pin was not configured.

ledcWriteNote

This function is used to setup the LEDC pin to specific note.

uint32_t ledcWriteNote(uint8_t pin, note_t note, uint8_t octave);
  • pin select LEDC pin.
  • note select note to be set.
NOTE_C NOTE_Cs NOTE_D NOTE_Eb NOTE_E NOTE_F
NOTE_Fs NOTE_G NOTE_Gs NOTE_A NOTE_Bb NOTE_B
  • octave select octave for note.

This function will return frequency configured for the LEDC pin according to note and octave inputs. If 0 is returned, error occurs and the LEDC channel was not configured.

ledcDetach

This function is used to detach the pin from LEDC.

bool ledcDetach(uint8_t pin);
  • pin select LEDC pin.

This function returns true if detaching was successful. If false is returned, an error occurred and the pin was not detached.

ledcChangeFrequency

This function is used to set frequency for the LEDC pin.

uint32_t ledcChangeFrequency(uint8_t pin, uint32_t freq, uint8_t resolution);
  • pin select LEDC pin.
  • freq select frequency of pwm.
  • resolution select resolution for LEDC channel.
    • range is 1-14 bits (1-20 bits for ESP32).

This function will return frequency configured for the LEDC channel. If 0 is returned, error occurs and the LEDC channel frequency was not set.

ledcOutputInvert

This function is used to set inverting output for the LEDC pin.

bool ledcOutputInvert(uint8_t pin, bool out_invert);
  • pin select LEDC pin.
  • out_invert select, if output should be inverted (true = inverting output).

This function returns true if setting inverting output was successful. If false is returned, an error occurred and the inverting output was not set.

ledcFade

This function is used to setup and start fade for the LEDC pin.

bool ledcFade(uint8_t pin, uint32_t start_duty, uint32_t target_duty, int max_fade_time_ms);
  • pin select LEDC pin.
  • start_duty select starting duty of fade.
  • target_duty select target duty of fade.
  • max_fade_time_ms select maximum time for fade.

This function will return true if configuration is successful. If false is returned, error occurs and LEDC fade was not configured / started.

ledcFadeWithInterrupt

This function is used to setup and start fade for the LEDC pin with interrupt.

bool ledcFadeWithInterrupt(uint8_t pin, uint32_t start_duty, uint32_t target_duty, int max_fade_time_ms, void (*userFunc)(void));
  • pin select LEDC pin.
  • start_duty select starting duty of fade.
  • target_duty select target duty of fade.
  • max_fade_time_ms select maximum time for fade.
  • userFunc function to be called when interrupt is triggered.

This function will return true if configuration is successful and fade start. If false is returned, error occurs and LEDC fade was not configured / started.

ledcFadeWithInterruptArg

This function is used to setup and start fade for the LEDC pin with interrupt using arguments.

bool ledcFadeWithInterruptArg(uint8_t pin, uint32_t start_duty, uint32_t target_duty, int max_fade_time_ms, void (*userFunc)(void*), void * arg);
  • pin select LEDC pin.
  • start_duty select starting duty of fade.
  • target_duty select target duty of fade.
  • max_fade_time_ms select maximum time for fade.
  • userFunc function to be called when interrupt is triggered.
  • arg pointer to the interrupt arguments.

This function will return true if configuration is successful and fade start. If false is returned, error occurs and LEDC fade was not configured / started.

analogWrite

This function is used to write an analog value (PWM wave) on the pin. It is compatible with Arduinos analogWrite function.

void analogWrite(uint8_t pin, int value);
  • pin select the GPIO pin.
  • value select the duty cycle of pwm. * range is from 0 (always off) to 255 (always on).

analogWriteResolution

This function is used to set resolution for selected analogWrite pin.

void analogWriteResolution(uint8_t pin, uint8_t resolution);
  • pin select the GPIO pin.
  • resolution select resolution for analog channel.

analogWriteFrequency

This function is used to set frequency for selected analogWrite pin.

void analogWriteFrequency(uint8_t pin, uint32_t freq);
  • pin select the GPIO pin.
  • freq select frequency of pwm.

Example Applications

LEDC fade example:

.. literalinclude:: ../../../libraries/ESP32/examples/AnalogOut/LEDCFade/LEDCFade.ino
    :language: arduino

LEDC software fade example:

.. literalinclude:: ../../../libraries/ESP32/examples/AnalogOut/LEDCSoftwareFade/LEDCSoftwareFade.ino
    :language: arduino

LEDC Write RGB example:

.. literalinclude:: ../../../libraries/ESP32/examples/AnalogOut/ledcWrite_RGB/ledcWrite_RGB.ino
    :language: arduino