ESP32 LEDC provider for PWM like output on GPIO pins. More...

#include <Esp32Ledc.hxx>

Classes
class	Channel

Public Member Functions
	Esp32Ledc (const std::initializer_list< uint8_t > &pins, const ledc_channel_t first_channel=LEDC_CHANNEL_0, const ledc_timer_bit_t timer_resolution=LEDC_TIMER_12_BIT, const uint32_t timer_hz=5000, const ledc_timer_t timer_num=LEDC_TIMER_0, const ledc_mode_t timer_mode=LEDC_LOW_SPEED_MODE, const ledc_clk_cfg_t timer_clock=LEDC_AUTO_CLK)
	Constructor.

void	hw_init ()
	Initializes the LEDC peripheral.

PWM *	get_channel (unsigned id)

void	fade_channel_over_time (unsigned id, uint32_t target_duty=0, uint32_t fade_period=1000, ledc_fade_mode_t fade_mode=LEDC_FADE_NO_WAIT)
	Transitions a PWM output from the current duty to the target duty over the provided time period.

Static Public Member Functions
static void	ledc_fade_setup ()
	Static entry point for configuring the LEDC hardware fade controller.

Private Member Functions
void	set_period (uint32_t counts)
	Set PWM period.

uint32_t	get_period ()
	Get PWM period.

void	set_duty (ledc_channel_t channel, uint32_t counts)
	Sets the duty cycle.

uint32_t	get_duty (ledc_channel_t channel)
	Gets the duty cycle.

uint32_t	get_period_max ()
	Get max period supported by the underlying LEDC timer.

uint32_t	get_period_min ()
	Get min period supported by the underlying LEDC timer.

	DISALLOW_COPY_AND_ASSIGN (Esp32Ledc)

Private Attributes
const ledc_channel_t	firstChannel_
	First LEDC Channel for this Esp32Ledc.

ledc_timer_config_t	timerConfig_
	LEDC Timer configuration settings.

uninitialized< Channel >	channels_ [LEDC_CHANNEL_MAX]
	PWM instances connected to LEDC channels.

std::vector< uint8_t >	pins_
	Collection of GPIO pins in use by this Esp32Ledc.

Static Private Attributes
static pthread_once_t	ledcFadeOnce_
	Protects the initialization of LEDC Fade ISR hook.

Detailed Description

ESP32 LEDC provider for PWM like output on GPIO pins.

This class allows creation of up to eight PWM outputs using a single PWM frequency. All outputs in a single Esp32Ledc instance will share the same PWM frequency and will be assigned a channel sequentially.

When the more than one PWM frequency is needed for outputs it is required to create multiple Esp32Ledc instances, each with a unique LEDC timer (LEDC_TIMER_0 through LEDC_TIMER_3) and a unique first channel (LED_CHANNEL_0 through LED_CHANNEL_5 or LED_CHANNEL_7 depending on ESP32 variant).

The ESP32-C3 only supports six channels, whereas other variants support eight. Creating more than one Esp32Ledc instance will not increase the number of outputs.

Example of usage:

OpenMRN openmrn(NODE_ID);
Esp32Ledc ledc({16,    // Channel 0
                17,    // Channel 1
                18});  // Channel 2
ServoConsumer servo_0(openmrn.stack()->node(), cfg.seg().servo(), 1000,
                      ledc.get_channel(1));
PWMGPO led_0(ledc.get_channel(0), 2500, 0);
void setup() {
  ...
  ledc.hw_init();
  openmrn.begin();
  openmrn.stack()->set_tx_activity_led(&led_0);
  ledc.fade_channel_over_time(2, 2500, SEC_TO_MSEC(5));
  ...
}

Definition at line 82 of file Esp32Ledc.hxx.

Constructor & Destructor Documentation

◆ Esp32Ledc()

openmrn_arduino::Esp32Ledc::Esp32Ledc	(	const std::initializer_list< uint8_t > &	pins,
		const ledc_channel_t	first_channel = `LEDC_CHANNEL_0`,
		const ledc_timer_bit_t	timer_resolution = `LEDC_TIMER_12_BIT`,
		const uint32_t	timer_hz = `5000`,
		const ledc_timer_t	timer_num = `LEDC_TIMER_0`,
		const ledc_mode_t	timer_mode = `LEDC_LOW_SPEED_MODE`,
		const ledc_clk_cfg_t	timer_clock = `LEDC_AUTO_CLK`
	)

inline

Constructor.

Parameters

pins	is the collection of output pins to use for this instance.
first_channel	is the first LEDC channel to use for this Esp32Ledc instance, default is LEDC_CHANNEL_0.
timer_resolution	is the resolution of the LEDC timer, default is 12bit.
timer_hz	is the LEDC timer tick frequency, default is 5kHz.
timer_num	is the LEDC timer to use, default is LEDC_TIMER_0.
timer_mode	is the LED timer mode to use, default is LEDC_LOW_SPEED_MODE.
timer_clock	is the LEDC timer clock source, default is LEDC_AUTO_CLK.

Note: For

Parameters

timer_mode an additional value of LEDC_HIGH_SPEED_MODE is supported ONLY on the base ESP32 variant. Other variants of the ESP32 only support LEDC_LOW_SPEED_MODE.

Definition at line 102 of file Esp32Ledc.hxx.

Member Function Documentation

◆ fade_channel_over_time()

void openmrn_arduino::Esp32Ledc::fade_channel_over_time	(	unsigned	id,
		uint32_t	target_duty = `0`,
		uint32_t	fade_period = `1000`,
		ledc_fade_mode_t	fade_mode = `LEDC_FADE_NO_WAIT`
	)

inline

Transitions a PWM output from the current duty to the target duty over the provided time period.

Parameters

id	is the output number, zero based for this Esp32Ledc instance.
target_duty	target duty value, default is zero.
fade_period	number of milliseconds to use for the transition, default is 1000 milliseconds.
fade_mode	controls if this call is blocking or non-blocking, default is non-blocking.

NOTE: One a fade request has been submitted to the hardware it can not be canceled and no other requests can be submitted or processed until the previous request has completed.

Definition at line 185 of file Esp32Ledc.hxx.

◆ get_channel()

PWM * openmrn_arduino::Esp32Ledc::get_channel ( unsigned id )

inline

Returns: one PWM output.

Parameters

id	is the output number, zero based for this Esp32Ledc instance.

Definition at line 165 of file Esp32Ledc.hxx.

◆ get_duty()

uint32_t openmrn_arduino::Esp32Ledc::get_duty ( ledc_channel_t channel )

inlineprivate

Gets the duty cycle.

Parameters

channel PWM channel to retrieve the duty cycle for.

Returns: counts duty cycle in counts

Definition at line 287 of file Esp32Ledc.hxx.

◆ get_period()

uint32_t openmrn_arduino::Esp32Ledc::get_period ( )

inlineprivate

Get PWM period.

Returns: PWM timer frequency in Hz.

Definition at line 269 of file Esp32Ledc.hxx.

◆ get_period_max()

uint32_t openmrn_arduino::Esp32Ledc::get_period_max ( )

inlineprivate

Get max period supported by the underlying LEDC timer.

Returns: period in counts.

Definition at line 294 of file Esp32Ledc.hxx.

◆ get_period_min()

uint32_t openmrn_arduino::Esp32Ledc::get_period_min ( )

inlineprivate

Get min period supported by the underlying LEDC timer.

Returns: period in counts.

Definition at line 301 of file Esp32Ledc.hxx.

◆ hw_init()

void openmrn_arduino::Esp32Ledc::hw_init ( )

inline

Initializes the LEDC peripheral.

Parameters

pins	are the gpio pins to assign to the LEDC channels.

NOTE: Depending on the target ESP32 device the number of LEDC channels available will be either six or eight. Exceeding this number of pins will generate a runtime failure.

Definition at line 132 of file Esp32Ledc.hxx.

◆ ledc_fade_setup()

static void openmrn_arduino::Esp32Ledc::ledc_fade_setup ( )

inlinestatic

Static entry point for configuring the LEDC hardware fade controller.

NOTE: This method should not be invoked by the user code, it will be called automatically the first time fade_channel_over_time is called on any instance of Esp32Ledc.

Definition at line 203 of file Esp32Ledc.hxx.

◆ set_duty()

void openmrn_arduino::Esp32Ledc::set_duty	(	ledc_channel_t	channel,
		uint32_t	counts
	)

inlineprivate

Sets the duty cycle.

Parameters

channel	PWM channel to configure
counts	duty cycle in counts

Definition at line 277 of file Esp32Ledc.hxx.

◆ set_period()

void openmrn_arduino::Esp32Ledc::set_period ( uint32_t counts )

inlineprivate

Set PWM period.

Parameters

counts PWM timer frequency in Hz.

NOTE: This will apply to ALL PWM outputs that use the same timer.

Definition at line 260 of file Esp32Ledc.hxx.

Member Data Documentation

◆ channels_

uninitialized<Channel> openmrn_arduino::Esp32Ledc::channels_[LEDC_CHANNEL_MAX]

private

PWM instances connected to LEDC channels.

Definition at line 316 of file Esp32Ledc.hxx.

◆ firstChannel_

const ledc_channel_t openmrn_arduino::Esp32Ledc::firstChannel_

private

First LEDC Channel for this Esp32Ledc.

Definition at line 307 of file Esp32Ledc.hxx.

◆ ledcFadeOnce_

pthread_once_t openmrn_arduino::Esp32Ledc::ledcFadeOnce_

staticprivate

Protects the initialization of LEDC Fade ISR hook.

Definition at line 313 of file Esp32Ledc.hxx.

◆ pins_

std::vector<uint8_t> openmrn_arduino::Esp32Ledc::pins_

private

Collection of GPIO pins in use by this Esp32Ledc.

Definition at line 319 of file Esp32Ledc.hxx.

◆ timerConfig_

ledc_timer_config_t openmrn_arduino::Esp32Ledc::timerConfig_

private

LEDC Timer configuration settings.

Definition at line 310 of file Esp32Ledc.hxx.

The documentation for this class was generated from the following file:

Esp32Ledc.hxx

Classes

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Esp32Ledc()

Member Function Documentation

◆ fade_channel_over_time()

◆ get_channel()

◆ get_duty()

◆ get_period()

◆ get_period_max()

◆ get_period_min()

◆ hw_init()

◆ ledc_fade_setup()

◆ set_duty()

◆ set_period()

Member Data Documentation

◆ channels_

◆ firstChannel_

◆ ledcFadeOnce_

◆ pins_

◆ timerConfig_