PWMDriverESP32 Class Reference

Audio output to PWM pins for the ESP32. The ESP32 supports up to 16 channels. More...

#include <PWMDriverESP32.h>

Inheritance diagram for PWMDriverESP32:

Public Member Functions
	PWMDriverESP32 ()
PWMConfig &	audioInfo ()
virtual int	availableForWrite ()
bool	begin (PWMConfig cfg)
virtual PWMConfig	defaultConfig ()
virtual int	effectiveOutputSampleRate ()
	Provides the effective sample rate.
virtual void	end ()
uint32_t	framesPerSecond ()
bool	isTimerStarted ()
void	logPins ()
virtual void	pwmWrite (int channel, int value)
void	setBuffer (BaseBuffer< uint8_t > *buffer)
virtual void	setupPWM ()
	Setup LED PWM.
virtual void	setupTimer ()
	Setup ESP32 timer with callback.
virtual void	startTimer ()
uint32_t	underflowsPerSecond ()
void	updateStatistics ()
virtual size_t	write (const uint8_t *data, size_t len)

Protected Member Functions
virtual int	decimation ()
	Decimation factor to reduce the sample rate.
void	deleteBuffer ()
float	frequency (int resolution)
	determiens the PWM frequency based on the requested resolution
virtual bool	isDecimateActive ()
virtual int	maxChannels ()
virtual int	maxOutputValue ()
	provides the max value for the configured resulution
virtual int	maxSampleRate ()
	Provides the max working sample rate.
int	maxUnsignedValue (int resolution)
	provides the max value for the indicated resulution
virtual int	nextValue ()
	determines the next scaled value
void	playNextFrame ()
	writes the next frame to the output pins

Static Protected Member Functions
static void	pwm_callback (void *ptr)
	timer callback: write the next frame to the pins

Protected Attributes
AudioInfo	actual_info
uint32_t	actual_timer_frequency = 0
PWMConfig	audio_config
BaseBuffer< uint8_t > *	buffer = nullptr
Decimate	decimate
int	decimation_factor = 0
uint32_t	frame_count = 0
uint32_t	frame_size = 0
uint32_t	frames_per_second = 0
bool	is_blocking_write = true
bool	is_timer_started = false
Vector< PinInfo >	pins
uint32_t	time_1_sec
TimerAlarmRepeating	timer
uint32_t	underflow_count = 0
uint32_t	underflow_per_second = 0

Detailed Description

Audio output to PWM pins for the ESP32. The ESP32 supports up to 16 channels.

Author

Phil Schatzmann

Copyright

GPLv3

Constructor & Destructor Documentation

PWMDriverESP32()

PWMDriverESP32 ( )

inline

Member Function Documentation

audioInfo()

PWMConfig & audioInfo ( )

inlineinherited

availableForWrite()

virtual int availableForWrite ( )

inlinevirtualinherited

begin()

bool begin ( PWMConfig  cfg )

inlineinherited

decimation()

virtual int decimation ( )

inlineprotectedvirtualinherited

Decimation factor to reduce the sample rate.

Reimplemented in PWMDriverRenesas.

defaultConfig()

virtual PWMConfig defaultConfig ( )

inlinevirtualinherited

Reimplemented in PWMDriverRenesas.

deleteBuffer()

void deleteBuffer ( )

inlineprotectedinherited

effectiveOutputSampleRate()

virtual int effectiveOutputSampleRate ( )

inlinevirtualinherited

Provides the effective sample rate.

end()

virtual void end ( )

inlinevirtual

Reimplemented from DriverPWMBase.

framesPerSecond()

uint32_t framesPerSecond ( )

inlineinherited

frequency()

float frequency ( int  resolution )

inlineprotected

determiens the PWM frequency based on the requested resolution

isDecimateActive()

virtual bool isDecimateActive ( )

inlineprotectedvirtualinherited

The requested sampling rate is too hight: we only process half of the samples so we can half the sampling rate

isTimerStarted()

bool isTimerStarted ( )

inlineinherited

logPins()

void logPins ( )

inline

maxChannels()

virtual int maxChannels ( )

inlineprotectedvirtual

Implements DriverPWMBase.

maxOutputValue()

virtual int maxOutputValue ( )

inlineprotectedvirtual

provides the max value for the configured resulution

Implements DriverPWMBase.

maxSampleRate()

virtual int maxSampleRate ( )

inlineprotectedvirtualinherited

Provides the max working sample rate.

Reimplemented in PWMDriverRenesas.

maxUnsignedValue()

int maxUnsignedValue ( int  resolution )

inlineprotected

provides the max value for the indicated resulution

nextValue()

virtual int nextValue ( )

inlineprotectedvirtualinherited

determines the next scaled value

playNextFrame()

void playNextFrame ( )

inlineprotectedinherited

writes the next frame to the output pins

pwm_callback()

static void pwm_callback ( void *  ptr )

inlinestaticprotected

timer callback: write the next frame to the pins

pwmWrite()

virtual void pwmWrite ( int  channel, int  value  )

inlinevirtual

write a pwm value to the indicated channel. The max value depends on the resolution

Implements DriverPWMBase.

setBuffer()

void setBuffer ( BaseBuffer< uint8_t > *  buffer )

inlineinherited

You can assign your own custom buffer impelementation: must be allocated on the heap and will be cleaned up by this class

setupPWM()

virtual void setupPWM ( )

inlinevirtual

Setup LED PWM.

Implements DriverPWMBase.

setupTimer()

virtual void setupTimer ( )

inlinevirtual

Setup ESP32 timer with callback.

Implements DriverPWMBase.

startTimer()

virtual void startTimer ( )

inlinevirtual

when we get the first write -> we activate the timer to start with the output of data

Implements DriverPWMBase.

underflowsPerSecond()

uint32_t underflowsPerSecond ( )

inlineinherited

updateStatistics()

void updateStatistics ( )

inlineinherited

write()

virtual size_t write ( const uint8_t *  data, size_t  len  )

inlinevirtualinherited

Member Data Documentation

actual_info

AudioInfo actual_info

protectedinherited

actual_timer_frequency

uint32_t actual_timer_frequency = 0

protected

audio_config

PWMConfig audio_config

protectedinherited

buffer

BaseBuffer<uint8_t>* buffer = nullptr

protectedinherited

decimate

Decimate decimate

protectedinherited

decimation_factor

int decimation_factor = 0

protectedinherited

frame_count

uint32_t frame_count = 0

protectedinherited

frame_size

uint32_t frame_size = 0

protectedinherited

frames_per_second

uint32_t frames_per_second = 0

protectedinherited

is_blocking_write

bool is_blocking_write = true

protectedinherited

is_timer_started

bool is_timer_started = false

protectedinherited

pins

Vector<PinInfo> pins

protected

time_1_sec

uint32_t time_1_sec

protectedinherited

timer

TimerAlarmRepeating timer

protected

underflow_count

uint32_t underflow_count = 0

protectedinherited

underflow_per_second

uint32_t underflow_per_second = 0

protectedinherited

---

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

• src/AudioTools/CoreAudio/AudioPWM/PWMDriverESP32.h