PWMDriverZephyr Class Reference

Audio output to PWM pins for Zephyr RTOS. More...

#include <PWMDriverZephyr.h>

Inheritance diagram for PWMDriverZephyr:

Public Member Functions
	PWMDriverZephyr ()=default
PWMConfig &	audioInfo ()
virtual int	availableForWrite ()
bool	begin (PWMConfig cfg)
virtual PWMConfig	defaultConfig ()
virtual int	effectiveOutputSampleRate ()
	Provides the effective sample rate.
virtual void	end () override
	Ends PWM output.
uint32_t	framesPerSecond ()
bool	isTimerStarted ()
void	setBuffer (BaseBuffer< uint8_t > *buffer)
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 ()
virtual bool	isDecimateActive ()
virtual int	maxChannels () override
	Maximum supported PWM channels.
virtual int	maxOutputValue () override
	Maximum output value (resolution-dependent)
virtual int	maxSampleRate ()
	Provides the max working sample rate.
virtual int	nextValue ()
	determines the next scaled value
void	playNextFrame ()
	writes the next frame to the output pins
virtual void	pwmWrite (int channel, int value) override
	Write PWM value to a specific channel.
virtual void	setupPWM () override
	Setup PWM pins and devices.
virtual void	setupTimer () override
	Configure timer parameters (called after setupPWM)
virtual void	startTimer () override
	Start the timer for periodic playback.

Static Protected Member Functions
static void	defaultPWMAudioOutputCallback (void *obj)
	Timer callback: invoked periodically to write the next audio frame.

Protected Attributes
AudioInfo	actual_info
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
uint32_t	period_ns = 0
uint32_t	time_1_sec
AudioTimer	timer
uint32_t	underflow_count = 0
uint32_t	underflow_per_second = 0

Detailed Description

Audio output to PWM pins for Zephyr RTOS.

Author

Phil Schatzmann

Copyright

GPLv3

Supports PWM audio output on Zephyr targets using the native PWM driver API. Manages multiple PWM channels with configurable frequency and resolution.

Characteristics:

• Uses Zephyr's PWM driver API (pwm_set_dt, pwm_get_cycles_per_sec)
• Supports multiple channels via channel configuration
• Callback-based playback using AudioTimer
• Automatic pin management

Constructor & Destructor Documentation

PWMDriverZephyr()

PWMDriverZephyr ( )

default

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.

defaultPWMAudioOutputCallback()

static void defaultPWMAudioOutputCallback ( void *  obj )

inlinestaticprotected

Timer callback: invoked periodically to write the next audio frame.

deleteBuffer()

void deleteBuffer ( )

inlineprotectedinherited

effectiveOutputSampleRate()

virtual int effectiveOutputSampleRate ( )

inlinevirtualinherited

Provides the effective sample rate.

end()

virtual void end ( )

inlineoverridevirtual

Ends PWM output.

Reimplemented from PWMDriverBase.

framesPerSecond()

uint32_t framesPerSecond ( )

inlineinherited

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

maxChannels()

virtual int maxChannels ( )

inlineoverrideprotectedvirtual

Maximum supported PWM channels.

Implements PWMDriverBase.

maxOutputValue()

virtual int maxOutputValue ( )

inlineoverrideprotectedvirtual

Maximum output value (resolution-dependent)

Implements PWMDriverBase.

maxSampleRate()

virtual int maxSampleRate ( )

inlineprotectedvirtualinherited

Provides the max working sample rate.

Reimplemented in PWMDriverRenesas.

nextValue()

virtual int nextValue ( )

inlineprotectedvirtualinherited

determines the next scaled value

playNextFrame()

void playNextFrame ( )

inlineprotectedinherited

writes the next frame to the output pins

pwmWrite()

virtual void pwmWrite ( int  channel, int  value  )

inlineoverrideprotectedvirtual

Write PWM value to a specific channel.

Implements PWMDriverBase.

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 ( )

inlineoverrideprotectedvirtual

Setup PWM pins and devices.

Implements PWMDriverBase.

setupTimer()

virtual void setupTimer ( )

inlineoverrideprotectedvirtual

Configure timer parameters (called after setupPWM)

Implements PWMDriverBase.

startTimer()

virtual void startTimer ( )

inlineoverrideprotectedvirtual

Start the timer for periodic playback.

Implements PWMDriverBase.

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

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

period_ns

uint32_t period_ns = 0

protected

time_1_sec

uint32_t time_1_sec

protectedinherited

timer

AudioTimer 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/PWMDriverZephyr.h