PWMDriverSTM32 Class Reference

Audio output to PWM pins for STM32. We use one timer to generate the sample rate and one timer for the PWM signal. More...

#include <PWMDriverSTM32.h>

Inheritance diagram for PWMDriverSTM32:

Public Member Functions
	PWMDriverSTM32 ()
PWMConfig &	audioInfo ()
virtual int	availableForWrite ()
bool	begin (PWMConfig cfg)
virtual PWMConfig	defaultConfig ()
virtual int	effectiveOutputSampleRate ()
	Provides the effective sample rate.
virtual void	end () override
uint32_t	framesPerSecond ()
bool	isTimerStarted ()
void	setBuffer (BaseBuffer< uint8_t > *buffer)
void	setPWMTimer (HardwareTimer &t)
	Defines the timer which is used to generate the PWM signal.
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 ()
	One timer supports max 4 output pins.
virtual int	maxOutputValue ()
	provides the max value for the configured resulution
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)
virtual void	setupPWM ()
	Setup PWM Pins.
virtual void	setupTimer ()
virtual void	startTimer () override

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

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
int64_t	max_value
HardwareTimer *	p_pwm_timer = nullptr
PWM	pwm
TimerAlarmRepeating	ticker
uint32_t	time_1_sec
uint32_t	underflow_count = 0
uint32_t	underflow_per_second = 0

Detailed Description

Audio output to PWM pins for STM32. We use one timer to generate the sample rate and one timer for the PWM signal.

Author

Phil Schatzmann

Copyright

GPLv3

Constructor & Destructor Documentation

PWMDriverSTM32()

PWMDriverSTM32 ( )

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.

defaultPWMAudioOutputCallback()

static void defaultPWMAudioOutputCallback ( void *  obj )

inlinestaticprotected

timer callback: write the next frame to the pins

deleteBuffer()

void deleteBuffer ( )

inlineprotectedinherited

effectiveOutputSampleRate()

virtual int effectiveOutputSampleRate ( )

inlinevirtualinherited

Provides the effective sample rate.

end()

virtual void end ( )

inlineoverridevirtual

Reimplemented from DriverPWMBase.

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 ( )

inlineprotectedvirtual

One timer supports max 4 output pins.

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.

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  )

inlineprotectedvirtual

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

setPWMTimer()

void setPWMTimer ( HardwareTimer &  t )

inline

Defines the timer which is used to generate the PWM signal.

setupPWM()

virtual void setupPWM ( )

inlineprotectedvirtual

Setup PWM Pins.

Implements DriverPWMBase.

setupTimer()

virtual void setupTimer ( )

inlineprotectedvirtual

Implements DriverPWMBase.

startTimer()

virtual void startTimer ( )

inlineoverrideprotectedvirtual

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

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

max_value

int64_t max_value

protected

p_pwm_timer

HardwareTimer* p_pwm_timer = nullptr

protected

pwm

PWM pwm

protected

ticker

TimerAlarmRepeating ticker

protected

time_1_sec

uint32_t time_1_sec

protectedinherited

underflow_count

uint32_t underflow_count = 0

protectedinherited

underflow_per_second

uint32_t underflow_per_second = 0

protectedinherited

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

• src/AudioTools/CoreAudio/AudioPWM/PWMDriverSTM32.h