ADC Class Reference

Analog-Digital conversion. More...

#include <cs_ADC.h>

Inheritance diagram for ADC:

Collaboration diagram for ADC:

Public Member Functions
cs_ret_code_t	init (const adc_config_t &config)
	Initialize ADC. More...
void	start ()
	Start the ADC sampling. More...
void	stop ()
	Stop the ADC sampling Only to be called from main thread. More...
void	setDoneCallback (adc_done_cb_t callback)
	Set the callback which is called when a buffer is filled. More...
void	setZeroCrossingCallback (adc_zero_crossing_cb_t callback)
	Set the callback which is called on a zero crossing interrupt. More...
void	enableZeroCrossingInterrupt (adc_channel_id_t channel, int32_t zeroVal)
	Enable zero crossing detection on given channel, generating interrupts. More...
cs_ret_code_t	changeChannel (adc_channel_id_t channel, adc_channel_config_t &config)
	Change channel config. More...
void	handleEvent (event_t &event)
	Handle events. More...
void	_restart ()
	Restart. More...
void	_handleAdcDone (adc_buffer_id_t bufIndex)
	Handle buffer, called in main thread. More...
void	_handleAdcLimitInterrupt (nrf_saadc_limit_t type)
	Called when the sampled value is above upper limit, or below lower limit. More...
void	_handleAdcInterrupt ()
	Handles the ADC interrupt. More...

Static Public Member Functions
static ADC &	getInstance ()
	Use static variant of singleton, no dynamic memory allocation. More...

Private Member Functions
	ADC ()
	Constructor. More...
	ADC (ADC const &)
void	operator= (ADC const &)
bool	dataCallbackRegistered ()
cs_ret_code_t	initSaadc ()
cs_ret_code_t	initChannel (adc_channel_id_t channel, adc_channel_config_t &config)
	Configure a channel. More...
void	setLimitUp ()
void	setLimitDown ()
cs_ret_code_t	initBufferQueue ()
cs_ret_code_t	fillSaadcQueue ()
	Try to add all queued buffers to the SAADC queue. More...
cs_ret_code_t	_fillSaadcQueue (bool fromInterrupt)
	Same as fillSaadcQueue(), but without critical region enter/exit. More...
cs_ret_code_t	addBufferToSaadcQueue (adc_buffer_id_t bufIndex)
	Puts a buffer in the SAADC queue. More...
cs_ret_code_t	_addBufferToSaadcQueue (adc_buffer_id_t bufIndex)
	Same as addBufferToSaadcQueue(), but without critical region enter/exit. More...
void	enterCriticalRegion ()
	Enter a region of code where variables are used that are also used in SAADC interrupts. More...
void	exitCriticalRegion ()
	Exit a region of code where variables are used that are also used in SAADC interrupts. More...
void	printQueues ()
void	applyConfig ()
Private Member Functions inherited from EventListener
	EventListener ()
virtual	~EventListener ()
	unregisters the listener. More...
virtual void	handleEvent (event_t &event)=0
	Handle events. More...
void	listen ()
	Registers this with the EventDispatcher. More...

Static Private Member Functions
static nrf_saadc_input_t	getAdcPin (adc_pin_id_t pinNum)
static nrf_ppi_channel_t	getPpiChannel (uint8_t index)
static nrf_saadc_event_t	getLimitLowEvent (adc_channel_id_t channel)
static nrf_saadc_event_t	getLimitHighEvent (adc_channel_id_t channel)
static nrf_gpiote_tasks_t	getGpioteTaskOut (uint8_t index)

Private Attributes
bool	_changeConfig = false
	Whether or not the config should be changed. More...
adc_config_t	_config
	Configuration of this class. More...
adc_channel_config_result_t	_channelResultConfigs [CS_ADC_NUM_CHANNELS]
	Resulting configuration of this class. More...
adc_buffer_seq_nr_t	_bufSeqNr = 1
	Buffer sequence number. More...
nrf_ppi_channel_t	_ppiChannelSample
	PPI channel to sample each tick, and count these. More...
nrf_ppi_channel_t	_ppiChannelStart
	PPI channel used to start the SAADC on end event. More...
CircularBuffer< adc_buffer_id_t >	_bufferQueue
	Queue of buffers that are free to be added to the SAADC queue. More...
CircularBuffer< adc_buffer_id_t >	_saadcBufferQueue
	Keeps up which buffers that are queued in the SAADC peripheral. More...
bool	_firstBuffer = true
adc_state_t	_state = ADC_STATE_IDLE
volatile adc_saadc_state_t	_saadcState = ADC_SAADC_STATE_IDLE
	Sate of the SAADC peripheral. More...
adc_done_cb_t	_doneCallback = nullptr
adc_zero_crossing_cb_t	_zeroCrossingCallback = nullptr
	The zero crossing callback. More...
adc_channel_id_t	_zeroCrossingChannel = 0
	The channel which is checked for zero crossings. More...
nrf_saadc_event_t	_eventLimitLow
	Cache limit event. More...
nrf_saadc_event_t	_eventLimitHigh
	Cache limit event. More...
bool	_zeroCrossingEnabled = false
	Keep up whether zero crossing is enabled. More...
uint32_t	_lastZeroCrossUpTime = 0
	Store the RTC timestamp of the last upwards zero crossing. More...
int32_t	_zeroValue = 0
	Store the zero value used to detect zero crossings. More...
int	_criticalRegionEntered = 0
	Keep up number of nested critical regions entered. More...

Detailed Description

Analog-Digital conversion.

The ADC class can be used to convert an analog signal to a digital value on multiple pins. It's currently used for power measurement (measure voltage and current).

There is only one SAADC hardware peripheral, hence this class conforms to the singleton design pattern.

The constructor does NOT have arguments you might expect, such as the number of buffers to use, or the size of the buffers. These are all set through preprocessor macros. The ADC class requires access to the following macros (see below).

The timer used to get new samples on regular time intervals. The timer should be able to run on at least 2kHz to be able to get the fine-grained current and voltage data we want.

• CS_ADC_TIMER The timer peripheral to use for the ADC peripheral.
• CS_ADC_INSTANCE_INDEX The instance id of the timer, used by nrf_drv_config.
• CS_ADC_TIMER_ID Number of the timer.

The buffers to be used internally. To have these buffers in the form of macros means that we can check at compile time if they are small enough with respect to the nRF52 memory limitations.

• CS_ADC_NUM_BUFFERS The number of ADC buffers to use, should be at least 2.
• CS_ADC_BUF_SIZE The size of the buffer (first time used in init()).

The pins:

• CS_ADC_MAX_PINS The maximum number of pins available for ADC.

The sequence of events can be found in the uml diagrams under docs.

Constructor & Destructor Documentation

ADC() [1/2]

ADC::ADC ( )

private

Constructor.

ADC() [2/2]

ADC::ADC ( ADC const &  )

private

Member Function Documentation

_addBufferToSaadcQueue()

cs_ret_code_t ADC::_addBufferToSaadcQueue ( adc_buffer_id_t  bufIndex )

private

Same as addBufferToSaadcQueue(), but without critical region enter/exit.

== Called from interrupt! ==

_fillSaadcQueue()

cs_ret_code_t ADC::_fillSaadcQueue ( bool  fromInterrupt )

private

Same as fillSaadcQueue(), but without critical region enter/exit.

Parameters

[in]

fromInterrupt

Whether this is called from an interrupt.

== Called from interrupt! ==

_handleAdcDone()

void ADC::_handleAdcDone

(

adc_buffer_id_t

bufIndex

)

Handle buffer, called in main thread.

_handleAdcInterrupt()

void ADC::_handleAdcInterrupt

(

)

Handles the ADC interrupt.

End:

• Restarts SAADC when no buffers are queued in SAADC,
• Fills up SAADC buffer.

_handleAdcLimitInterrupt()

void ADC::_handleAdcLimitInterrupt

(

nrf_saadc_limit_t

type

)

Called when the sampled value is above upper limit, or below lower limit.

_restart()

void ADC::_restart

(

)

Restart.

addBufferToSaadcQueue()

cs_ret_code_t ADC::addBufferToSaadcQueue ( adc_buffer_id_t  bufIndex )

private

Puts a buffer in the SAADC queue.

Starts the SAADC when it's idle. Waits (blocking) for the SAADC to be started to queue another buffer.

Returns

• ERR_SUCCESS when the buffer is queued in the SAADC.
• ERR_NO_SPACE when there are already enough buffers queued in the SAADC, so the given buffer is not queued.
• Other return codes for failures, the given buffer is not queued.

applyConfig()

void ADC::applyConfig ( )

private

changeChannel()

cs_ret_code_t ADC::changeChannel	(	adc_channel_id_t	channel,
		adc_channel_config_t &	config
	)

Change channel config.

Channel config will not change immediately.

Parameters

[in]	channel	Channel number.
[in]	config	The channel config.

Returns

Return code.

dataCallbackRegistered()

bool ADC::dataCallbackRegistered ( )

inlineprivate

enableZeroCrossingInterrupt()

void ADC::enableZeroCrossingInterrupt	(	adc_channel_id_t	channel,
		int32_t	zeroVal
	)

Enable zero crossing detection on given channel, generating interrupts.

Parameters

[in]	channel	The channel on which to check for zero crossings.
[in]	zeroVal	The value of zero.

enterCriticalRegion()

void ADC::enterCriticalRegion ( )

private

Enter a region of code where variables are used that are also used in SAADC interrupts.

Make sure you exit once for each time you call enter.

exitCriticalRegion()

void ADC::exitCriticalRegion ( )

private

Exit a region of code where variables are used that are also used in SAADC interrupts.

fillSaadcQueue()

cs_ret_code_t ADC::fillSaadcQueue ( )

private

Try to add all queued buffers to the SAADC queue.

If the SAADC queue is now filled, stop the timeout timer.

Returns

ERR_SUCCESS when SAADC queue is full, and timeout timer has been stopped.

ERR_WRONG_STATE when SAADC queue is not filled, and timeout timer has been stopped.

ERR_NOT_FOUND when the SAADC queue is not full, and timeout timer has not been stopped.

Other return codes on failure.

getAdcPin()

static nrf_saadc_input_t ADC::getAdcPin ( adc_pin_id_t  pinNum )

staticprivate

getGpioteTaskOut()

static nrf_gpiote_tasks_t ADC::getGpioteTaskOut ( uint8_t  index )

staticprivate

getInstance()

static ADC & ADC::getInstance ( )

inlinestatic

Use static variant of singleton, no dynamic memory allocation.

getLimitHighEvent()

static nrf_saadc_event_t ADC::getLimitHighEvent ( adc_channel_id_t  channel )

staticprivate

getLimitLowEvent()

static nrf_saadc_event_t ADC::getLimitLowEvent ( adc_channel_id_t  channel )

staticprivate

getPpiChannel()

static nrf_ppi_channel_t ADC::getPpiChannel ( uint8_t  index )

staticprivate

handleEvent()

void ADC::handleEvent ( event_t &  event )

virtual

Handle events.

This method is overloaded by all classes that derive from EventListener. They can receive an event_t struct and act upon it. These events are dispatched by the EventDispatcher.

Implements EventListener.

init()

cs_ret_code_t ADC::init

(

const adc_config_t &

config

)

Initialize ADC.

Parameters

[in]

config

Config struct.

Returns

Return code.

initBufferQueue()

cs_ret_code_t ADC::initBufferQueue ( )

private

initChannel()

cs_ret_code_t ADC::initChannel ( adc_channel_id_t  channel, adc_channel_config_t &  config  )

private

Configure a channel.

Parameters

[in]	channel	Channel number.
[in]	config	The channel config.

Returns

Return code.

initSaadc()

cs_ret_code_t ADC::initSaadc ( )

private

operator=()

void ADC::operator= ( ADC const &  )

private

printQueues()

void ADC::printQueues ( )

private

setDoneCallback()

void ADC::setDoneCallback

(

adc_done_cb_t

callback

)

Set the callback which is called when a buffer is filled.

Parameters

[in]

callback

Function to be called when a buffer is filled with samples.

setLimitDown()

void ADC::setLimitDown ( )

private

setLimitUp()

void ADC::setLimitUp ( )

private

setZeroCrossingCallback()

void ADC::setZeroCrossingCallback

(

adc_zero_crossing_cb_t

callback

)

Set the callback which is called on a zero crossing interrupt.

Currently only called when going from below to above the zero.

Parameters

[in]

callback

Function to be called on a zero crossing event. This function will run at interrupt level!

start()

void ADC::start

(

)

Start the ADC sampling.

stop()

void ADC::stop

(

)

Stop the ADC sampling Only to be called from main thread.

Member Data Documentation

_bufferQueue

CircularBuffer<adc_buffer_id_t> ADC::_bufferQueue

private

Queue of buffers that are free to be added to the SAADC queue.

== Used in interrupt! ==

_bufSeqNr

adc_buffer_seq_nr_t ADC::_bufSeqNr = 1

private

Buffer sequence number.

Increased each time a buffer is fully sampled.

_changeConfig

bool ADC::_changeConfig = false

private

Whether or not the config should be changed.

== Used in interrupt! ==

_channelResultConfigs

adc_channel_config_result_t ADC::_channelResultConfigs[CS_ADC_NUM_CHANNELS]

private

Resulting configuration of this class.

== Used in interrupt! ==

_config

adc_config_t ADC::_config

private

Configuration of this class.

== Used in interrupt! ==

_criticalRegionEntered

int ADC::_criticalRegionEntered = 0

private

Keep up number of nested critical regions entered.

_doneCallback

adc_done_cb_t ADC::_doneCallback = nullptr

private

_eventLimitHigh

nrf_saadc_event_t ADC::_eventLimitHigh

private

Cache limit event.

== Used in interrupt! ==

_eventLimitLow

nrf_saadc_event_t ADC::_eventLimitLow

private

Cache limit event.

== Used in interrupt! ==

_firstBuffer

bool ADC::_firstBuffer = true

private

_lastZeroCrossUpTime

uint32_t ADC::_lastZeroCrossUpTime = 0

private

Store the RTC timestamp of the last upwards zero crossing.

== Used in interrupt! ==

_ppiChannelSample

nrf_ppi_channel_t ADC::_ppiChannelSample

private

PPI channel to sample each tick, and count these.

Sample timer event COMPARE -> SAADC task SAMPLE -> Toggle sample test pin

_ppiChannelStart

nrf_ppi_channel_t ADC::_ppiChannelStart

private

PPI channel used to start the SAADC on end event.

SAADC event END -> SAADC task START

_saadcBufferQueue

CircularBuffer<adc_buffer_id_t> ADC::_saadcBufferQueue

private

Keeps up which buffers that are queued in the SAADC peripheral.

First buffer in queue is the one currently being (or going to be) filled with samples.

== Used in interrupt! ==

_saadcState

volatile adc_saadc_state_t ADC::_saadcState = ADC_SAADC_STATE_IDLE

private

Sate of the SAADC peripheral.

== Used in interrupt! ==

_state

adc_state_t ADC::_state = ADC_STATE_IDLE

private

_zeroCrossingCallback

adc_zero_crossing_cb_t ADC::_zeroCrossingCallback = nullptr

private

The zero crossing callback.

== Used in interrupt! ==

_zeroCrossingChannel

adc_channel_id_t ADC::_zeroCrossingChannel = 0

private

The channel which is checked for zero crossings.

== Used in interrupt! ==

_zeroCrossingEnabled

bool ADC::_zeroCrossingEnabled = false

private

Keep up whether zero crossing is enabled.

== Used in interrupt! ==

_zeroValue

int32_t ADC::_zeroValue = 0

private

Store the zero value used to detect zero crossings.

== Used in interrupt! ==

---

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

• source/include/drivers/cs_ADC.h