Overview

The MCUXpresso SDK provides a peripheral driver for the 12-bit Cyclic Analog-to-Digital Converter (CADC) module of MCUXpresso SDK devices.

The analog-to-digital (ADC) converter function consists of two separate analog-to-digital converters, each with eight analog inputs and its own sample and hold circuit. A common digital control module configures and controls the functioning of the converters.

To match the hardware feature, the CADC driver is designed with three parts: APIs for configuring common digital control module, APIs for configuring each converter and APIs for operating sample slots.

The common digital control configuration is set when initializing the CADC module in application, as it should be done firstly before any other operation, and decide how the two converters work together. The converter configure APIs would set each converter's attributes and operate them. Finally, the sample slot API would configure the sample slot with input channel and gather them to be a conversion sequence. Once the trigger (software trigger or external hardware trigger) starts, the sequence is started and the conversion are executed.

Function groups

Initialization and deinitialization

This function group initializes/de-initializes the CADC. The initialization should be done first, before any operation to the CADC module in application. It enables the clock and sets the configuration for the common digital control. An API to fill the configuration with an available default setting is also provided.

Each converter

This function group configures each of the two converters in the CADC module.

Each sample

This function group is for the operations to sample slot.

Typical use case

Triggered parallel

Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/cadc

Data Structures
struct	cadc_config_t
	Defines the structure for configuring the CyclicADC's common setting. More...

struct	cadc_converter_config_t
	Define the structure for configuring each converter. More...

struct	cadc_sample_config_t
	Defines the structure for configuring the sample slot. More...

Macros
#define	CADC_SAMPLE_MASK(index) (1U << (index))
	Convert index to mask for sample slot. More...

Enumerations
enum	_cadc_status_flags { kCADC_ZeroCrossingFlag = (1U << 0U), kCADC_HighLimitFlag = (1U << 2U), kCADC_LowLimitFlag = (1U << 1U), kCADC_ConverterAInProgressFlag = (1U << 3U), kCADC_ConverterBInProgressFlag = (1U << 4U), kCADC_ConverterAEndOfScanFlag = (1U << 5U), kCADC_ConverterBEndOfScanFlag = (1U << 6U), kCADC_ConverterAPowerDownFlag = (1U << 7U), kCADC_ConverterBPowerDownFlag = (1U << 8U) }
	CADC status flags. More...

enum	_cadc_interrupt_enable { kCADC_ZeroCrossingInterruptEnable = (1U << 0U), kCADC_HighLimitInterruptEnable = (1U << 1U), kCADC_LowLimitInterruptEnable = (1U << 2U), kCADC_ConverterAEndOfScanInterruptEnable = (1U << 3U), kCADC_ConverterBEndOfScanInterruptEnable = (1U << 4U) }
	CADC Interrupts. More...

enum	_cadc_converter_id { kCADC_ConverterA = (1U << 0U), kCADC_ConverterB = (1U << 1U) }
	CADC Converter identifier. More...

enum	cadc_dual_converter_scan_mode_t { kCADC_DualConverterWorkAsOnceSequential = 0U, kCADC_DualConverterWorkAsOnceParallel = 1U, kCADC_DualConverterWorkAsLoopSequential = 2U, kCADC_DualConverterWorkAsLoopParallel = 3U, kCADC_DualConverterWorkAsTriggeredSequential = 4U, kCADC_DualConverterWorkAsTriggeredParallel = 5U }
	Defines the enumeration for dual converter's scan mode. More...

enum	cadc_dma_trigger_source_t { kCADC_DMATriggerSourceAsEndOfScan = 0U, kCADC_DMATriggerSourceAsSampleReady = 1U }
	Defines the enumeration for DMA trigger's source. More...

enum	cadc_reference_voltage_source_t { kCADC_ReferenceVoltageVrefPad = 0U, kCADC_ReferenceVoltageChannelPad = 1U }
	Defines the enumeration for converter's reference voltage source. More...

enum	cadc_channel_gain_t { kCADC_ChannelGainx1 = 0U, kCADC_ChannelGainx2 = 1U, kCADC_ChannelGainx4 = 2U }
	Defines the enumeration for channel's input gain. More...

enum	cadc_speed_mode_t { kCADC_SpeedMode0 = 0U, kCADC_SpeedMode1 = 1U, kCADC_SpeedMode2 = 2U, kCADC_SpeedMode3 = 3U }
	Defines the enumeration for the converter's speed mode. More...

enum	cadc_zero_crossing_mode_t { kCADC_ZeroCorssingDisabled = 0U, kCADC_ZeroCorssingForPtoNSign = 1U, kCADC_ZeroCorssingForNtoPSign = 2U, kCADC_ZeroCorssingForAnySignChanged = 3U }
	Defines the enumeration for the sample slot's zero crossing event. More...

enum	cadc_idle_work_mode_t { kCADC_IdleKeepNormal = 0U, kCADC_IdleAutoStandby, kCADC_IdleAutoPowerDown }
	Defines the enumeration for converter's work mode in idle mode. More...

Driver version
#define	FSL_CADC_DRIVER_VERSION (MAKE_VERSION(2, 0, 0))
	CADC driver version 2.0.0. More...

Initialization and deinitialization
void	CADC_Init (ADC_Type base, const cadc_config_t config)
	Initializes the CADC module. More...

void	CADC_GetDefaultConfig (cadc_config_t *config)
	Gets an available pre-defined settings for module's configuration. More...

void	CADC_Deinit (ADC_Type *base)
	Deinitializes the CADC module. More...

Each Converter
void	CADC_SetConverterConfig (ADC_Type base, uint16_t converterMask, const cadc_converter_config_t config)
	Configures the converter. More...

void	CADC_GetDefaultConverterConfig (cadc_converter_config_t *config)
	Gets an available pre-defined settings for each converter's configuration. More...

void	CADC_EnableConverter (ADC_Type *base, uint16_t converterMask, bool enable)
	Enables the converter's conversion. More...

void	CADC_EnableConverterSyncInput (ADC_Type *base, uint16_t converterMask, bool enable)
	Enables the input of external sync signal. More...

void	CADC_EnableConverterPower (ADC_Type *base, uint16_t converterMask, bool enable)
	Enables power for the converter. More...

void	CADC_DoSoftwareTriggerConverter (ADC_Type *base, uint16_t converterMask)
	Triggers the converter by software trigger. More...

void	CADC_EnableConverterDMA (ADC_Type *base, uint16_t converterMask, bool enable)
	Enables the DMA feature. More...

void	CADC_EnableInterrupts (ADC_Type *base, uint16_t mask)
	Enables the interrupts. More...

void	CADC_DisableInterrupts (ADC_Type *base, uint16_t mask)
	Disables the interrupts. More...

uint16_t	CADC_GetStatusFlags (ADC_Type *base)
	Gets the status flags. More...

void	CADC_ClearStatusFlags (ADC_Type *base, uint16_t flags)
	Clears the status flags. More...

Each Sample
void	CADC_SetSampleConfig (ADC_Type base, uint16_t sampleIndex, const cadc_sample_config_t config)
	Configures the sample slot. More...

static void	CADC_EnableSample (ADC_Type *base, uint16_t sampleMask, bool enable)
	Enables the sample slot. More...

static void	CADC_EnableSampleResultReadyInterrupts (ADC_Type *base, uint16_t sampleMask, bool enable)
	Enables the interrupt for each sample slot when its result is ready. More...

static uint16_t	CADC_GetSampleReadyStatusFlags (ADC_Type *base)
	Returns the sample ready flags of sample slots. More...

static uint16_t	CADC_GetSampleLowLimitStatusFlags (ADC_Type *base)
	Gets the low limit flags of sample slots. More...

static void	CADC_ClearSampleLowLimitStatusFlags (ADC_Type *base, uint16_t sampleMask)
	Clears low limit flags of sample slots. More...

static uint16_t	CADC_GetSampleHighLimitStatusFlags (ADC_Type *base)
	Gets the high limit flags of sample slots. More...

static void	CADC_ClearSampleHighLimitStatusFlags (ADC_Type *base, uint16_t sampleMask)
	Clears the high limit flags of sample slots. More...

static uint16_t	CADC_GetSampleZeroCrossingStatusFlags (ADC_Type *base)
	Gets the zero crossing flags of sample slots. More...

static void	CADC_ClearSampleZeroCrossingStatusFlags (ADC_Type *base, uint16_t sampleMask)
	Clears zero crossing flags of sample slots. More...

static uint16_t	CADC_GetSampleResultValue (ADC_Type *base, uint16_t sampleIndex)
	Gets the sample result value. More...

Data Structure Documentation

struct cadc_config_t

Data Fields
cadc_dual_converter_scan_mode_t	dualConverterScanMode
	Dual converter's scan mode. More...

bool	enableSimultaneousMode
	Using Simultaneous mode. More...

cadc_dma_trigger_source_t	DMATriggerSoruce
	DMA trigger source. More...

cadc_idle_work_mode_t	idleWorkMode
	Converter's work mode when in idle. More...

uint16_t	powerUpDelay
	Delay clock count to wait for the clock is stable. More...

Field Documentation

cadc_dual_converter_scan_mode_t cadc_config_t::dualConverterScanMode

bool cadc_config_t::enableSimultaneousMode

cadc_dma_trigger_source_t cadc_config_t::DMATriggerSoruce

cadc_idle_work_mode_t cadc_config_t::idleWorkMode

uint16_t cadc_config_t::powerUpDelay

Available range is 0-63.

struct cadc_converter_config_t

Data Fields
uint16_t	clockDivisor
	Converter's clock divisor for the clock source. More...

cadc_speed_mode_t	speedMode
	Converter's speed mode. More...

cadc_reference_voltage_source_t	highReferenceVoltageSource
	High voltage reference source. More...

cadc_reference_voltage_source_t	lowReferenceVoltageSource
	Low reference voltage source. More...

uint16_t	sampleWindowCount
	Sample Window Count. More...

Field Documentation

uint16_t cadc_converter_config_t::clockDivisor

Available setting range is 0-63.

cadc_speed_mode_t cadc_converter_config_t::speedMode

cadc_reference_voltage_source_t cadc_converter_config_t::highReferenceVoltageSource

cadc_reference_voltage_source_t cadc_converter_config_t::lowReferenceVoltageSource

uint16_t cadc_converter_config_t::sampleWindowCount

Available setting range is 0-7.

struct cadc_sample_config_t

Data Fields
uint16_t	channelNumber
	Channel number. More...

bool	enableDifferentialPair
	Use differential sample input or not. More...

cadc_channel_gain_t	channelGain
	Input gain. More...

cadc_zero_crossing_mode_t	zeroCrossingMode
	Zero crossing mode. More...

uint16_t	highLimitValue
	High limit value. More...

uint16_t	lowLimitValue
	Low limit value. More...

uint16_t	offsetValue
	Offset value. More...

bool	enableWaitSync
	Wait for sync input to launch this sample's conversion. More...

Field Documentation

uint16_t cadc_sample_config_t::channelNumber

The available range is 0-15.

bool cadc_sample_config_t::enableDifferentialPair

cadc_channel_gain_t cadc_sample_config_t::channelGain

cadc_zero_crossing_mode_t cadc_sample_config_t::zeroCrossingMode

uint16_t cadc_sample_config_t::highLimitValue

Original value formation as hardware register, with 3-bits left shifted.

uint16_t cadc_sample_config_t::lowLimitValue

Original value formation as hardware register, with 3-bits left shifted.

uint16_t cadc_sample_config_t::offsetValue

Original value formation as hardware register, with 3-bits left shifted.

bool cadc_sample_config_t::enableWaitSync

Macro Definition Documentation

#define FSL_CADC_DRIVER_VERSION (MAKE_VERSION(2, 0, 0))

#define CADC_SAMPLE_MASK ( index ) (1U << (index))

Enumeration Type Documentation

enum _cadc_status_flags

Enumerator
kCADC_ZeroCrossingFlag	Zero crossing.
kCADC_HighLimitFlag	High limit.
kCADC_LowLimitFlag	Low limit.
kCADC_ConverterAInProgressFlag	Conversion in progress, converter A.
kCADC_ConverterBInProgressFlag	Conversion in progress, converter B.
kCADC_ConverterAEndOfScanFlag	End of scan, converter A.
kCADC_ConverterBEndOfScanFlag	End of scan, converter B.
kCADC_ConverterAPowerDownFlag	The converter is powered down, converter A.
kCADC_ConverterBPowerDownFlag	The converter is powered down, converter B.

enum _cadc_interrupt_enable

Enumerator
kCADC_ZeroCrossingInterruptEnable	Zero crossing interrupt.
kCADC_HighLimitInterruptEnable	High limit interrupt.
kCADC_LowLimitInterruptEnable	Low limit interrupt.
kCADC_ConverterAEndOfScanInterruptEnable	End of scan interrupt, converter A.
kCADC_ConverterBEndOfScanInterruptEnable	End of scan interrupt, converter B.

enum _cadc_converter_id

Enumerator
kCADC_ConverterA	Converter A.
kCADC_ConverterB	Converter B.

enum cadc_dual_converter_scan_mode_t

Enumerator
kCADC_DualConverterWorkAsOnceSequential	Once (single) sequential.
kCADC_DualConverterWorkAsOnceParallel	Once parallel.
kCADC_DualConverterWorkAsLoopSequential	Loop sequential.
kCADC_DualConverterWorkAsLoopParallel	Loop parallel.
kCADC_DualConverterWorkAsTriggeredSequential	Triggered sequential.
kCADC_DualConverterWorkAsTriggeredParallel	Triggered parallel.

enum cadc_dma_trigger_source_t

Enumerator
kCADC_DMATriggerSourceAsEndOfScan	DMA trigger source is end of scan interrupt.
kCADC_DMATriggerSourceAsSampleReady	DMA trigger source is RDY bits.

enum cadc_reference_voltage_source_t

Enumerator
kCADC_ReferenceVoltageVrefPad	VREF pin.
kCADC_ReferenceVoltageChannelPad	ANx2 or ANx3 pin.

enum cadc_channel_gain_t

Enumerator
kCADC_ChannelGainx1	Gain x1.
kCADC_ChannelGainx2	Gain x2.
kCADC_ChannelGainx4	Gain x4.

enum cadc_speed_mode_t

Enumerator
kCADC_SpeedMode0	Conversion clock frequency <= 6.25 MHz; current consumption per converter = 6 mA.
kCADC_SpeedMode1	Conversion clock frequency <= 12.25 MHz; current consumption per converter = 10.8 mA.
kCADC_SpeedMode2	Conversion clock frequency <= 18.75 MHz; current consumption per converter = 18 mA.
kCADC_SpeedMode3	Conversion clock frequency <= 25 MHz; current consumption per converter = 25.2 mA.

enum cadc_zero_crossing_mode_t

Enumerator
kCADC_ZeroCorssingDisabled	Zero Crossing disabled.
kCADC_ZeroCorssingForPtoNSign	Zero Crossing enabled for positive to negative sign change.
kCADC_ZeroCorssingForNtoPSign	Zero Crossing enabled for negative to positive sign change.
kCADC_ZeroCorssingForAnySignChanged	Zero Crossing enabled for any sign change.

enum cadc_idle_work_mode_t

Enumerator
kCADC_IdleKeepNormal	Keep normal.
kCADC_IdleAutoStandby	Fall into standby mode automatically.
kCADC_IdleAutoPowerDown	Fall into power down mode automatically.

Function Documentation

void CADC_Init	(	ADC_Type *	base,
		const cadc_config_t *	config
	)

This function is to make the initialization for using CADC module. The operations are:

Enable the clock for CADC.
Set the global settings for CADC converter.

Parameters

base	CADC peripheral base address.
config	Pointer to configuration structure. See "cadc_config_t".

void CADC_GetDefaultConfig ( cadc_config_t * config )

This function initializes the module's configuration structure with an available settings. The default value are:

*   config->dualConverterScanMode = kCADC_DualConverterWorkAsTriggeredParallel;
*   config->enableSimultaneousMode = true;
*   config->DMATriggerSoruce = kCADC_DMATriggerSourceAsEndOfScan;
*   config->idleWorkMode = kCADC_IdleKeepNormal;
*   config->powerUpDelay = 26U;
* 

Parameters

config Pointer to configuration structure. See "cadc_config_t"

void CADC_Deinit ( ADC_Type * base )

This function is to make the de-initialization for using CADC module. The operations are:

Power down both converter.
Disable the clock for CADC.

Parameters

base	CADC peripheral base address.

void CADC_SetConverterConfig	(	ADC_Type *	base,
		uint16_t	converterMask,
		const cadc_converter_config_t *	config
	)

Parameters

base	CADC peripheral base address.
converterMask	Mask for converters to be configured. See "_cadc_converter_id".
config	Pointer to configuration structure. See "cadc_converter_config_t".

void CADC_GetDefaultConverterConfig ( cadc_converter_config_t * config )

This function initializes each converter's configuration structure with an available settings. The default value are:

*   config->clockDivisor = 4U;
*   config->speedMode = kCADC_SpeedMode0;
*   config->highReferenceVoltageSource = kCADC_ReferenceVoltageVrefPad;
*   config->lowReferenceVoltageSource = kCADC_ReferenceVoltageVrefPad;
*   config->sampleWindowCount = 0U;
* 

Parameters

config Pointer to configuration structure. See "cadc_converter_config_t"

void CADC_EnableConverter	(	ADC_Type *	base,
		uint16_t	converterMask,
		bool	enable
	)

This function is to enable the converter's conversion. The conversion should only be launched after the converter is enabled. When this feature is asserted to be "false", the current scan is stopped and no further scans can start. All the software trigger and hardware trigger are ignored.

Parameters

base	CADC peripheral base address.
converterMask	Mask for converters to be operated. See "_cadc_converter_id".
enable	Enable the power for converter.

void CADC_EnableConverterSyncInput	(	ADC_Type *	base,
		uint16_t	converterMask,
		bool	enable
	)

This function is to enable the input of external sync signal. The external sync signal could be used to trigger the conversion if the hardware trigger related setting is used. Note: When in "Once" scan mode, this gate would be off automatically after an available sync is received. User needs to enable the input again manually if another sync signal is wanted.

Parameters

base	CADC peripheral base address.
converterMask	Mask for converters to be operated. See "_cadc_converter_id".
enable	Enable the feature or not.

void CADC_EnableConverterPower	(	ADC_Type *	base,
		uint16_t	converterMask,
		bool	enable
	)

This function is to enable the power for the converter. The converter should be powered on before conversion. Once this API is called, the converter would be powered on after a few moment (so-called power up delay), so that the power would be stable.

Parameters

base	CADC peripheral base address.
converterMask	Mask for converters to be operated. See "_cadc_converter_id".
enable	Enable the feature or not.

void CADC_DoSoftwareTriggerConverter	(	ADC_Type *	base,
		uint16_t	converterMask
	)

This function is to do the software trigger to the converter. The software trigger can used to start a conversion sequence.

Parameters

base	CADC peripheral base address.
converterMask	Mask for converters to be operated. See "_cadc_converter_id".

void CADC_EnableConverterDMA	(	ADC_Type *	base,
		uint16_t	converterMask,
		bool	enable
	)

Parameters

base	CADC peripheral base address.
converterMask	Mask for converters to be operated. See "_cadc_converter_id".
enable	Enable the feature or not.

void CADC_EnableInterrupts	(	ADC_Type *	base,
		uint16_t	mask
	)

Parameters

base	CADC peripheral base address.
mask	Mask value for interrupt events. See "_cadc_interrupt_enable".

void CADC_DisableInterrupts	(	ADC_Type *	base,
		uint16_t	mask
	)

Parameters

base	CADC peripheral base address.
mask	Mask value for interrupt events. See "_cadc_interrupt_enable".

uint16_t CADC_GetStatusFlags ( ADC_Type * base )

Parameters

base	CADC peripheral base address.

Returns: Mask value for the event flags. See "_cadc_status_flags".

void CADC_ClearStatusFlags	(	ADC_Type *	base,
		uint16_t	flags
	)

Parameters

base	CADC peripheral base address.
flags	Mask value for the event flags to be cleared. See "_cadc_status_flags".

void CADC_SetSampleConfig	(	ADC_Type *	base,
		uint16_t	sampleIndex,
		const cadc_sample_config_t *	config
	)

Parameters

base	CADC peripheral base address.
sampleIndex	Index of sample slot in conversion sequence. Available range is 0-15.
config	Pointer to configuration structure. See "cadc_sample_config_t"

static void CADC_EnableSample	(	ADC_Type *	base,
		uint16_t	sampleMask,
		bool	enable
	)

inlinestatic

This function is to enable the sample slot. Only the enabled sample slot can join the conversion sequence.

Parameters

base	CADC peripheral base address.
sampleMask	Mask value of sample slots in conversion sequence. Each bit is responding to a sample slot.
enable	Enable the feature or not.

static void CADC_EnableSampleResultReadyInterrupts	(	ADC_Type *	base,
		uint16_t	sampleMask,
		bool	enable
	)

inlinestatic

Parameters

base	CADC peripheral base address.
sampleMask	Mask value of sample slots in conversion sequence. Each bit is responding to a sample slot.
enable	Enable the feature or not.

static uint16_t CADC_GetSampleReadyStatusFlags ( ADC_Type * base )

inlinestatic

Parameters

base	CADC peripheral base address.

Returns: Mask value for the sample slots if their result are ready.

static uint16_t CADC_GetSampleLowLimitStatusFlags ( ADC_Type * base )

inlinestatic

Parameters

base	CADC peripheral base address.

Returns: Mask value for the sample slots if their results exceed the low limit.

static void CADC_ClearSampleLowLimitStatusFlags	(	ADC_Type *	base,
		uint16_t	sampleMask
	)

inlinestatic

Parameters

base	CADC peripheral base address.
sampleMask	Mask value for the sample slots' flags to be cleared.

static uint16_t CADC_GetSampleHighLimitStatusFlags ( ADC_Type * base )

inlinestatic

Parameters

base	CADC peripheral base address.

Returns: Mask value for the sample slots if their results exceed the high limit.

static void CADC_ClearSampleHighLimitStatusFlags	(	ADC_Type *	base,
		uint16_t	sampleMask
	)

inlinestatic

Parameters

base	CADC peripheral base address.
sampleMask	Mask value for the sample slots to be cleared flags.

static uint16_t CADC_GetSampleZeroCrossingStatusFlags ( ADC_Type * base )

inlinestatic

Parameters

base	CADC peripheral base address.

Returns: Mask value for the sample slots if their results cause the zero crossing event.

static void CADC_ClearSampleZeroCrossingStatusFlags	(	ADC_Type *	base,
		uint16_t	sampleMask
	)

inlinestatic

Parameters

base	CADC peripheral base address.
sampleMask	Mask value for the sample slots to be cleared flags.

static uint16_t CADC_GetSampleResultValue	(	ADC_Type *	base,
		uint16_t	sampleIndex
	)

inlinestatic

This function is to get the sample result value. This returned value keeps it original formation just like in hardware result register. It includes the sign bit as the MSB and 3-bit left shifted value.

Parameters

base	CADC peripheral base address.
sampleIndex	Index of sample slot.

Returns: Sample's conversion value.

Overview

Function groups

Initialization and deinitialization

Each converter

Each sample

Typical use case

Triggered parallel

Data Structures

Macros

Enumerations

Driver version

Initialization and deinitialization

Each Converter

Each Sample

Data Structure Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation