Overview

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

This DAC is the 12-bit resolution digital-to-analog converters with a programmable reference generator output. Its output data items are loaded into a FIFO, so that various FIFO modes can be used to output the value for user-defined sequence.

The DAC driver provides a user-friendly interface to operate the DAC peripheral. The user can initialize/deinitialize the DAC driver, set data into FIFO, or enable the interrupt DMA for special events so that the hardware can process the DAC output data automatically. Also, the configuration for the software and hardware trigger are also included in the driver.

Typical use case

A simple use case to output the user-defined DAC value.

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

Working with the trigger

Once more than one data is filled into the FIFO, the output pointer would move in configured mode when a trigger come. This trigger can be from software or hardware, and move one item for each trigger. Also, the interrupt/DMA event could be activated when the output pointer hits to the configured position.

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

Files
file	fsl_dac.h

Data Structures
struct	_dac_config
	DAC configuration structure. More...

Typedefs
typedef enum _dac_fifo_trigger_mode	dac_fifo_trigger_mode_t
	DAC FIFO trigger mode.

typedef enum _dac_fifo_work_mode	dac_fifo_work_mode_t
	DAC FIFO work mode.

typedef enum _dac_reference_voltage_source	dac_reference_voltage_source_t
	DAC reference voltage source.

typedef struct _dac_config	dac_config_t
	DAC configuration structure.

Enumerations
enum	{ kDAC_ResetFIFO = LPDAC_RCR_FIFORST_MASK, kDAC_ResetLogic = LPDAC_RCR_SWRST_MASK }
	DAC reset control. More...

enum	{ kDAC_FIFOFullInterruptEnable = LPDAC_IER_FULL_IE_MASK, kDAC_FIFOEmptyInterruptEnable = LPDAC_IER_EMPTY_IE_MASK, kDAC_FIFOWatermarkInterruptEnable = LPDAC_IER_WM_IE_MASK, kDAC_SwingBackInterruptEnable = LPDAC_IER_SWBK_IE_MASK, kDAC_FIFOOverflowInterruptEnable = LPDAC_IER_OF_IE_MASK, kDAC_FIFOUnderflowInterruptEnable = LPDAC_IER_UF_IE_MASK }
	DAC interrupts. More...

enum	{ kDAC_FIFOEmptyDMAEnable = LPDAC_DER_EMPTY_DMAEN_MASK, kDAC_FIFOWatermarkDMAEnable = LPDAC_DER_WM_DMAEN_MASK }
	DAC DMA switchers. More...

enum	{ kDAC_FIFOUnderflowFlag = LPDAC_FSR_UF_MASK, kDAC_FIFOOverflowFlag, kDAC_FIFOSwingBackFlag = LPDAC_FSR_SWBK_MASK, kDAC_FIFOWatermarkFlag = LPDAC_FSR_WM_MASK, kDAC_FIFOEmptyFlag = LPDAC_FSR_EMPTY_MASK, kDAC_FIFOFullFlag = LPDAC_FSR_FULL_MASK }
	DAC status flags. More...

enum	_dac_fifo_trigger_mode { kDAC_FIFOTriggerByHardwareMode = 0U, kDAC_FIFOTriggerBySoftwareMode = 1U }
	DAC FIFO trigger mode. More...

enum	_dac_fifo_work_mode { kDAC_FIFODisabled = 0U, kDAC_FIFOWorkAsNormalMode = 1U, kDAC_FIFOWorkAsSwingMode = 2U }
	DAC FIFO work mode. More...

enum	_dac_reference_voltage_source { kDAC_ReferenceVoltageSourceAlt1 = 0U, kDAC_ReferenceVoltageSourceAlt2 = 1U }
	DAC reference voltage source. More...

Driver version
#define	FSL_DAC_DRIVER_VERSION (MAKE_VERSION(2, 1, 2))
	DAC driver version 2.1.2. More...

Initialization and de-initialization
void	DAC_Init (LPDAC_Type base, const dac_config_t config)
	Initialize the DAC module with common configuartion. More...

void	DAC_GetDefaultConfig (dac_config_t *config)
	Get the default settings for initialization's configuration. More...

void	DAC_Deinit (LPDAC_Type *base)
	De-initialize the DAC module. More...

static void	DAC_SetReset (LPDAC_Type *base, uint32_t mask)
	Assert the reset control to part hardware. More...

static void	DAC_ClearReset (LPDAC_Type *base, uint32_t mask)
	Clear the reset control to part hardware. More...

static void	DAC_Enable (LPDAC_Type *base, bool enable)
	Enable the DAC hardware system or not. More...

Interrupts
static void	DAC_EnableInterrupts (LPDAC_Type *base, uint32_t mask)
	Enable the interrupts. More...

static void	DAC_DisableInterrupts (LPDAC_Type *base, uint32_t mask)
	Disable the interrupts. More...

DMA control
static void	DAC_EnableDMA (LPDAC_Type *base, uint32_t mask, bool enable)
	Enable the DMA switchers or not. More...

Status flags
static uint32_t	DAC_GetStatusFlags (LPDAC_Type *base)
	Get status flags of DAC module. More...

static void	DAC_ClearStatusFlags (LPDAC_Type *base, uint32_t flags)
	Clear status flags of DAC module. More...

Functional feature
static void	DAC_SetData (LPDAC_Type *base, uint32_t value)
	Set data into the entry of FIFO buffer. More...

static uint32_t	DAC_GetFIFOWritePointer (LPDAC_Type *base)
	Get the value of the FIFO write pointer. More...

static uint32_t	DAC_GetFIFOReadPointer (LPDAC_Type *base)
	Get the value of the FIFO read pointer. More...

static void	DAC_DoSoftwareTriggerFIFO (LPDAC_Type *base)
	Do software trigger to FIFO when in software mode. More...

Data Structure Documentation

struct _dac_config

Data Fields
uint32_t	fifoWatermarkLevel
	FIFO's watermark, the max value can be the hardware FIFO size. More...

dac_fifo_trigger_mode_t	fifoTriggerMode
	Select the trigger mode for FIFO. More...

dac_fifo_work_mode_t	fifoWorkMode
	Select the work mode for FIFO. More...

bool	enableLowPowerMode
	Enable the low power mode. More...

dac_reference_voltage_source_t	referenceVoltageSource
	Select the reference voltage source. More...

Field Documentation

uint32_t _dac_config::fifoWatermarkLevel

dac_fifo_trigger_mode_t _dac_config::fifoTriggerMode

dac_fifo_work_mode_t _dac_config::fifoWorkMode

bool _dac_config::enableLowPowerMode

dac_reference_voltage_source_t _dac_config::referenceVoltageSource

Macro Definition Documentation

#define FSL_DAC_DRIVER_VERSION (MAKE_VERSION(2, 1, 2))

Enumeration Type Documentation

anonymous enum

Enumerator
kDAC_ResetFIFO	Resets the FIFO pointers and flags.
kDAC_ResetLogic	Resets all DAC registers and internal logic.

anonymous enum

Enumerator
kDAC_FIFOFullInterruptEnable	FIFO full interrupt enable.
kDAC_FIFOEmptyInterruptEnable	FIFO empty interrupt enable.
kDAC_FIFOWatermarkInterruptEnable	FIFO watermark interrupt enable.
kDAC_SwingBackInterruptEnable	Swing back one cycle complete interrupt enable.
kDAC_FIFOOverflowInterruptEnable	FIFO overflow interrupt enable.
kDAC_FIFOUnderflowInterruptEnable	FIFO underflow interrupt enable.

anonymous enum

Enumerator
kDAC_FIFOEmptyDMAEnable	FIFO empty DMA enable.
kDAC_FIFOWatermarkDMAEnable	FIFO watermark DMA enable.

anonymous enum

Enumerator
kDAC_FIFOUnderflowFlag	This flag means that there is a new trigger after the buffer is empty. The FIFO read pointer will not increase in this case and the data sent to DAC analog conversion will not changed. This flag is cleared by writing a 1 to it.
kDAC_FIFOOverflowFlag	This flag indicates that data is intended to write into FIFO after the buffer is full. The writer pointer will not increase in this case. The extra data will not be written into the FIFO. This flag is cleared by writing a 1 to it.
kDAC_FIFOSwingBackFlag	This flag indicates that the DAC has completed one period of conversion in swing back mode. It means that the read pointer has increased to the top (write pointer) once and then decreased to zero once. For example, after three data is written to FIFO, the writer pointer is now 3. Then, if continually triggered, the read pointer will swing like: 0-1-2-1-0-1-2-, and so on. After the fourth trigger, the flag is set. This flag is cleared by writing a 1 to it.
kDAC_FIFOWatermarkFlag	This field is set if the remaining data in FIFO is less than or equal to the setting value of wartermark. By writing data into FIFO by DMA or CPU, this flag is cleared automatically when the data in FIFO is more than the setting value of watermark.
kDAC_FIFOEmptyFlag	FIFO empty flag.
kDAC_FIFOFullFlag	FIFO full flag.

enum _dac_fifo_trigger_mode

Enumerator
kDAC_FIFOTriggerByHardwareMode	Buffer would be triggered by hardware.
kDAC_FIFOTriggerBySoftwareMode	Buffer would be triggered by software.

enum _dac_fifo_work_mode

Enumerator

kDAC_FIFODisabled

FIFO mode is disabled and buffer mode is enabled.

Any data written to DATA[DATA] goes to buffer then goes to conversion.

kDAC_FIFOWorkAsNormalMode

FIFO mode is enabled.

Data will be first read from FIFO to buffer then goes to conversion.

kDAC_FIFOWorkAsSwingMode

In swing mode, the read pointer swings between the writer pointer and zero.

That is, the trigger increases the read pointer till reach the writer pointer and decreases the read pointer till zero, and so on. The FIFO empty/full/watermark flag will not update during swing back mode.

enum _dac_reference_voltage_source

Enumerator
kDAC_ReferenceVoltageSourceAlt1	The DAC selects VREFH_INT as the reference voltage.
kDAC_ReferenceVoltageSourceAlt2	The DAC selects VREFH_EXT as the reference voltage.

Function Documentation

void DAC_Init	(	LPDAC_Type *	base,
		const dac_config_t *	config
	)

The clock will be enabled in this function.

Parameters

base	DAC peripheral base address.
config	Pointer to configuration structure.

void DAC_GetDefaultConfig ( dac_config_t * config )

This function initializes the user configuration structure to a default value. The default values are:

*   config->fifoWatermarkLevel = 0U;
*   config->fifoTriggerMode = kDAC_FIFOTriggerByHardwareMode;
*   config->fifoWorkMode = kDAC_FIFODisabled;
*   config->enableLowPowerMode = false;
*   config->referenceVoltageSource = kDAC_ReferenceVoltageSourceAlt1;
* 

Parameters

config Pointer to configuration structure.

void DAC_Deinit ( LPDAC_Type * base )

The clock will be disabled in this function.

Parameters

base	DAC peripheral base address.

static void DAC_SetReset	(	LPDAC_Type *	base,
		uint32_t	mask
	)

inlinestatic

This function is to assert the reset control to part hardware. Responding part hardware would remain reset untill cleared by software.

Parameters

base	DAC peripheral base address.
mask	The reset control mask, see to _dac_reset_control_t.

static void DAC_ClearReset	(	LPDAC_Type *	base,
		uint32_t	mask
	)

inlinestatic

This function is to clear the reset control to part hardware. Responding part hardware would work after the reset control is cleared by software.

Parameters

base	DAC peripheral base address.
mask	The reset control mask, see to _dac_reset_control_t.

static void DAC_Enable	(	LPDAC_Type *	base,
		bool	enable
	)

inlinestatic

This function is to start the Programmable Reference Generator operation or not.

Parameters

base	DAC peripheral base address.
enable	Assertion of indicated event.

static void DAC_EnableInterrupts	(	LPDAC_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	DAC peripheral base address.
mask	Mask value of indicated interrupt events. See to _dac_interrupt_enable.

static void DAC_DisableInterrupts	(	LPDAC_Type *	base,
		uint32_t	mask
	)

inlinestatic

Parameters

base	DAC peripheral base address.
mask	Mask value of indicated interrupt events. See to _dac_interrupt_enable.

static void DAC_EnableDMA	(	LPDAC_Type *	base,
		uint32_t	mask,
		bool	enable
	)

inlinestatic

Parameters

base	DAC peripheral base address.
mask	Mask value of indicated DMA requeset. See to _dac_dma_enable.
enable	Enable the DMA or not.

static uint32_t DAC_GetStatusFlags ( LPDAC_Type * base )

inlinestatic

Parameters

base	DAC peripheral base address.

Returns: Mask value of status flags. See to _dac_status_flags.

static void DAC_ClearStatusFlags	(	LPDAC_Type *	base,
		uint32_t	flags
	)

inlinestatic

Parameters

base	DAC peripheral base address.
flags	Mask value of status flags to be cleared. See to _dac_status_flags.

static void DAC_SetData	(	LPDAC_Type *	base,
		uint32_t	value
	)

inlinestatic

Parameters

base	DAC peripheral base address.
value	Setting value into FIFO buffer.

static uint32_t DAC_GetFIFOWritePointer ( LPDAC_Type * base )

inlinestatic

Parameters

base	DAC peripheral base address.

Returns: Current value of the FIFO write pointer.

static uint32_t DAC_GetFIFOReadPointer ( LPDAC_Type * base )

inlinestatic

Parameters

base	DAC peripheral base address.

Returns: Current value of the FIFO read pointer.

static void DAC_DoSoftwareTriggerFIFO ( LPDAC_Type * base )

inlinestatic

Parameters

base	DAC peripheral base address.

Overview

Typical use case

A simple use case to output the user-defined DAC value.

Working with the trigger

Files

Data Structures

Typedefs

Enumerations

Driver version

Initialization and de-initialization

Interrupts

DMA control

Status flags

Functional feature

Data Structure Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation