Overview

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

The DAC driver includes a basic DAC module (converter) and a DAC buffer.

The basic DAC module supports operations unique to the DAC converter in each DAC instance. The APIs in this section are used in the initialization phase, which enables the DAC module in the application. The APIs enable/disable the clock, enable/disable the module, and configure the converter. Call the initial APIs to prepare the DAC module for the application.

The DAC buffer operates the DAC hardware buffer. The DAC module supports a hardware buffer to keep a group of DAC values to be converted. This feature supports updating the DAC output value automatically by triggering the buffer read pointer to move in the buffer. Use the APIs to configure the hardware buffer's trigger mode, watermark, work mode, and use size. Additionally, the APIs operate the DMA, interrupts, flags, the pointer (the index of the buffer), item values, and so on.

Note that the most functional features are designed for the DAC hardware buffer.

Typical use case

Working as a basic DAC without the hardware buffer feature

// ...
// Configures the DAC.
DAC_GetDefaultConfig(&dacConfigStruct);
DAC_Init(DEMO_DAC_INSTANCE, &dacConfigStruct);
DAC_Enable(DEMO_DAC_INSTANCE, true);
DAC_SetBufferReadPointer(DEMO_DAC_INSTANCE, 0U);
// ...
DAC_SetBufferValue(DEMO_DAC_INSTANCE, 0U, dacValue);

Working with the hardware buffer

    // ...
    EnableIRQ(DEMO_DAC_IRQ_ID);
    // ...
    // Configures the DAC.
    DAC_GetDefaultConfig(&dacConfigStruct);
    DAC_Init(DEMO_DAC_INSTANCE, &dacConfigStruct);
    DAC_Enable(DEMO_DAC_INSTANCE, true);
    // Configures the DAC buffer.
    DAC_GetDefaultBufferConfig(&dacBufferConfigStruct);
    DAC_SetBufferConfig(DEMO_DAC_INSTANCE, &dacBufferConfigStruct);
    DAC_SetBufferReadPointer(DEMO_DAC_INSTANCE, 0U); // Make sure the read pointer to the start.
    for (index = 0U, dacValue = 0; index < DEMO_DAC_USED_BUFFER_SIZE; index++, dacValue += (0xFFFU / DEMO_DAC_USED_BUFFER_SIZE))
    {
        DAC_SetBufferValue(DEMO_DAC_INSTANCE, index, dacValue);
    }
    // Clears flags.
#if defined(FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION) && FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION
    g_DacBufferWatermarkInterruptFlag = false;
#endif // FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION
    g_DacBufferReadPointerTopPositionInterruptFlag = false;
    g_DacBufferReadPointerBottomPositionInterruptFlag = false;
    // Enables interrupts.
    mask = 0U;
#if defined(FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION) && FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION
    mask |= kDAC_BufferWatermarkInterruptEnable;
#endif // FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION
    mask |= kDAC_BufferReadPointerTopInterruptEnable | kDAC_BufferReadPointerBottomInterruptEnable;
    DAC_EnableBuffer(DEMO_DAC_INSTANCE, true);
    DAC_EnableBufferInterrupts(DEMO_DAC_INSTANCE, mask);
// ISR for the DAC interrupt.
void DEMO_DAC_IRQ_HANDLER_FUNC(void)
{
    uint32_t flags = DAC_GetBufferStatusFlags(DEMO_DAC_INSTANCE);
#if defined(FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION) && FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION
    if (kDAC_BufferWatermarkFlag == (kDAC_BufferWatermarkFlag & flags))
    {
        g_DacBufferWatermarkInterruptFlag = true;
    }
#endif // FSL_FEATURE_DAC_HAS_WATERMARK_DETECTION
    if (kDAC_BufferReadPointerTopPositionFlag == (kDAC_BufferReadPointerTopPositionFlag & flags))
    {
        g_DacBufferReadPointerTopPositionInterruptFlag = true;
    }
    if (kDAC_BufferReadPointerBottomPositionFlag == (kDAC_BufferReadPointerBottomPositionFlag & flags))
    {
        g_DacBufferReadPointerBottomPositionInterruptFlag = true;
    }
    DAC_ClearBufferStatusFlags(DEMO_DAC_INSTANCE, flags); /* Clear flags. */
}

Data Structures
struct	dac_config_t
	DAC module configuration. More...

struct	dac_buffer_config_t
	DAC buffer configuration. More...

Enumerations
enum	_dac_buffer_status_flags { kDAC_BufferWatermarkFlag = DAC_SR_DACBFWMF_MASK, kDAC_BufferReadPointerTopPositionFlag = DAC_SR_DACBFRPTF_MASK, kDAC_BufferReadPointerBottomPositionFlag = DAC_SR_DACBFRPBF_MASK }
	DAC buffer flags. More...

enum	_dac_buffer_interrupt_enable { kDAC_BufferWatermarkInterruptEnable = DAC_C0_DACBWIEN_MASK, kDAC_BufferReadPointerTopInterruptEnable = DAC_C0_DACBTIEN_MASK, kDAC_BufferReadPointerBottomInterruptEnable = DAC_C0_DACBBIEN_MASK }
	DAC buffer interrupts. More...

enum	dac_reference_voltage_source_t { kDAC_ReferenceVoltageSourceVref1 = 0U, kDAC_ReferenceVoltageSourceVref2 = 1U }
	DAC reference voltage source. More...

enum	dac_buffer_trigger_mode_t { kDAC_BufferTriggerByHardwareMode = 0U, kDAC_BufferTriggerBySoftwareMode = 1U }
	DAC buffer trigger mode. More...

enum	dac_buffer_watermark_t { kDAC_BufferWatermark1Word = 0U, kDAC_BufferWatermark2Word = 1U, kDAC_BufferWatermark3Word = 2U, kDAC_BufferWatermark4Word = 3U }
	DAC buffer watermark. More...

enum	dac_buffer_work_mode_t { kDAC_BufferWorkAsNormalMode = 0U, kDAC_BufferWorkAsOneTimeScanMode }
	DAC buffer work mode. More...

Driver version
#define	FSL_DAC_DRIVER_VERSION (MAKE_VERSION(2, 0, 1))
	DAC driver version 2.0.1. More...

Initialization
void	DAC_Init (DAC_Type base, const dac_config_t config)
	Initializes the DAC module. More...

void	DAC_Deinit (DAC_Type *base)
	De-initializes the DAC module. More...

void	DAC_GetDefaultConfig (dac_config_t *config)
	Initializes the DAC user configuration structure. More...

static void	DAC_Enable (DAC_Type *base, bool enable)
	Enables the DAC module. More...

Buffer
static void	DAC_EnableBuffer (DAC_Type *base, bool enable)
	Enables the DAC buffer. More...

void	DAC_SetBufferConfig (DAC_Type base, const dac_buffer_config_t config)
	Configures the CMP buffer. More...

void	DAC_GetDefaultBufferConfig (dac_buffer_config_t *config)
	Initializes the DAC buffer configuration structure. More...

static void	DAC_EnableBufferDMA (DAC_Type *base, bool enable)
	Enables the DMA for DAC buffer. More...

void	DAC_SetBufferValue (DAC_Type *base, uint8_t index, uint16_t value)
	Sets the value for items in the buffer. More...

static void	DAC_DoSoftwareTriggerBuffer (DAC_Type *base)
	Triggers the buffer using software and updates the read pointer of the DAC buffer. More...

static uint8_t	DAC_GetBufferReadPointer (DAC_Type *base)
	Gets the current read pointer of the DAC buffer. More...

void	DAC_SetBufferReadPointer (DAC_Type *base, uint8_t index)
	Sets the current read pointer of the DAC buffer. More...

void	DAC_EnableBufferInterrupts (DAC_Type *base, uint32_t mask)
	Enables interrupts for the DAC buffer. More...

void	DAC_DisableBufferInterrupts (DAC_Type *base, uint32_t mask)
	Disables interrupts for the DAC buffer. More...

uint32_t	DAC_GetBufferStatusFlags (DAC_Type *base)
	Gets the flags of events for the DAC buffer. More...

void	DAC_ClearBufferStatusFlags (DAC_Type *base, uint32_t mask)
	Clears the flags of events for the DAC buffer. More...

Data Structure Documentation

struct dac_config_t

Data Fields
dac_reference_voltage_source_t	referenceVoltageSource
	Select the DAC reference voltage source. More...

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

Field Documentation

dac_reference_voltage_source_t dac_config_t::referenceVoltageSource

bool dac_config_t::enableLowPowerMode

struct dac_buffer_config_t

Data Fields
dac_buffer_trigger_mode_t	triggerMode
	Select the buffer's trigger mode. More...

dac_buffer_watermark_t	watermark
	Select the buffer's watermark. More...

dac_buffer_work_mode_t	workMode
	Select the buffer's work mode. More...

uint8_t	upperLimit
	Set the upper limit for the buffer index. More...

Field Documentation

dac_buffer_trigger_mode_t dac_buffer_config_t::triggerMode

dac_buffer_watermark_t dac_buffer_config_t::watermark

dac_buffer_work_mode_t dac_buffer_config_t::workMode

uint8_t dac_buffer_config_t::upperLimit

Normally, 0-15 is available for a buffer with 16 items.

Macro Definition Documentation

#define FSL_DAC_DRIVER_VERSION (MAKE_VERSION(2, 0, 1))

Enumeration Type Documentation

enum _dac_buffer_status_flags

Enumerator
kDAC_BufferWatermarkFlag	DAC Buffer Watermark Flag.
kDAC_BufferReadPointerTopPositionFlag	DAC Buffer Read Pointer Top Position Flag.
kDAC_BufferReadPointerBottomPositionFlag	DAC Buffer Read Pointer Bottom Position Flag.

enum _dac_buffer_interrupt_enable

Enumerator
kDAC_BufferWatermarkInterruptEnable	DAC Buffer Watermark Interrupt Enable.
kDAC_BufferReadPointerTopInterruptEnable	DAC Buffer Read Pointer Top Flag Interrupt Enable.
kDAC_BufferReadPointerBottomInterruptEnable	DAC Buffer Read Pointer Bottom Flag Interrupt Enable.

enum dac_reference_voltage_source_t

Enumerator
kDAC_ReferenceVoltageSourceVref1	The DAC selects DACREF_1 as the reference voltage.
kDAC_ReferenceVoltageSourceVref2	The DAC selects DACREF_2 as the reference voltage.

enum dac_buffer_trigger_mode_t

Enumerator
kDAC_BufferTriggerByHardwareMode	The DAC hardware trigger is selected.
kDAC_BufferTriggerBySoftwareMode	The DAC software trigger is selected.

enum dac_buffer_watermark_t

Enumerator
kDAC_BufferWatermark1Word	1 word away from the upper limit.
kDAC_BufferWatermark2Word	2 words away from the upper limit.
kDAC_BufferWatermark3Word	3 words away from the upper limit.
kDAC_BufferWatermark4Word	4 words away from the upper limit.

enum dac_buffer_work_mode_t

Enumerator
kDAC_BufferWorkAsNormalMode	Normal mode.
kDAC_BufferWorkAsOneTimeScanMode	One-Time Scan mode.

Function Documentation

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

This function initializes the DAC module including the following operations.

Enabling the clock for DAC module.
Configuring the DAC converter with a user configuration.
Enabling the DAC module.

Parameters

base	DAC peripheral base address.
config	Pointer to the configuration structure. See "dac_config_t".

void DAC_Deinit ( DAC_Type * base )

This function de-initializes the DAC module including the following operations.

Disabling the DAC module.
Disabling the clock for the DAC module.

Parameters

base	DAC peripheral base address.

void DAC_GetDefaultConfig ( dac_config_t * config )

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

*   config->referenceVoltageSource = kDAC_ReferenceVoltageSourceVref2;
*   config->enableLowPowerMode = false;
* 

Parameters

config Pointer to the configuration structure. See "dac_config_t".

static void DAC_Enable	(	DAC_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	DAC peripheral base address.
enable	Enables or disables the feature.

static void DAC_EnableBuffer	(	DAC_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	DAC peripheral base address.
enable	Enables or disables the feature.

void DAC_SetBufferConfig	(	DAC_Type *	base,
		const dac_buffer_config_t *	config
	)

Parameters

base	DAC peripheral base address.
config	Pointer to the configuration structure. See "dac_buffer_config_t".

void DAC_GetDefaultBufferConfig ( dac_buffer_config_t * config )

This function initializes the DAC buffer configuration structure to default values. The default values are as follows.

*   config->triggerMode = kDAC_BufferTriggerBySoftwareMode;
*   config->watermark   = kDAC_BufferWatermark1Word;
*   config->workMode    = kDAC_BufferWorkAsNormalMode;
*   config->upperLimit  = DAC_DATL_COUNT - 1U;
* 

Parameters

config Pointer to the configuration structure. See "dac_buffer_config_t".

static void DAC_EnableBufferDMA	(	DAC_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	DAC peripheral base address.
enable	Enables or disables the feature.

void DAC_SetBufferValue	(	DAC_Type *	base,
		uint8_t	index,
		uint16_t	value
	)

Parameters

base	DAC peripheral base address.
index	Setting the index for items in the buffer. The available index should not exceed the size of the DAC buffer.
value	Setting the value for items in the buffer. 12-bits are available.

static void DAC_DoSoftwareTriggerBuffer ( DAC_Type * base )

inlinestatic

This function triggers the function using software. The read pointer of the DAC buffer is updated with one step after this function is called. Changing the read pointer depends on the buffer's work mode.

Parameters

base	DAC peripheral base address.

static uint8_t DAC_GetBufferReadPointer ( DAC_Type * base )

inlinestatic

This function gets the current read pointer of the DAC buffer. The current output value depends on the item indexed by the read pointer. It is updated either by a software trigger or a hardware trigger.

Parameters

base	DAC peripheral base address.

Returns: The current read pointer of the DAC buffer.

void DAC_SetBufferReadPointer	(	DAC_Type *	base,
		uint8_t	index
	)

This function sets the current read pointer of the DAC buffer. The current output value depends on the item indexed by the read pointer. It is updated either by a software trigger or a hardware trigger. After the read pointer changes, the DAC output value also changes.

Parameters

base	DAC peripheral base address.
index	Setting an index value for the pointer.

void DAC_EnableBufferInterrupts	(	DAC_Type *	base,
		uint32_t	mask
	)

Parameters

base	DAC peripheral base address.
mask	Mask value for interrupts. See "_dac_buffer_interrupt_enable".

void DAC_DisableBufferInterrupts	(	DAC_Type *	base,
		uint32_t	mask
	)

Parameters

base	DAC peripheral base address.
mask	Mask value for interrupts. See "_dac_buffer_interrupt_enable".

uint32_t DAC_GetBufferStatusFlags ( DAC_Type * base )

Parameters

base	DAC peripheral base address.

Returns: Mask value for the asserted flags. See "_dac_buffer_status_flags".

void DAC_ClearBufferStatusFlags	(	DAC_Type *	base,
		uint32_t	mask
	)

Parameters

base	DAC peripheral base address.
mask	Mask value for flags. See "_dac_buffer_status_flags_t".

Overview

Typical use case

Working as a basic DAC without the hardware buffer feature

Working with the hardware buffer

Data Structures

Enumerations

Driver version

Initialization

Buffer

Data Structure Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation