ADC: 12-bit Analog to Digital Converter Driver

Overview

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

Typical use case

Interrupt Configuration

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

Polling Configuration

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

Data Structures
struct	_adc_config
	ADC converter configuration. More...
struct	_adc_hardware_compare_config
	ADC hardware comparison configuration. More...
struct	_adc_fifo_config
	ADC FIFO configuration. More...
struct	_adc_channel_config
	ADC channel conversion configuration. More...

Macros
#define	FSL_ADC_DRIVER_VERSION   (MAKE_VERSION(2, 1, 0))
	ADC driver version. More...

Typedefs
typedef enum _adc_reference_voltage_source	adc_reference_voltage_source_t
	Reference voltage source.
typedef enum _adc_clock_divider	adc_clock_divider_t
	Clock divider for the converter.
typedef enum _adc_resolution_mode	adc_resolution_mode_t
	ADC converter resolution mode.
typedef enum _adc_clock_source	adc_clock_source_t
	ADC input Clock source.
typedef enum _adc_compare_mode	adc_compare_mode_t
	Compare function mode.
typedef struct _adc_config	adc_config_t
	ADC converter configuration.
typedef struct _adc_hardware_compare_config	adc_hardware_compare_config_t
	ADC hardware comparison configuration.
typedef struct _adc_fifo_config	adc_fifo_config_t
	ADC FIFO configuration.
typedef struct _adc_channel_config	adc_channel_config_t
	ADC channel conversion configuration.

Enumerations
enum	_adc_reference_voltage_source {   kADC_ReferenceVoltageSourceAlt0 = 0U,   kADC_ReferenceVoltageSourceAlt1 = 1U }
	Reference voltage source. More...
enum	_adc_clock_divider {   kADC_ClockDivider1 = 0U,   kADC_ClockDivider2 = 1U,   kADC_ClockDivider4 = 2U,   kADC_ClockDivider8 = 3U }
	Clock divider for the converter. More...
enum	_adc_resolution_mode {   kADC_Resolution8BitMode = 0U,   kADC_Resolution10BitMode = 1U,   kADC_Resolution12BitMode = 2U }
	ADC converter resolution mode. More...
enum	_adc_clock_source {   kADC_ClockSourceAlt0 = 0U,   kADC_ClockSourceAlt1 = 1U,   kADC_ClockSourceAlt2 = 2U,   kADC_ClockSourceAlt3 = 3U }
	ADC input Clock source. More...
enum	_adc_compare_mode {   kADC_CompareDisableMode = 0U,   kADC_CompareLessMode = 2U,   kADC_CompareGreaterOrEqualMode = 3U }
	Compare function mode. More...
enum	_adc_status_flags {   kADC_ActiveFlag = ADC_SC2_ADACT_MASK,   kADC_FifoEmptyFlag = ADC_SC2_FEMPTY_MASK,   kADC_FifoFullFlag = ADC_SC2_FFULL_MASK }
	ADC status flags mask. More...

Initialization
void	ADC_Init (ADC_Type *base, const adc_config_t *config)
	Initializes the ADC module. More...
void	ADC_Deinit (ADC_Type *base)
	De-initialize the ADC module. More...
void	ADC_GetDefaultConfig (adc_config_t *config)
	Gets an available pre-defined settings for the converter's configuration. More...
static void	ADC_EnableHardwareTrigger (ADC_Type *base, bool enable)
	Enable the hardware trigger mode. More...
void	ADC_SetHardwareCompare (ADC_Type *base, const adc_hardware_compare_config_t *config)
	Configure the hardware compare mode. More...
void	ADC_SetFifoConfig (ADC_Type *base, const adc_fifo_config_t *config)
	Configure the Fifo mode. More...
void	ADC_GetDefaultFIFOConfig (adc_fifo_config_t *config)
	Gets an available pre-defined settings for the FIFO's configuration. More...
void	ADC_SetChannelConfig (ADC_Type *base, const adc_channel_config_t *config)
	Configures the conversion channel. More...
bool	ADC_GetChannelStatusFlags (ADC_Type *base)
	Get the status flags of channel. More...
uint32_t	ADC_GetStatusFlags (ADC_Type *base)
	Get the ADC status flags. More...
static void	ADC_EnableAnalogInput (ADC_Type *base, uint32_t mask, bool enable)
	Disables the I/O port control of the pins used as analog inputs. More...
static uint32_t	ADC_GetChannelConversionValue (ADC_Type *base)
	Gets the conversion value. More...

---

Data Structure Documentation

struct _adc_config

Data Fields
adc_reference_voltage_source_t	referenceVoltageSource
	Selects the voltage reference source used for conversions. More...
bool	enableLowPower
	Enable low power mode. More...
bool	enableLongSampleTime
	Enable long sample time mode. More...
adc_clock_divider_t	clockDivider
	Select the divider of input clock source. More...
adc_resolution_mode_t	ResolutionMode
	Select the sample resolution mode. More...
adc_clock_source_t	clockSource
	Select the input Clock source. More...

Field Documentation

adc_reference_voltage_source_t _adc_config::referenceVoltageSource

>

bool _adc_config::enableLowPower

The power is reduced at the expense of maximum clock speed. >

bool _adc_config::enableLongSampleTime

>

adc_clock_divider_t _adc_config::clockDivider

>

adc_resolution_mode_t _adc_config::ResolutionMode

>

adc_clock_source_t _adc_config::clockSource

>

struct _adc_hardware_compare_config

Data Fields
uint32_t	compareValue
	Setting the compare value. More...
adc_compare_mode_t	compareMode
	Setting the compare mode. More...

Field Documentation

uint32_t _adc_hardware_compare_config::compareValue

The value are compared to the conversion result. >

adc_compare_mode_t _adc_hardware_compare_config::compareMode

Refer to "adc_compare_mode_t". >

struct _adc_fifo_config

Data Fields
bool	enableFifoScanMode
	The field is valid when FIFO is enabled. More...
bool	enableCompareAndMode
	The field is valid when FIFO is enabled. More...
uint32_t	FifoDepth
	Setting the depth of FIFO. More...

Field Documentation

bool _adc_fifo_config::enableFifoScanMode

Enable the FIFO scan mode. If enable, ADC will repeat using the first FIFO channel as the conversion channel until the result FIFO is fulfilled. >

bool _adc_fifo_config::enableCompareAndMode

If enable, ADC will AND all of compare triggers and set COCO after all of compare triggers occur. If disable, ADC will OR all of compare triggers and set COCO after at least one of compare trigger occurs. >

uint32_t _adc_fifo_config::FifoDepth

Depth of fifo is FifoDepth + 1. When FifoDepth = 0U, the FIFO is DISABLED. When FifoDepth is set to nonzero, the FIFO function is ENABLED and the depth is indicated by the FifoDepth field. >

struct _adc_channel_config

Data Fields
uint32_t	channelNumber
	Setting the conversion channel number. More...
bool	enableContinuousConversion
	enables continuous conversions. More...
bool	enableInterruptOnConversionCompleted
	Generate an interrupt request once the conversion is completed. More...

Field Documentation

uint32_t _adc_channel_config::channelNumber

The available range is 0-31. See channel connection information for each chip in Reference Manual document.

bool _adc_channel_config::enableContinuousConversion

>

bool _adc_channel_config::enableInterruptOnConversionCompleted

Macro Definition Documentation

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

Version 2.1.0.

Enumeration Type Documentation

enum _adc_reference_voltage_source

Enumerator
kADC_ReferenceVoltageSourceAlt0	Default voltage reference pin pair (VREFH/VREFL). >
kADC_ReferenceVoltageSourceAlt1	Analog supply pin pair (VDDA/VSSA). >

enum _adc_clock_divider

Enumerator
kADC_ClockDivider1	Divide ration = 1, and clock rate = Input clock. >
kADC_ClockDivider2	Divide ration = 2, and clock rate = Input clock / 2. >
kADC_ClockDivider4	Divide ration = 3, and clock rate = Input clock / 4. >
kADC_ClockDivider8	Divide ration = 4, and clock rate = Input clock / 8. >

enum _adc_resolution_mode

Enumerator
kADC_Resolution8BitMode	8-bit conversion (N = 8). >
kADC_Resolution10BitMode	10-bit conversion (N = 10) >
kADC_Resolution12BitMode	12-bit conversion (N = 12) >

enum _adc_clock_source

Enumerator
kADC_ClockSourceAlt0	Bus clock. >
kADC_ClockSourceAlt1	Bus clock divided by 2. >
kADC_ClockSourceAlt2	Alternate clock (ALTCLK). >
kADC_ClockSourceAlt3	Asynchronous clock (ADACK). >

enum _adc_compare_mode

Enumerator
kADC_CompareDisableMode	Compare function disabled. >
kADC_CompareLessMode	Compare triggers when input is less than compare level. >
kADC_CompareGreaterOrEqualMode	Compare triggers when input is greater than or equal to compare level. >

enum _adc_status_flags

Enumerator
kADC_ActiveFlag	Indicates that a conversion is in progress. >
kADC_FifoEmptyFlag	Indicates that ADC result FIFO have no valid new data. >
kADC_FifoFullFlag	Indicates that ADC result FIFO is full. >

Function Documentation

void ADC_Init	(	ADC_Type *	base,
		const adc_config_t *	config
	)

Parameters

base	ADC peripheral base address.
config	Pointer to configuration structure. See "adc_config_t".

void ADC_Deinit

(

ADC_Type *

base

)

Parameters

base	ADC peripheral base address.

void ADC_GetDefaultConfig

(

adc_config_t *

config

)

This function initializes the converter configuration structure with available settings. The default values are as follows.

*   config->referenceVoltageSource = kADC_ReferenceVoltageSourceAlt0;
*   config->enableLowPower = false;
*   config->enableLongSampleTime = false;
*   config->clockDivider = kADC_ClockDivider1;
*   config->ResolutionMode = kADC_Resolution8BitMode;
*   config->clockSource = kADC_ClockSourceAlt0;
* 

Parameters

config

Pointer to the configuration structure.

static void ADC_EnableHardwareTrigger ( ADC_Type *  base, bool  enable  )

inlinestatic

Parameters

base	ADC peripheral base address.
enable	Switcher of the hardware trigger feature. "true" means enabled, "false" means not enabled.

void ADC_SetHardwareCompare	(	ADC_Type *	base,
		const adc_hardware_compare_config_t *	config
	)

The compare function can be configured to check for an upper or lower limit. After the input is sampled and converted, the result is added to the complement of the compare value (ADC_CV).

Parameters

base	ADC peripheral base address.
config	Pointer to "adc_hardware_compare_config_t" structure.

void ADC_SetFifoConfig	(	ADC_Type *	base,
		const adc_fifo_config_t *	config
	)

The ADC module supports FIFO operation to minimize the interrupts to CPU in order to reduce CPU loading in ADC interrupt service routines. This module contains two FIFOs to buffer analog input channels and analog results respectively.

Parameters

base	ADC peripheral base address.
config	Pointer to "adc_fifo_config_t" structure.

void ADC_GetDefaultFIFOConfig

(

adc_fifo_config_t *

config

)

Parameters

config

Pointer to the FIFO configuration structure, please refer to adc_fifo_config_t for details.

void ADC_SetChannelConfig	(	ADC_Type *	base,
		const adc_channel_config_t *	config
	)

This operation triggers the conversion when in software trigger mode. When in hardware trigger mode, this API configures the channel while the external trigger source helps to trigger the conversion.

Parameters

base	ADC peripheral base address.
config	Pointer to "adc_channel_config_t" structure.

bool ADC_GetChannelStatusFlags

(

ADC_Type *

base

)

Parameters

base	ADC peripheral base address.

Returns

"True" means conversion has completed and "false" means conversion has not completed.

uint32_t ADC_GetStatusFlags

(

ADC_Type *

base

)

Parameters

base	ADC peripheral base address.

Returns

Flags' mask if indicated flags are asserted. See "_adc_status_flags".

static void ADC_EnableAnalogInput ( ADC_Type *  base, uint32_t  mask, bool  enable  )

inlinestatic

When a pin control register bit is set, the following conditions are forced for the associated MCU pin: -The output buffer is forced to its high impedance state. -The input buffer is disabled. A read of the I/O port returns a zero for any pin with its input buffer disabled. -The pullup is disabled.

Parameters

base	ADC peripheral base address.
mask	The mask of the pin associated with channel ADx. Valid range is AD0:0x1U ~ AD15:0x8000U. For example: If enable AD0, AD1 and AD2 pins, mask should be set to 0x7U.
enable	The "true" means enabled, "false" means not enabled.

static uint32_t ADC_GetChannelConversionValue ( ADC_Type *  base )

inlinestatic

Parameters

base	ADC peripheral base address.

Returns

Conversion value.