Overview

The MCUXpresso SDK provides driver for the Analog Front End (AFE) module of MCUXpresso SDK devices.

The Analog Front End or AFE is an integrated module that is comprised of ΣΔADCs, PGA, filtering and phase compensation blocks. The AFE is responsible for measuring the phase voltage, phase current and neutral current.

Function groups

Channel configuration structures

The driver uses instances of the channel configuration structures to configuration and initialization AFE channel. This structure holds the settings of the AFE measurement channel. The settings include AFE hardware/software triggering, AFE continuous/Single conversion mode, AFE channel mode, AFE channel analog gain, AFE channel oversampling ration. The AFE channel mode selects whether the bypass mode is enabled or disabled and the external clock selection.

User configuration structures

The AFE driver uses instances of the user configuration structure afe_config_t for the AFE driver configuration. This structure holds the configuration which is common for all AFE channels. The settings include AFE low power mode, AFE result format, AFE clock divider mode, AFE clock source mode, and AFE start up delay of modulators.

AFE Initialization

To initialize the AFE driver, for a typical use case, call the AFE_GetDefaultConfig() function which populates the structure. Then, call the AFE_Init() function and pass the base address of the AFE peripheral and a pointer to the user configuration structure.

To configure the AFE channel, for a typical use case call the AFE_GetDefaultChnConfig() function which populates the structure. Then, call the AFE_SetChnConfig() function and pass the base address of the AFE peripheral and a pointer to the channel configuration structure.

AFE Conversion

The driver contains functions for software triggering, a channel delay after trigger setting, a result (raw or converted to right justified), reading and waiting functions.

If the software triggering is enabled (hwTriggerEnable parameter in afe_chn_config_t is a false value), call the AFE_SoftTriggerConv() function to start conversion.

Typical use case

AFE Initialization

/* Get AFE config default */
AFE_GetDefaultConfig(&afeExampleStruct);
afeExampleStruct.startupCount = 80U; /* startupCnt = (Clk_freq/Clk_div)*20e-6 */
/* Get channel config default */
AFE_GetDefaultChannelConfig(&afeChnExampleStruct);
/* Init AFE module */
AFE_Init(AFE, &afeExampleStruct);
/* AFE_Init AFE channel 0 */
AFE_SetChannelConfig(AFE, CHANNEL_INDEX, &afeChnExampleStruct);
/* Disable interrupt */
AFE_DisableChannelInterrupts(AFE, kAFE_Channel0InterruptEnable);
/* Disable DMA */
AFE_EnableChannelDMA(AFE, (uint32_t)kAFE_Channel0DMAEnable, false);

AFE Conversion

/* Software trigger conversion */
while (1)
{
    /* Wait next triger from user */
    PRINTF("Press any key to trigger AFE conversion\r\n");
    GETCHAR();
    /* Software trigger conversion */
    AFE_DoSoftwareTriggerChannel(AFE, kAFE_Channel0Trigger);
    /* Wait until conversion complete */
    while ((kAFE_Channel0ConversionCompleteFlag & AFE_GetChannelStatusFlags(AFE)) == 0)
    {
    }
    /* Read result conversion */
    result0 = (int32_t)AFE_GetChannelConversionValue(AFE, CHANNEL_INDEX);
    /* Print result */
    PRINTF("result0  = %d \r\n", result0);
}

Data Structures
struct	afe_channel_config_t
	Defines the structure to initialize the AFE channel. More...

struct	afe_config_t
	Defines the structure to initialize the AFE module. More...

Enumerations
enum	_afe_channel_status_flag { kAFE_Channel0OverflowFlag = AFE_SR_OVR0_MASK, kAFE_Channel1OverflowFlag = AFE_SR_OVR1_MASK, kAFE_Channel2OverflowFlag = AFE_SR_OVR2_MASK, kAFE_Channel0ReadyFlag = AFE_SR_RDY0_MASK, kAFE_Channel1ReadyFlag = AFE_SR_RDY1_MASK, kAFE_Channel2ReadyFlag = AFE_SR_RDY2_MASK, kAFE_Channel0ConversionCompleteFlag = AFE_SR_COC0_MASK, kAFE_Channel1ConversionCompleteFlag = AFE_SR_COC1_MASK, kAFE_Channel2ConversionCompleteFlag = AFE_SR_COC2_MASK, kAFE_Channel3OverflowFlag = AFE_SR_OVR3_MASK, kAFE_Channel3ReadyFlag = AFE_SR_RDY3_MASK, kAFE_Channel3ConversionCompleteFlag = AFE_SR_COC3_MASK }
	Defines the type of status flags. More...

enum	_afe_channel_interrupt_enable { kAFE_Channel0InterruptEnable = AFE_DI_INTEN0_MASK, kAFE_Channel1InterruptEnable = AFE_DI_INTEN1_MASK, kAFE_Channel2InterruptEnable = AFE_DI_INTEN2_MASK, kAFE_Channel3InterruptEnable = AFE_DI_INTEN3_MASK }
	Defines AFE interrupt enable. More...

enum	_afe_channel_dma_enable { kAFE_Channel0DMAEnable = AFE_DI_DMAEN0_MASK, kAFE_Channel1DMAEnable = AFE_DI_DMAEN1_MASK, kAFE_Channel2DMAEnable = AFE_DI_DMAEN2_MASK, kAFE_Channel3DMAEnable = AFE_DI_DMAEN3_MASK }
	Defines AFE DMA enable. More...

enum	_afe_software_trigger_command { kAFE_Channel0Trigger = AFE_CR_SOFT_TRG0_MASK, kAFE_Channel1Trigger = AFE_CR_SOFT_TRG1_MASK, kAFE_Channel2Trigger = AFE_CR_SOFT_TRG2_MASK, kAFE_Channel3Trigger = AFE_CR_SOFT_TRG3_MASK }
	Defines AFE channel trigger flag. More...

enum	afe_decimator_oversample_ratio_t { kAFE_DecimatorOversampleRatio64 = 0U, kAFE_DecimatorOversampleRatio128 = 1U, kAFE_DecimatorOversampleRatio256 = 2U, kAFE_DecimatorOversampleRatio512 = 3U, kAFE_DecimatorOversampleRatio1024 = 4U, kAFE_DecimatorOversampleRatio2048 = 5U }
	AFE OSR modes. More...

enum	afe_result_format_t { kAFE_ResultFormatLeft = 0U, kAFE_ResultFormatRight = 1U }
	Defines the AFE result format modes. More...

enum	afe_clock_divider_t { kAFE_ClockDivider1 = 0U, kAFE_ClockDivider2 = 1U, kAFE_ClockDivider4 = 2U, kAFE_ClockDivider8 = 3U, kAFE_ClockDivider16 = 4U, kAFE_ClockDivider32 = 5U, kAFE_ClockDivider64 = 6U, kAFE_ClockDivider128 = 7U, kAFE_ClockDivider256 = 8U }
	Defines the AFE clock divider modes. More...

enum	afe_clock_source_t { kAFE_ClockSource0 = 0U, kAFE_ClockSource1 = 1U, kAFE_ClockSource2 = 2U, kAFE_ClockSource3 = 3U }
	Defines the AFE clock source modes. More...

enum	afe_pga_gain_t { kAFE_PgaDisable = 0U, kAFE_PgaGain1 = 1U, kAFE_PgaGain2 = 2U, kAFE_PgaGain4 = 3U, kAFE_PgaGain8 = 4U, kAFE_PgaGain16 = 5U, kAFE_PgaGain32 = 6U }
	Defines the PGA's values. More...

enum	afe_bypass_mode_t { kAFE_BypassInternalClockPositiveEdge = 0U, kAFE_BypassExternalClockPositiveEdge = 1U, kAFE_BypassInternalClockNegativeEdge = 2U, kAFE_BypassExternalClockNegativeEdge = 3U, kAFE_BypassDisable = 4U }
	Defines the bypass modes. More...

Driver version
#define	FSL_AFE_DRIVER_VERSION (MAKE_VERSION(2, 0, 1))
	Version 2.0.1. More...

AFE Initialization
void	AFE_Init (AFE_Type base, const afe_config_t config)
	Initialization for the AFE module. More...

void	AFE_Deinit (AFE_Type *base)
	De-Initialization for the AFE module. More...

void	AFE_GetDefaultConfig (afe_config_t *config)
	Fills the user configure structure. More...

static void	AFE_SoftwareReset (AFE_Type *base, bool enable)
	Software reset the AFE module. More...

static void	AFE_Enable (AFE_Type *base, bool enable)
	Enables all configured AFE channels. More...

AFE Conversion
void	AFE_SetChannelConfig (AFE_Type base, uint32_t channel, const afe_channel_config_t config)
	Configure the selected AFE channel. More...

void	AFE_GetDefaultChannelConfig (afe_channel_config_t *config)
	Fills the channel configuration structure. More...

uint32_t	AFE_GetChannelConversionValue (AFE_Type *base, uint32_t channel)
	Reads the raw conversion value. More...

static void	AFE_DoSoftwareTriggerChannel (AFE_Type *base, uint32_t mask)
	Triggers the AFE conversion by software. More...

static uint32_t	AFE_GetChannelStatusFlags (AFE_Type *base)
	Gets the AFE status flag state. More...

void	AFE_SetChannelPhaseDelayValue (AFE_Type *base, uint32_t channel, uint32_t value)
	Sets phase delays value. More...

static void	AFE_SetChannelPhasetDelayOk (AFE_Type *base)
	Asserts the phase delay setting. More...

static void	AFE_EnableChannelInterrupts (AFE_Type *base, uint32_t mask)
	Enables AFE interrupt. More...

static void	AFE_DisableChannelInterrupts (AFE_Type *base, uint32_t mask)
	Disables AFE interrupt. More...

static uint32_t	AFE_GetEnabledChannelInterrupts (AFE_Type *base)
	Returns mask of all enabled AFE interrupts. More...

void	AFE_EnableChannelDMA (AFE_Type *base, uint32_t mask, bool enable)
	Enables/Disables AFE DMA. More...

Data Structure Documentation

struct afe_channel_config_t

This structure keeps the configuration for the AFE channel.

Data Fields
bool	enableHardwareTrigger
	Enable triggering by hardware. More...

bool	enableContinuousConversion
	Enable continuous conversion mode. More...

afe_bypass_mode_t	channelMode
	Select if channel is in bypassed mode. More...

afe_pga_gain_t	pgaGainSelect
	Select the analog gain applied to the input signal. More...

afe_decimator_oversample_ratio_t	decimatorOversampleRatio
	Select the over sampling ration. More...

Field Documentation

bool afe_channel_config_t::enableHardwareTrigger

bool afe_channel_config_t::enableContinuousConversion

afe_bypass_mode_t afe_channel_config_t::channelMode

afe_pga_gain_t afe_channel_config_t::pgaGainSelect

afe_decimator_oversample_ratio_t afe_channel_config_t::decimatorOversampleRatio

struct afe_config_t

This structure keeps the configuration for the AFE module.

Data Fields
bool	enableLowPower
	Enable low power mode. More...

afe_result_format_t	resultFormat
	Select the result format. More...

afe_clock_divider_t	clockDivider
	Select the clock divider ration for the modulator clock. More...

afe_clock_source_t	clockSource
	Select clock source for modulator clock. More...

uint8_t	startupCount
	Select the start up delay of modulators. More...

Field Documentation

bool afe_config_t::enableLowPower

afe_result_format_t afe_config_t::resultFormat

afe_clock_divider_t afe_config_t::clockDivider

afe_clock_source_t afe_config_t::clockSource

uint8_t afe_config_t::startupCount

Macro Definition Documentation

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

Enumeration Type Documentation

enum _afe_channel_status_flag

Enumerator
kAFE_Channel0OverflowFlag	Channel 0 previous conversion result has not been read and new data has already arrived.
kAFE_Channel1OverflowFlag	Channel 1 previous conversion result has not been read and new data has already arrived.
kAFE_Channel2OverflowFlag	Channel 2 previous conversion result has not been read and new data has already arrived.
kAFE_Channel0ReadyFlag	Channel 0 is ready to conversion.
kAFE_Channel1ReadyFlag	Channel 1 is ready to conversion.
kAFE_Channel2ReadyFlag	Channel 2 is ready to conversion.
kAFE_Channel0ConversionCompleteFlag	Channel 0 conversion is complete.
kAFE_Channel1ConversionCompleteFlag	Channel 1 conversion is complete.
kAFE_Channel2ConversionCompleteFlag	Channel 2 conversion is complete.
kAFE_Channel3OverflowFlag	Channel 3 previous conversion result has not been read and new data has already arrived.
kAFE_Channel3ReadyFlag	Channel 3 is ready to conversion.
kAFE_Channel3ConversionCompleteFlag	Channel 3 conversion is complete.

enum _afe_channel_interrupt_enable

Enumerator
kAFE_Channel0InterruptEnable	Channel 0 Interrupt.
kAFE_Channel1InterruptEnable	Channel 1 Interrupt.
kAFE_Channel2InterruptEnable	Channel 2 Interrupt.
kAFE_Channel3InterruptEnable	Channel 3 Interrupt.

enum _afe_channel_dma_enable

Enumerator
kAFE_Channel0DMAEnable	Channel 0 DMA.
kAFE_Channel1DMAEnable	Channel 1 DMA.
kAFE_Channel2DMAEnable	Channel 2 DMA.
kAFE_Channel3DMAEnable	Channel 3 DMA.

enum _afe_software_trigger_command

Enumerator
kAFE_Channel0Trigger	Channel 0 software trigger.
kAFE_Channel1Trigger	Channel 1 software trigger.
kAFE_Channel2Trigger	Channel 2 software trigger.
kAFE_Channel3Trigger	Channel 3 software trigger.

enum afe_decimator_oversample_ratio_t

Enumerator
kAFE_DecimatorOversampleRatio64	Decimator over sample ratio is 64.
kAFE_DecimatorOversampleRatio128	Decimator over sample ratio is 128.
kAFE_DecimatorOversampleRatio256	Decimator over sample ratio is 256.
kAFE_DecimatorOversampleRatio512	Decimator over sample ratio is 512.
kAFE_DecimatorOversampleRatio1024	Decimator over sample ratio is 1024.
kAFE_DecimatorOversampleRatio2048	Decimator over sample ratio is 2048.

enum afe_result_format_t

Enumerator
kAFE_ResultFormatLeft	Left justified result format.
kAFE_ResultFormatRight	Right justified result format.

enum afe_clock_divider_t

Enumerator
kAFE_ClockDivider1	Clock divided by 1.
kAFE_ClockDivider2	Clock divided by 2.
kAFE_ClockDivider4	Clock divided by 4.
kAFE_ClockDivider8	Clock divided by 8.
kAFE_ClockDivider16	Clock divided by 16.
kAFE_ClockDivider32	Clock divided by 32.
kAFE_ClockDivider64	Clock divided by 64.
kAFE_ClockDivider128	Clock divided by 128.
kAFE_ClockDivider256	Clock divided by 256.

enum afe_clock_source_t

Enumerator
kAFE_ClockSource0	Modulator clock source 0.
kAFE_ClockSource1	Modulator clock source 1.
kAFE_ClockSource2	Modulator clock source 2.
kAFE_ClockSource3	Modulator clock source 3.

enum afe_pga_gain_t

Enumerator
kAFE_PgaDisable	PGA disabled.
kAFE_PgaGain1	Input gained by 1.
kAFE_PgaGain2	Input gained by 2.
kAFE_PgaGain4	Input gained by 4.
kAFE_PgaGain8	Input gained by 8.
kAFE_PgaGain16	Input gained by 16.
kAFE_PgaGain32	Input gained by 32.

enum afe_bypass_mode_t

Enumerator
kAFE_BypassInternalClockPositiveEdge	Bypassed channel mode - internal clock selected, positive edge for registering data by the decimation filter.
kAFE_BypassExternalClockPositiveEdge	Bypassed channel mode - external clock selected, positive edge for registering data by the decimation filter.
kAFE_BypassInternalClockNegativeEdge	Bypassed channel mode - internal clock selected, negative edge for registering data by the decimation filter.
kAFE_BypassExternalClockNegativeEdge	Bypassed channel mode - external clock selected, negative edge for registering data by the decimation filter.
kAFE_BypassDisable	Normal channel mode.

Function Documentation

void AFE_Init	(	AFE_Type *	base,
		const afe_config_t *	config
	)

This function configures the AFE module for the configuration which are shared by all channels.

Parameters

base	AFE peripheral base address.
config	Pointer to structure of "afe_config_t".

void AFE_Deinit ( AFE_Type * base )

This function disables clock.

Parameters

base	AFE peripheral base address.

void AFE_GetDefaultConfig ( afe_config_t * config )

This function fills the afe_config_t structure with default settings. Defaut value are:

* config->enableLowPower   = false;
* config->resultFormat     = kAFE_ResultFormatRight;
* config->clockDivider     = kAFE_ClockDivider2;
* config->clockSource      = kAFE_ClockSource1;
* config->startupCount     = 2U;
* 

Parameters

config Pointer to structure of "afe_config_t".

static void AFE_SoftwareReset	(	AFE_Type *	base,
		bool	enable
	)

inlinestatic

This function is to reset all the ADCs, PGAs, decimation filters and clock configuration bits. When asserted as "false", all ADCs, PGAs and decimation filters are disabled. Clock Configuration bits are reset. When asserted as "true", all ADCs, PGAs and decimation filters are enabled.

Parameters

base	AFE peripheral base address.
enable	Assert the reset command.

static void AFE_Enable	(	AFE_Type *	base,
		bool	enable
	)

inlinestatic

This function enables AFE and filter.

Parameters

base	AFE peripheral base address.
enable	Enable the AFE module or not.

void AFE_SetChannelConfig	(	AFE_Type *	base,
		uint32_t	channel,
		const afe_channel_config_t *	config
	)

This function configures the selected AFE channel.

Parameters

base	AFE peripheral base address.
channel	AFE channel index.
config	Pointer to structure of "afe_channel_config_t".

void AFE_GetDefaultChannelConfig ( afe_channel_config_t * config )

This function fills the afe_channel_config_t structure with default settings. Default value are:

* config->enableHardwareTrigger      = false;
* config->enableContinuousConversion = false;
* config->channelMode                = kAFE_Normal;
* config->decimatorOversampleRatio   = kAFE_DecimatorOversampleRatio64;
* config->pgaGainSelect              = kAFE_PgaGain1;
* 

Parameters

config Pointer to structure of "afe_channel_config_t".

uint32_t AFE_GetChannelConversionValue	(	AFE_Type *	base,
		uint32_t	channel
	)

This function returns the raw conversion value of the selected channel.

Parameters

base	AFE peripheral base address.
channel	AFE channel index.

Returns: Conversion value.

Note: The returned value could be left or right adjusted according to the AFE module configuration.

static void AFE_DoSoftwareTriggerChannel	(	AFE_Type *	base,
		uint32_t	mask
	)

inlinestatic

This function triggers the AFE conversion by executing a software command. It starts the conversion on selected channels if the software trigger option is selected for the channels.

Parameters

base	AFE peripheral base address.
mask	AFE channel mask software trigger. The parameter can be combination of the following source if defined: kAFE_Channel0Trigger kAFE_Channel1Trigger kAFE_Channel2Trigger kAFE_Channel3Trigger

static uint32_t AFE_GetChannelStatusFlags ( AFE_Type * base )

inlinestatic

This function gets all AFE status.

Parameters

base	AFE peripheral base address.

Returns: the mask of these status flag bits.

void AFE_SetChannelPhaseDelayValue	(	AFE_Type *	base,
		uint32_t	channel,
		uint32_t	value
	)

This function sets the phase delays for channels. This delay is inserted before the trigger response of the decimation filters. The delay is used to provide a phase compensation between AFE channels in step of prescaled modulator clock periods.

Parameters

base	AFE peripheral base address.
channel	AFE channel index.
value	delay time value.

static void AFE_SetChannelPhasetDelayOk ( AFE_Type * base )

inlinestatic

This function should be called after all desired channel's delay registers are loaded. Values in channel's delay registers are active after calling this function and after the conversation starts.

Parameters

base	AFE peripheral base address.

static void AFE_EnableChannelInterrupts	(	AFE_Type *	base,
		uint32_t	mask
	)

inlinestatic

This function enables one channel interrupt.

Parameters

base	AFE peripheral base address.
mask	AFE channel interrupt mask. The parameter can be combination of the following source if defined: kAFE_Channel0InterruptEnable kAFE_Channel1InterruptEnable kAFE_Channel2InterruptEnable kAFE_Channel3InterruptEnable

static void AFE_DisableChannelInterrupts	(	AFE_Type *	base,
		uint32_t	mask
	)

inlinestatic

This function disables one channel interrupt.

Parameters

base	AFE peripheral base address.
mask	AFE channel interrupt mask. The parameter can be combination of the following source if defined: kAFE_Channel0InterruptEnable kAFE_Channel1InterruptEnable kAFE_Channel2InterruptEnable kAFE_Channel3InterruptEnable

static uint32_t AFE_GetEnabledChannelInterrupts ( AFE_Type * base )

inlinestatic

Parameters

base	AFE peripheral base address.

Returns: Return the mask of these interrupt enable/disable bits.

void AFE_EnableChannelDMA	(	AFE_Type *	base,
		uint32_t	mask,
		bool	enable
	)

This function enables/disables one channel DMA request.

Parameters

base	AFE peripheral base address.
mask	AFE channel dma mask.
enable	Pass true to enable interrupt, false to disable. The parameter can be combination of the following source if defined: kAFE_Channel0DMAEnable kAFE_Channel1DMAEnable kAFE_Channel2DMAEnable kAFE_Channel3DMAEnable

Overview

Function groups

Channel configuration structures

User configuration structures

AFE Initialization

AFE Conversion

Typical use case

AFE Initialization

AFE Conversion

Data Structures

Enumerations

Driver version

AFE Initialization

AFE Conversion

Data Structure Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation