Overview

The MCUXpresso SDK provides a peripheral driver for the Analog Comparator (CMP) module of MCUXpresso SDK devices.

The CMP driver is a basic comparator with advanced features. The APIs for the basic comparator enable the CMP to compare the two voltages of the two input channels and create the output of the comparator result. The APIs for advanced features can be used as the plug-in functions based on the basic comparator. They can process the comparator's output with hardware support.

Typical use case

Polling Configuration

int main(void)
{
    cmp_config_t mCmpConfigStruct;
    cmp_dac_config_t mCmpDacConfigStruct;
    // ...
    // Configures the comparator.
    CMP_Init(DEMO_CMP_INSTANCE);
    CMP_GetDefaultConfig(&mCmpConfigStruct);
    CMP_Configure(DEMO_CMP_INSTANCE, &mCmpConfigStruct);
    // Configures the DAC channel.
    mCmpDacConfigStruct.referenceVoltageSource = kCMP_VrefSourceVin2; // VCC.
    mCmpDacConfigStruct.DACValue = 32U; // Half voltage of logic high-level.
    CMP_SetDACConfig(DEMO_CMP_INSTANCE, &mCmpDacConfigStruct);
    CMP_SetInputChannels(DEMO_CMP_INSTANCE, DEMO_CMP_USER_CHANNEL, DEMO_CMP_DAC_CHANNEL);
    while (1)
    {
        if (0U != (kCMP_OutputAssertEventFlag & CMP_GetStatusFlags(DEMO_CMP_INSTANCE)))
        {
            // Do something.
        }
        else
        {
            // Do something.
        }
    }
}

Interrupt Configuration

volatile uint32_t g_CmpFlags = 0U;
// ...
void DEMO_CMP_IRQ_HANDLER_FUNC(void)
{
    g_CmpFlags = CMP_GetStatusFlags(DEMO_CMP_INSTANCE);
    CMP_ClearStatusFlags(DEMO_CMP_INSTANCE, kCMP_OutputRisingEventFlag | kCMP_OutputFallingEventFlag);
    if (0U != (g_CmpFlags & kCMP_OutputRisingEventFlag))
    {
        // Do something.
    }
    else if (0U != (g_CmpFlags & kCMP_OutputFallingEventFlag))
    {
        // Do something.
    }
}
int main(void)
{
    cmp_config_t mCmpConfigStruct;
    cmp_dac_config_t mCmpDacConfigStruct;
    // ...
    EnableIRQ(DEMO_CMP_IRQ_ID);
    // ...
    // Configures the comparator.
    CMP_Init(DEMO_CMP_INSTANCE);
    CMP_GetDefaultConfig(&mCmpConfigStruct);
    CMP_Configure(DEMO_CMP_INSTANCE, &mCmpConfigStruct);
    // Configures the DAC channel.
    mCmpDacConfigStruct.referenceVoltageSource = kCMP_VrefSourceVin2; // VCC.
    mCmpDacConfigStruct.DACValue = 32U; // Half voltage of logic high-level.
    CMP_SetDACConfig(DEMO_CMP_INSTANCE, &mCmpDacConfigStruct);
    CMP_SetInputChannels(DEMO_CMP_INSTANCE, DEMO_CMP_USER_CHANNEL, DEMO_CMP_DAC_CHANNEL);
    // Enables the output rising and falling interrupts.
    CMP_EnableInterrupts(DEMO_CMP_INSTANCE, kCMP_OutputRisingInterruptEnable | kCMP_OutputFallingInterruptEnable);
    while (1)
    {
    }
}

Data Structures
struct	cmp_config_t
	Configures the comparator. More...

struct	cmp_filter_config_t
	Configures the filter. More...

struct	cmp_dac_config_t
	Configures the internal DAC. More...

Enumerations
enum	_cmp_interrupt_enable { kCMP_OutputRisingInterruptEnable = CMP_SCR_IER_MASK, kCMP_OutputFallingInterruptEnable = CMP_SCR_IEF_MASK }
	Interrupt enable/disable mask. More...

enum	_cmp_status_flags { kCMP_OutputRisingEventFlag = CMP_SCR_CFR_MASK, kCMP_OutputFallingEventFlag = CMP_SCR_CFF_MASK, kCMP_OutputAssertEventFlag = CMP_SCR_COUT_MASK }
	Status flags' mask. More...

enum	cmp_hysteresis_mode_t { kCMP_HysteresisLevel0 = 0U, kCMP_HysteresisLevel1 = 1U, kCMP_HysteresisLevel2 = 2U, kCMP_HysteresisLevel3 = 3U }
	CMP Hysteresis mode. More...

enum	cmp_reference_voltage_source_t { kCMP_VrefSourceVin1 = 0U, kCMP_VrefSourceVin2 = 1U }
	CMP Voltage Reference source. More...

Driver version
#define	FSL_CMP_DRIVER_VERSION (MAKE_VERSION(2, 0, 0))
	CMP driver version 2.0.0. More...

Initialization
void	CMP_Init (CMP_Type base, const cmp_config_t config)
	Initializes the CMP. More...

void	CMP_Deinit (CMP_Type *base)
	De-initializes the CMP module. More...

static void	CMP_Enable (CMP_Type *base, bool enable)
	Enables/disables the CMP module. More...

void	CMP_GetDefaultConfig (cmp_config_t *config)
	Initializes the CMP user configuration structure. More...

void	CMP_SetInputChannels (CMP_Type *base, uint8_t positiveChannel, uint8_t negativeChannel)
	Sets the input channels for the comparator. More...

Advanced Features
void	CMP_EnableDMA (CMP_Type *base, bool enable)
	Enables/disables the DMA request for rising/falling events. More...

void	CMP_SetFilterConfig (CMP_Type base, const cmp_filter_config_t config)
	Configures the filter. More...

void	CMP_SetDACConfig (CMP_Type base, const cmp_dac_config_t config)
	Configures the internal DAC. More...

void	CMP_EnableInterrupts (CMP_Type *base, uint32_t mask)
	Enables the interrupts. More...

void	CMP_DisableInterrupts (CMP_Type *base, uint32_t mask)
	Disables the interrupts. More...

Results
uint32_t	CMP_GetStatusFlags (CMP_Type *base)
	Gets the status flags. More...

void	CMP_ClearStatusFlags (CMP_Type *base, uint32_t mask)
	Clears the status flags. More...

Data Structure Documentation

struct cmp_config_t

Data Fields
bool	enableCmp
	Enable the CMP module. More...

cmp_hysteresis_mode_t	hysteresisMode
	CMP Hysteresis mode. More...

bool	enableHighSpeed
	Enable High-speed (HS) comparison mode. More...

bool	enableInvertOutput
	Enable the inverted comparator output. More...

bool	useUnfilteredOutput
	Set the compare output(COUT) to equal COUTA(true) or COUT(false). More...

bool	enablePinOut
	The comparator output is available on the associated pin. More...

bool	enableTriggerMode
	Enable the trigger mode. More...

Field Documentation

bool cmp_config_t::enableCmp

cmp_hysteresis_mode_t cmp_config_t::hysteresisMode

bool cmp_config_t::enableHighSpeed

bool cmp_config_t::enableInvertOutput

bool cmp_config_t::useUnfilteredOutput

bool cmp_config_t::enablePinOut

bool cmp_config_t::enableTriggerMode

struct cmp_filter_config_t

Data Fields
uint8_t	filterCount
	Filter Sample Count. More...

uint8_t	filterPeriod
	Filter Sample Period. More...

Field Documentation

uint8_t cmp_filter_config_t::filterCount

Available range is 1-7; 0 disables the filter.

uint8_t cmp_filter_config_t::filterPeriod

The divider to the bus clock. Available range is 0-255.

struct cmp_dac_config_t

Data Fields
cmp_reference_voltage_source_t	referenceVoltageSource
	Supply voltage reference source. More...

uint8_t	DACValue
	Value for the DAC Output Voltage. More...

Field Documentation

cmp_reference_voltage_source_t cmp_dac_config_t::referenceVoltageSource

uint8_t cmp_dac_config_t::DACValue

Available range is 0-63.

Macro Definition Documentation

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

Enumeration Type Documentation

enum _cmp_interrupt_enable

Enumerator
kCMP_OutputRisingInterruptEnable	Comparator interrupt enable rising.
kCMP_OutputFallingInterruptEnable	Comparator interrupt enable falling.

enum _cmp_status_flags

Enumerator
kCMP_OutputRisingEventFlag	Rising-edge on the comparison output has occurred.
kCMP_OutputFallingEventFlag	Falling-edge on the comparison output has occurred.
kCMP_OutputAssertEventFlag	Return the current value of the analog comparator output.

enum cmp_hysteresis_mode_t

Enumerator
kCMP_HysteresisLevel0	Hysteresis level 0.
kCMP_HysteresisLevel1	Hysteresis level 1.
kCMP_HysteresisLevel2	Hysteresis level 2.
kCMP_HysteresisLevel3	Hysteresis level 3.

enum cmp_reference_voltage_source_t

Enumerator
kCMP_VrefSourceVin1	Vin1 is selected as a resistor ladder network supply reference Vin.
kCMP_VrefSourceVin2	Vin2 is selected as a resistor ladder network supply reference Vin.

Function Documentation

void CMP_Init	(	CMP_Type *	base,
		const cmp_config_t *	config
	)

This function initializes the CMP module. The operations included are as follows.

Enabling the clock for CMP module.
Configuring the comparator.
Enabling the CMP module. Note that for some devices, multiple CMP instances share the same clock gate. In this case, to enable the clock for any instance enables all CMPs. See the appropriate MCU reference manual for the clock assignment of the CMP.

Parameters

base	CMP peripheral base address.
config	Pointer to the configuration structure.

void CMP_Deinit ( CMP_Type * base )

This function de-initializes the CMP module. The operations included are as follows.

Disabling the CMP module.
Disabling the clock for CMP module.

This function disables the clock for the CMP. Note that for some devices, multiple CMP instances share the same clock gate. In this case, before disabling the clock for the CMP, ensure that all the CMP instances are not used.

Parameters

base	CMP peripheral base address.

static void CMP_Enable	(	CMP_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	CMP peripheral base address.
enable	Enables or disables the module.

void CMP_GetDefaultConfig ( cmp_config_t * config )

This function initializes the user configuration structure to these default values.

*   config->enableCmp           = true;
*   config->hysteresisMode      = kCMP_HysteresisLevel0;
*   config->enableHighSpeed     = false;
*   config->enableInvertOutput  = false;
*   config->useUnfilteredOutput = false;
*   config->enablePinOut        = false;
*   config->enableTriggerMode   = false;
* 

Parameters

config Pointer to the configuration structure.

void CMP_SetInputChannels	(	CMP_Type *	base,
		uint8_t	positiveChannel,
		uint8_t	negativeChannel
	)

This function sets the input channels for the comparator. Note that two input channels cannot be set the same way in the application. When the user selects the same input from the analog mux to the positive and negative port, the comparator is disabled automatically.

Parameters

base	CMP peripheral base address.
positiveChannel	Positive side input channel number. Available range is 0-7.
negativeChannel	Negative side input channel number. Available range is 0-7.

void CMP_EnableDMA	(	CMP_Type *	base,
		bool	enable
	)

This function enables/disables the DMA request for rising/falling events. Either event triggers the generation of the DMA request from CMP if the DMA feature is enabled. Both events are ignored for generating the DMA request from the CMP if the DMA is disabled.

Parameters

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

void CMP_SetFilterConfig	(	CMP_Type *	base,
		const cmp_filter_config_t *	config
	)

Parameters

base	CMP peripheral base address.
config	Pointer to the configuration structure.

void CMP_SetDACConfig	(	CMP_Type *	base,
		const cmp_dac_config_t *	config
	)

Parameters

base	CMP peripheral base address.
config	Pointer to the configuration structure. "NULL" disables the feature.

void CMP_EnableInterrupts	(	CMP_Type *	base,
		uint32_t	mask
	)

Parameters

base	CMP peripheral base address.
mask	Mask value for interrupts. See "_cmp_interrupt_enable".

void CMP_DisableInterrupts	(	CMP_Type *	base,
		uint32_t	mask
	)

Parameters

base	CMP peripheral base address.
mask	Mask value for interrupts. See "_cmp_interrupt_enable".

uint32_t CMP_GetStatusFlags ( CMP_Type * base )

Parameters

base	CMP peripheral base address.

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

void CMP_ClearStatusFlags	(	CMP_Type *	base,
		uint32_t	mask
	)

Parameters

base	CMP peripheral base address.
mask	Mask value for the flags. See "_cmp_status_flags".

Overview

Typical use case

Polling Configuration

Interrupt Configuration

Data Structures

Enumerations

Driver version

Initialization

Advanced Features

Results

Data Structure Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation