HRCAP Module¶

The High Resolution Enhanced Capture (HRCAP) API provides a set of functions for configuring and using the high resolution capability of the HRCAP module. The functions provided allow for the setup and configuration of the high resolution capture capability. The necessary APIs to configure the high resolution capture calibration hardware are also provided.

group hrcap_api

Defines

HRCAP_GLOBAL_CALIBRATION_INTERRUPT 0x1U¶: Global calibration interrupt flag

HRCAP_CALIBRATION_DONE 0x2U¶: Calibration done flag

HRCAP_CALIBRATION_PERIOD_OVERFLOW 0x4U¶: Calibration period overflow flag

Enums

enum HRCAP_CalibrationClockSource¶

Values that can be passed to HRCAP_getCalibrationClockPeriod() as the clockSource parameter.

Values:

enumerator HRCAP_CALIBRATION_CLOCK_SYSCLK = 0x0¶: Use SYSCLK for period match.

enumerator HRCAP_CALIBRATION_CLOCK_HRCLK = 0x4¶: Use HRCLK for period match.

enum HRCAP_ContinuousCalibrationMode¶

Values that can be passed to HRCAP_setCalibrationMode(), as the continuousMode parameter.

Values:

enumerator HRCAP_CONTINUOUS_CALIBRATION_DISABLED = 0x00¶: Continuous calibration disabled.

enumerator HRCAP_CONTINUOUS_CALIBRATION_ENABLED = 0x20¶: Continuous calibration enabled.

Functions

void HRCAP_enableHighResolution(uint32_t base)¶

enables HRCAP.

This function enables High Resolution Capture module.

Parameters

base: is the base address of the HRCAP instance used.

Note: High resolution clock must be enabled before High Resolution Module is enabled.
Return: None.

void HRCAP_disableHighResolution(uint32_t base)¶

Disables HRCAP.

This function disable High Resolution Capture module.

Parameters

base: is the base address of the HRCAP instance used.

Return: None.

void HRCAP_enableHighResolutionClock(uint32_t base)¶

Enables high resolution clock.

This function enables High Resolution clock.

Parameters

base: is the base address of the HRCAP instance used.

Return: None.

void HRCAP_disbleHighResolutionClock(uint32_t base)¶

Disables High resolution clock.

This function disables High Resolution clock.

Parameters

base: is the base address of the HRCAP instance used.

Return: None.

void HRCAP_startCalibration(uint32_t base)¶

Starts calibration.

This function starts calibration.

Parameters

base: is the base address of the HRCAP instance used.

Return: None.

void HRCAP_setCalibrationMode(uint32_t base)¶

Sets the calibration mode.

This function sets the the calibration mode by turning on continuous calibration.

Parameters

base: is the base address of the HRCAP instance used.

Return: None.

void HRCAP_enableCalibrationInterrupt(uint32_t base, uint16_t intFlags)¶

Enables calibration interrupt.

This function enables HRCAP calibration interrupt flags. Valid values for intFlags are:

HRCAP_CALIBRATION_DONE - Calibration done interrupt.
HRCAP_CALIBRATION_PERIOD_OVERFLOW - Calibration period overflow check interrupt.

Return
None.

Parameters

base: is the base address of the HRCAP module.
intFlags: is the calibration interrupt flags to be enabled.

void HRCAP_disableCalibrationInterrupt(uint32_t base, uint16_t intFlags)¶

Disables calibration interrupt source.

This function disables HRCAP calibration interrupt flags. Valid values for intFlags are:

HRCAP_CALIBRATION_DONE - Calibration done interrupt.
HRCAP_CALIBRATION_PERIOD_OVERFLOW - Calibration period check interrupt.

Return
None.

Parameters

base: is the base address of the HRCAP module.
intFlags: is the calibration interrupt flags to be disabled.

uint16_t HRCAP_getCalibrationFlags(uint32_t base)¶

Returns the calibration interrupt source.

This function returns the HRCAP calibration interrupt source.

Parameters

base: is the base address of the HRCAP module.

Return

Returns the HRCAP interrupt that has occurred. The following are valid return values.

HRCAP_GLOBAL_CALIBRATION_INTERRUPT - Global calibration interrupt.
HRCAP_CALIBRATION_DONE - Calibration done interrupt.
HRCAP_CALIBRATION_PERIOD_OVERFLOW - Calibration period overflow interrupt.

Note

- User can check if a combination of the interrupts have occurred by ORing the above return values.

void HRCAP_clearCalibrationFlags(uint32_t base, uint16_t flags)¶

Clears calibration flags.

This function clears HRCAP calibration flags. The following are valid values for flags.

HRCAP_GLOBAL_CALIBRATION_INTERRUPT - Global calibration interrupt.
HRCAP_CALIBRATION_DONE - Calibration done flag.
HRCAP_CALIBRATION_PERIOD_OVERFLOW - Calibration period overflow flag.

Parameters

base: is the base address of the HRCAP module.
flags: is the calibration flags to be cleared.

Return: None.

bool HRCAP_isCalibrationBusy(uint32_t base)¶

Return the Calibration status

This function returns the calibration status.

Parameters

base: is the base address of the HRCAP instance used.

Return: This functions returns true if the calibration is in process,false if there is no active calibration.

void HRCAP_forceCalibrationFlags(uint32_t base, uint16_t flag)¶

Force a software based calibration

This function forces a software based calibration done flag. The following are valid values for flag.

HRCAP_CALIBRATION_DONE - Calibration done flag.
HRCAP_CALIBRATION_PERIOD_OVERFLOW - Calibration period overflow flag.

Parameters

base: is the base address of the HRCAP instance used.
flag: is the calibration flag source.

Return: None.

void HRCAP_setCalibrationPeriod(uint32_t base, uint32_t sysclkHz)¶

Sets the calibration period count

This function sets the calibration period count value to achieve a period of 1.6 milliseconds given the SYSCLK frequency in Hz (the

sysclkHz parameter).

Parameters

base: is the base address of the HRCAP instance used.
sysclkHz: is the rate of the SYSCLK in Hz.

Return: None.

uint32_t HRCAP_getCalibrationClockPeriod(uint32_t base, HRCAP_CalibrationClockSource clockSource)¶

Returns the calibration clock period

This function returns the period match value of the calibration clock. The return value has a valid count when a period match occurs.

Parameters

base: is the base address of the HRCAP instance used.
clockSource: is the calibration clock source (HRCAP_CALIBRATION_CLOCK_SYSCLK or HRCAP_CALIBRATION_CLOCK_HRCLK).

Return: This function returns the captured value of the clock counter specified by clockSource.

float32_t HRCAP_getScaleFactor(uint32_t base)¶

Calculates the scale factor

This function reads the SYSCLK and HRCLK calibration periods and then uses them to calculate the scale factor.

Parameters

base: is the base address of the HRCAP instance used.

Return: This function returns the calculated scale factor.

float32_t HRCAP_convertEventTimeStampNanoseconds(uint32_t timeStamp, float32_t scaleFactor)¶

Returns event time stamp in nanoseconds

This function converts a raw CAP time stamp (the

timeStamp parameter) to nanoseconds using the provided scale factor (the scaleFactor parameter).

Parameters

timeStamp: is a raw time stamp count returned by ECAP_getEventTimeStamp().
scaleFactor: is the calculated scale factor returned by HRCAP_getScaleFactor().

Return: Returns the converted time stamp in nanoseconds.

The code for this module is contained in driverlib/hrcap.c, with driverlib/hrcap.h containing the API declarations for use by applications.