DCC Module

The dual clock comparator (DCC) API provides a set of functions for configuring and using the DCC module. The functions provided allow for setting up the module including the operating modes, configuring the clock sources, enabling interrupt signals, and reading the various clock counters.

group dcc_api

Defines

DCC_VALIDSEED_MIN 4U
DCC_VALIDSEED_MAX 0xFFFFU
DCC_COUNTSEED_MIN 1U
DCC_COUNTSEED_MAX 0xFFFFFU
DCC_ENABLE_VALUE (0xAU)
DCC_DISABLE_VALUE (0x5U)
DCC_REG_WORD_MASK (0xFFFFU)
DCC_REG_BYTE_MASK (0x7FU)
DCC_SEED_REG_MASK (0xFFF0U)
DCC_SEED_CNT_MASK (0xF0000U)

Enums

enum DCC_SingleShotMode

The following are defines for the mode parameter of the DCC_enableSingleShotMode() function.

Values:

enumerator DCC_MODE_COUNTER_ZERO = 0xA00U

Use to stop counting when counter0 and valid0 both reach zero.

enumerator DCC_MODE_COUNTER_ONE = 0xB00U

Use to stop counting when counter1 reaches zero.

enum DCC_Count1ClockSource

The following are defines for the source parameter of the DCC_setCounter1ClkSource() function.

Values:

enumerator DCC_COUNT1SRC_PLL = 0x0U

PLL021SSP Clock Out Source.

enumerator DCC_COUNT1SRC_INTOSC1 = 0x2U

Internal Oscillator1 Clock Source.

enumerator DCC_COUNT1SRC_INTOSC2 = 0x3U

Internal Oscillator2 Clock Source.

enumerator DCC_COUNT1SRC_SYSCLK = 0x6U

System Clock Source.

enumerator DCC_COUNT1SRC_AUXCLKIN = 0xAU

AUX Clock input Source.

enumerator DCC_COUNT1SRC_EPWM = 0xBU

EPWM Clock Source.

enumerator DCC_COUNT1SRC_ADCCLK = 0xDU

ADC Clock Source.

enumerator DCC_COUNT1SRC_WDCLK = 0xEU

Watch Dog Clock Source.

enumerator DCC_COUNT1SRC_CANX = 0xFU

CANxBIT Clock Source.

enumerator DCC_COUNT1SRC_SYSAPLL_CLK_AUX = 0x16U

System APLL Aux Clk.

enum DCC_Count0ClockSource

The following are defines for the source parameter of the DCC_setCounter0ClkSource() function.

Values:

enumerator DCC_COUNT0SRC_XTAL = 0x0U

Accurate Clock Source.

enumerator DCC_COUNT0SRC_INTOSC1 = 0x1U

Internal Oscillator1 Clock Source.

enumerator DCC_COUNT0SRC_INTOSC2 = 0x2U

Internal Oscillator2 Clock Source.

enumerator DCC_COUNT0SRC_TCK = 0x4U

Preliminary Clock Source.

enumerator DCC_COUNT0SRC_SYSCLK = 0x5U

System Clock Source.

enumerator DCC_COUNT0SRC_AUXCLK = 0x8U

AUX Clock Source.

Functions

void DCC_enableModule(uint32_t base)

Enables the DCC module.

This function starts the DCC counter operation.

Parameters

  • base: is the DCC module base address

Return

None.

void DCC_disableModule(uint32_t base)

Disable the DCC module.

This function stops the DCC counter operation.

Parameters

  • base: is the DCC module base address

Return

None.

void DCC_enableErrorSignal(uint32_t base)

Enable DCC Error Signal

This function enables the error signal interrupt.

Parameters

  • base: is the DCC module base address

Return

None.

void DCC_enableDoneSignal(uint32_t base)

Enable DCC Done Signal

This function enables the done signal interrupt.

Parameters

  • base: is the DCC module base address

Return

None.

void DCC_disableErrorSignal(uint32_t base)

Disable DCC Error Signal

This function disables the error signal interrupt.

Parameters

  • base: is the DCC module base address

Return

None.

void DCC_disableDoneSignal(uint32_t base)

Disable DCC Done Signal

This function disables the done signal interrupt.

Parameters

  • base: is the DCC module base address

Return

None.

void DCC_enableSingleShotMode(uint32_t base, DCC_SingleShotMode mode)

Enable DCC Single-Shot Mode

This function enables the single-shot mode and sets the operation mode.

Parameters

  • base: is the DCC module base address

  • mode: is the selected Single-Shot operation mode

The mode parameter can have one of two values:

  • DCC_MODE_COUNTER_ZERO - Stops counting when counter0 and valid0 both reach zero

  • DCC_MODE_COUNTER_ONE - Stops counting when counter1 reaches zero

Return

None.

void DCC_disableSingleShotMode(uint32_t base)

Disable DCC Single-Shot Mode

This function disables the DCC Single-Shot operation mode

Parameters

  • base: is the DCC module base address

Return

None.

bool DCC_getErrorStatus(uint32_t base)

Get Error Flag Status

This function gets the error flag status.

Parameters

  • base: is the DCC module base address

Return

Returns true if an error has occurred, false if no errors have occurred.

bool DCC_getSingleShotStatus(uint32_t base)

Get Single-Shot Done Flag Status

This function gets the single-shot done flag status.

Parameters

  • base: is the DCC module base address

Return

Returns true if single-shot mode has completed, false if single-shot mode has not completed.

void DCC_clearErrorFlag(uint32_t base)

Clear Error Status Flag

This function clears the DCC error status flag.

Parameters

  • base: is the DCC module base address

Return

None.

void DCC_clearDoneFlag(uint32_t base)

Clear Single-Shot Done Status Flag

This function clears the DCC single-shot done status flag.

Parameters

  • base: is the DCC module base address

Return

None.

uint32_t DCC_getCounter0Value(uint32_t base)

Get Current Value of Counter 0

This function gets current value of counter 0.

Parameters

  • base: is the DCC module base address

Note

Reads of the counter value may not be exact since the read operation is synchronized to the vbus clock.

Return

Returns the current value of counter 0.

uint16_t DCC_getValidCounter0Value(uint32_t base)

Get Current Value of the Valid Duration Counter for Counter 0

This function gets current value of the valid duration counter for counter 0.

Parameters

  • base: is the DCC module base address

Note

Reads of the counter value may not be exact since the read operation is synchronized to the vbus clock.

Return

Returns the current value of the valid duration counter.

uint32_t DCC_getCounter1Value(uint32_t base)

Get Current Value of Counter 1

This function gets current value of counter 1.

Parameters

  • base: is the DCC module base address

Note

Reads of the counter value may not be exact since the read operation is synchronized to the vbus clock.

Return

Returns the current value of counter 1.

void DCC_setCounter1ClkSource(uint32_t base, DCC_Count1ClockSource source)

Set Counter 1 Clock Source

This function sets the counter 1 clock source.

Parameters

  • base: is the DCC module base address

  • source: is the selected clock source for counter 1

The source parameter can have one of following values:

  • DCC_COUNT1SRC_PLL - PLL021SSP Clock Out Source

  • DCC_COUNT1SRC_INTOSC1 - Internal Oscillator1 Clock Source

  • DCC_COUNT1SRC_INTOSC2 - Internal Oscillator2 Clock Source

  • DCC_COUNT1SRC_SYSCLK - System Clock Source

  • DCC_COUNT1SRC_AUXCLKIN - AUX Clock input Source

  • DCC_COUNT1SRC_EPWM - EPWM Clock Source

  • DCC_COUNT1SRC_ADCCLK - ADC Clock Source

  • DCC_COUNT1SRC_WDCLK - Watch Dog Clock Source

  • DCC_COUNT1SRC_CANX - CANxBIT Clock Source

  • DCC_COUNT1SRC_SYSAPLL_CLK_AUX - System APLL Aux Clk

Return

None.

void DCC_setCounter0ClkSource(uint32_t base, DCC_Count0ClockSource source)

Set Counter 0 Clock Source

This function sets the counter 0 clock source.

Parameters

  • base: is the DCC module base address

  • source: is the selected clock source for counter 0

The source parameter can have one of following values:

  • DCC_COUNT0SRC_XTAL - Accurate Clock Source

  • DCC_COUNT0SRC_INTOSC1 - Internal Oscillator1 Clock Source

  • DCC_COUNT0SRC_INTOSC2 - Internal Oscillator2 Clock Source

  • DCC_COUNT0SRC_TCK - Preliminary Clock Source

  • DCC_COUNT0SRC_SYSCLK - System Clock Source

  • DCC_COUNT0SRC_AUXCLK - AUX Clock Source

Return

None.

uint16_t DCC_getCounter1ClkSource(uint32_t base)

Get Counter 1 Clock Source

This function gets the counter 1 clock source.

Parameters

  • base: is the DCC module base address

Return

Returns one of the following enumerated source values:

  • DCC_COUNT1SRC_PLL - PLL021SSP Clock Out Source

  • DCC_COUNT1SRC_INTOSC1 - Internal Oscillator1 Clock Source

  • DCC_COUNT1SRC_INTOSC2 - Internal Oscillator2 Clock Source

  • DCC_COUNT1SRC_SYSCLK - System Clock Source

  • DCC_COUNT1SRC_AUXCLKIN - AUX Clock input Source

  • DCC_COUNT1SRC_EPWM - EPWM Clock Source

  • DCC_COUNT1SRC_ADCCLK - ADC Clock Source

  • DCC_COUNT1SRC_WDCLK - Watch Dog Clock Source

  • DCC_COUNT1SRC_CANX - CANxBIT Clock Source

  • DCC_COUNT1SRC_SYSAPLL_CLK_AUX - System APLL Aux Clk

uint16_t DCC_getCounter0ClkSource(uint32_t base)

Get Counter 0 Clock Source

This function gets the counter 0 clock source.

Parameters

  • base: is the DCC module base address

Return

Returns one of the following enumerated source values:

  • DCC_COUNT0SRC_XTAL - Accurate Clock Source

  • DCC_COUNT0SRC_INTOSC1 - Internal Oscillator1 Clock Source

  • DCC_COUNT0SRC_INTOSC2 - Internal Oscillator2 Clock Source

  • DCC_COUNT0SRC_TCK - Preliminary Clock Source

  • DCC_COUNT0SRC_SYSCLK - System Clock Source

  • DCC_COUNT0SRC_AUXCLK - AUX Clock Source

void DCC_setCounterSeeds(uint32_t base, uint32_t counter0, uint32_t validCounter0, uint32_t counter1)

Set the seed values

This function sets the seed values for Counter 0, Valid Duration Counter 0, and Counter 1.

Parameters

  • base: is the DCC module base address

  • counter0: sets the seed value that gets loaded into Counter 0

  • validCounter0: sets the seed value that gets loaded into the valid duration counter for Counter 0

  • counter1: sets the seed value that gets loaded into Counter 1

Note

  1. Operating DCC with ‘0’ set as the seed value for Counter 0, Valid Duration Counter 0, and/or Counter 1 will result in undefined operation.

  2. The Valid Duration Counter 0 is designed to be at least four cycles wide and shouldn’t be programmed with a value less than ‘4’.

Return

None.

bool DCC_verifyClockFrequency(uint32_t base, DCC_Count1ClockSource clock1, float32_t freq1, DCC_Count0ClockSource clock0, float32_t freq0, float32_t tolerance, float32_t freqerr, float32_t freq_sysclk)

Verify the frequency of a clock source using a reference clock

This function verifies the frequency of the specified clock using a reference clock.

Parameters

  • base: is the DCC module base address

  • clock1: is the clock source to be verified

  • freq1: is the frequency of the clock source to be verified

  • clock0: is the reference clock

  • freq0: is the frequency of the reference clock

  • tolerance: is the DCC error tolerance in percentage

  • freqerr: is the allowable Frequency Tolerance in percentage

  • freq_sysclk: is the frequency of the system clock

Note

Make sure that the frequency of all the clocks are in the same unit

Return

Returns true if the actual frequency of clock1 is matching freq1, false otherwise

float32_t DCC_measureClockFrequency(uint32_t base, DCC_Count1ClockSource clock1, DCC_Count0ClockSource clock0, float32_t freq0, float32_t tolerance, float32_t freqerr, float32_t freq_sysclk)

Measure the frequency of a clock source using a reference clock

This function measures the frequency of the specified clock using a reference clock.

Parameters

  • base: is the DCC module base address

  • clock1: is the clock source to be measured

  • clock0: is the reference clock

  • freq0: is the frequency of the reference clock

  • tolerance: is the DCC error tolerance in percentage

  • freqerr: is the allowable Frequency Tolerance in percentage

  • freq_sysclk: is the frequency of the system clock

Note

Make sure that the frequency of all the clocks are in the same unit

Return

Measured clock frequency

void DCC_continuousMonitor(uint32_t base, DCC_Count1ClockSource clock1, float32_t freq1, DCC_Count0ClockSource clock0, float32_t freq0, float32_t tolerance, float32_t freqerr, float32_t freq_sysclk)

Continuously monitor the frequency of a clock source using a reference clock

This function continuously monitors the frequency of the specified clock using a reference clock. An error signal is generated if the frequency ratio is altered.

Parameters

  • base: is the DCC module base address

  • clock1: is the clock source to be verified

  • freq1: is the frequency of the clock source to be verified

  • clock0: is the reference clock

  • freq0: is the frequency of the reference clock

  • tolerance: is the DCC error tolerance in percentage

  • freqerr: is the allowable Frequency Tolerance in percentage

  • freq_sysclk: is the frequency of the system clock

Note

Make sure that the frequency of all the clocks are in the same unit

Note

This function does not enable the DCC interrupt. The user application must enable it to trigger an intetrupt when an error is detected.

Return

Returns None

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