EQEP Module¶

The enhanced quadrature encoder pulse (eQEP) API provides a set of functions to configure an interface to an encoder. The functions provide the ability to configure the device’s eQEP module to properly decode incoming pulse signals, to configure module outputs, and to get direction, position, and speed information. There are also APIs to setup the possible interrupt events that the module can generate.

group eqep_api

Defines

EQEP_CONFIG_QUADRATURE 0x0000U¶: Quadrature-clock mode.

EQEP_CONFIG_CLOCK_DIR 0x4000U¶: Direction-count mode.

EQEP_CONFIG_UP_COUNT 0x8000U¶: Up-count mode, QDIR = 1.

EQEP_CONFIG_DOWN_COUNT 0xC000U¶: Down-count mode, QDIR = 0.

EQEP_CONFIG_2X_RESOLUTION 0x0000U¶: Count rising and falling edge.

EQEP_CONFIG_1X_RESOLUTION 0x0800U¶: Count rising edge only.

EQEP_CONFIG_NO_SWAP 0x0000U¶: Do not swap QEPA and QEPB.

EQEP_CONFIG_SWAP 0x0400U¶: Swap QEPA and QEPB.

EQEP_COMPARE_NO_SYNC_OUT 0x0000U¶: Disable sync output.

EQEP_COMPARE_IDX_SYNC_OUT 0x2000U¶: Sync output on index pin.

EQEP_COMPARE_STROBE_SYNC_OUT 0x3000U¶: Sync output on strobe pin.

EQEP_COMPARE_NO_SHADOW 0x0000U¶: Disable shadow of QPOSCMP.

EQEP_COMPARE_LOAD_ON_ZERO 0x8000U¶: Load on QPOSCNT = 0.

EQEP_COMPARE_LOAD_ON_MATCH 0xC000U¶: Load on QPOSCNT = QPOSCMP.

EQEP_INT_GLOBAL 0x0001U¶: Global interrupt flag.

EQEP_INT_POS_CNT_ERROR 0x0002U¶: Position counter error.

EQEP_INT_PHASE_ERROR 0x0004U¶: Quadrature phase error.

EQEP_INT_DIR_CHANGE 0x0008U¶: Quadrature direction change.

EQEP_INT_WATCHDOG 0x0010U¶: Watchdog time-out.

EQEP_INT_UNDERFLOW 0x0020U¶: Position counter underflow.

EQEP_INT_OVERFLOW 0x0040U¶: Position counter overflow.

EQEP_INT_POS_COMP_READY 0x0080U¶: Position-compare ready.

EQEP_INT_POS_COMP_MATCH 0x0100U¶: Position-compare match.

EQEP_INT_STROBE_EVNT_LATCH 0x0200U¶: Strobe event latch.

EQEP_INT_INDEX_EVNT_LATCH 0x0400U¶: Index event latch.

EQEP_INT_UNIT_TIME_OUT 0x0800U¶: Unit time-out.

EQEP_INT_QMA_ERROR 0x1000U¶: QMA error.

EQEP_STS_UNIT_POS_EVNT 0x0080U¶: Unit position event detected.

EQEP_STS_DIR_ON_1ST_IDX 0x0040U¶: Direction was clockwise on first index event.

EQEP_STS_DIR_FLAG 0x0020U¶: Direction is CW (forward)

EQEP_STS_DIR_LATCH 0x0010U¶: Direction was CW on index.

EQEP_STS_CAP_OVRFLW_ERROR 0x0008U¶: Capture timer overflow.

EQEP_STS_CAP_DIR_ERROR 0x0004U¶: Direction changed between position capture events.

EQEP_STS_1ST_IDX_FLAG 0x0002U¶: First index pulse occurred.

EQEP_STS_POS_CNT_ERROR 0x0001U¶: Position counter error.

EQEP_LATCH_CNT_READ_BY_CPU 0x0000U¶: On position counter read.

EQEP_LATCH_UNIT_TIME_OUT 0x0004U¶: On unit time-out event.

EQEP_LATCH_RISING_STROBE 0x0000U¶: On rising edge of strobe.

EQEP_LATCH_EDGE_DIR_STROBE 0x0040U¶: On rising edge when clockwise, on falling when counter clockwise.

EQEP_LATCH_RISING_INDEX 0x0010U¶: On rising edge of index.

EQEP_LATCH_FALLING_INDEX 0x0020U¶: On falling edge of index.

EQEP_LATCH_SW_INDEX_MARKER 0x0030U¶: On software index marker.

EQEP_INIT_DO_NOTHING 0x0000U¶: Action is disabled.

EQEP_INIT_RISING_STROBE 0x0800U¶: On rising edge of strobe.

EQEP_INIT_EDGE_DIR_STROBE 0x0C00U¶: On rising edge when clockwise, on falling when counter clockwise.

EQEP_INIT_RISING_INDEX 0x0200U¶: On rising edge of index.

EQEP_INIT_FALLING_INDEX 0x0300U¶: On falling edge of index.

Enums

enum EQEP_PositionResetMode¶

Values that can be passed to EQEP_setPositionCounterConfig() as the mode parameter.

Values:

enumerator EQEP_POSITION_RESET_IDX = 0x0000¶: Reset position on index pulse.

enumerator EQEP_POSITION_RESET_MAX_POS = 0x1000¶: Reset position on maximum position.

enumerator EQEP_POSITION_RESET_1ST_IDX = 0x2000¶: Reset position on the first index pulse.

enumerator EQEP_POSITION_RESET_UNIT_TIME_OUT = 0x3000¶: Reset position on a unit time event.

enum EQEP_CAPCLKPrescale¶

Values that can be passed to EQEP_setCaptureConfig() as the capPrescale parameter. CAPCLK is the capture timer clock frequency.

Values:

enumerator EQEP_CAPTURE_CLK_DIV_1 = 0x00¶: CAPCLK = SYSCLKOUT/1.

enumerator EQEP_CAPTURE_CLK_DIV_2 = 0x10¶: CAPCLK = SYSCLKOUT/2.

enumerator EQEP_CAPTURE_CLK_DIV_4 = 0x20¶: CAPCLK = SYSCLKOUT/4.

enumerator EQEP_CAPTURE_CLK_DIV_8 = 0x30¶: CAPCLK = SYSCLKOUT/8.

enumerator EQEP_CAPTURE_CLK_DIV_16 = 0x40¶: CAPCLK = SYSCLKOUT/16.

enumerator EQEP_CAPTURE_CLK_DIV_32 = 0x50¶: CAPCLK = SYSCLKOUT/32.

enumerator EQEP_CAPTURE_CLK_DIV_64 = 0x60¶: CAPCLK = SYSCLKOUT/64.

enumerator EQEP_CAPTURE_CLK_DIV_128 = 0x70¶: CAPCLK = SYSCLKOUT/128.

enum EQEP_UPEVNTPrescale¶

Values that can be passed to EQEP_setCaptureConfig() as the evntPrescale parameter. UPEVNT is the unit position event frequency.

Values:

enumerator EQEP_UNIT_POS_EVNT_DIV_1¶: UPEVNT = QCLK/1.

enumerator EQEP_UNIT_POS_EVNT_DIV_2¶: UPEVNT = QCLK/2.

enumerator EQEP_UNIT_POS_EVNT_DIV_4¶: UPEVNT = QCLK/4.

enumerator EQEP_UNIT_POS_EVNT_DIV_8¶: UPEVNT = QCLK/8.

enumerator EQEP_UNIT_POS_EVNT_DIV_16¶: UPEVNT = QCLK/16.

enumerator EQEP_UNIT_POS_EVNT_DIV_32¶: UPEVNT = QCLK/32.

enumerator EQEP_UNIT_POS_EVNT_DIV_64¶: UPEVNT = QCLK/64.

enumerator EQEP_UNIT_POS_EVNT_DIV_128¶: UPEVNT = QCLK/128.

enumerator EQEP_UNIT_POS_EVNT_DIV_256¶: UPEVNT = QCLK/256.

enumerator EQEP_UNIT_POS_EVNT_DIV_512¶: UPEVNT = QCLK/512.

enumerator EQEP_UNIT_POS_EVNT_DIV_1024¶: UPEVNT = QCLK/1024.

enumerator EQEP_UNIT_POS_EVNT_DIV_2048¶: UPEVNT = QCLK/2048.

enum EQEP_StrobeSource¶

Values that can be passed to EQEP_setStrobeSource() as the strobeSrc parameter.

Values:

enumerator EQEP_STROBE_FROM_GPIO = 0¶: Strobe signal comes from GPIO.

enumerator EQEP_STROBE_OR_ADCSOCA = 2¶: Strobe signal is OR’d with ADCSOCA.

enumerator EQEP_STROBE_OR_ADCSOCB = 3¶: Strobe signal is OR’d with ADCSOCB.

enum EQEP_QMAMode¶

Values that can be passed to EQEP_setQMAModuleMode() as the qmaMode parameter.

Values:

enumerator EQEP_QMA_MODE_BYPASS¶: QMA module is bypassed.

enumerator EQEP_QMA_MODE_1¶: QMA mode-1 operation is selected.

enumerator EQEP_QMA_MODE_2¶: QMA mode-2 operation is selected.

enum EQEP_Source¶

Possible values of sources for QEPA,QEPB and Index signal which are passed as a structure to EQEP_selectSource() as sourceConfig

Values:

enumerator EQEP_SOURCE_DEVICE_PIN = 0x0000U¶: signal comes from Device Pin

enumerator EQEP_SOURCE_CMPSS1 = 0x0001U¶: signal comes from CMPSS1

enumerator EQEP_SOURCE_CMPSS2 = 0x0002U¶: signal comes from CMPSS2

enumerator EQEP_SOURCE_CMPSS3 = 0x0003U¶: signal comes from CMPSS3

enumerator EQEP_SOURCE_CMPSS4 = 0x0004U¶: signal comes from CMPSS4

enumerator EQEP_SOURCE_CMPSS5 = 0x0005U¶: signal comes from CMPSS5

enumerator EQEP_SOURCE_CMPSS6 = 0x0006U¶: signal comes from CMPSS6

enumerator EQEP_SOURCE_CMPSS7 = 0x0007U¶: signal comes from CMPSS7

enumerator EQEP_SOURCE_CMPSS8 = 0x0008U¶: signal comes from CMPSS8

enumerator EQEP_SOURCE_PWMXBAR1 = 0x0009U¶: signal comes from PWMXBAR1

enumerator EQEP_SOURCE_PWMXBAR2 = 0x000AU¶: signal comes from PWMXBAR2

enumerator EQEP_SOURCE_PWMXBAR3 = 0x000BU¶: signal comes from PWMXBAR3

enumerator EQEP_SOURCE_PWMXBAR4 = 0x000CU¶: signal comes from PWMXBAR4

enumerator EQEP_SOURCE_PWMXBAR5 = 0x000DU¶: signal comes from PWMXBAR5

enumerator EQEP_SOURCE_PWMXBAR6 = 0x000EU¶: signal comes from PWMXBAR6

enumerator EQEP_SOURCE_PWMXBAR7 = 0x000FU¶: signal comes from PWMXBAR7

enum EQEP_EmulationMode¶

Values that can be passed to EQEP_setEmulationMode() as the emuMode parameter.

Values:

enumerator EQEP_EMULATIONMODE_STOPIMMEDIATELY¶: Counters stop immediately.

enumerator EQEP_EMULATIONMODE_STOPATROLLOVER¶: Counters stop at period rollover.

enumerator EQEP_EMULATIONMODE_RUNFREE¶: Counter unaffected by suspend.

Functions

void EQEP_enableModule(uint32_t base)¶

Enables the eQEP module.

This function enables operation of the enhanced quadrature encoder pulse (eQEP) module. The module must be configured before it is enabled.

Parameters

base: is the base address of the eQEP module.

See: EQEP_setConfig()
Return: None.

void EQEP_disableModule(uint32_t base)¶

Disables the eQEP module.

This function disables operation of the eQEP module.

Parameters

base: is the base address of the enhanced quadrature encoder pulse (eQEP) module

Return: None.

void EQEP_setDecoderConfig(uint32_t base, uint16_t config)¶

Configures eQEP module’s quadrature decoder unit.

This function configures the operation of the eQEP module’s quadrature decoder unit. The

config parameter provides the configuration of the decoder and is the logical OR of several values:

Parameters

base: is the base address of the eQEP module.
config: is the configuration for the eQEP module decoder unit.

EQEP_CONFIG_2X_RESOLUTION or EQEP_CONFIG_1X_RESOLUTION specify if both rising and falling edges should be counted or just rising edges.
EQEP_CONFIG_QUADRATURE, EQEP_CONFIG_CLOCK_DIR, EQEP_CONFIG_UP_COUNT, or EQEP_CONFIG_DOWN_COUNT specify if quadrature signals are being provided on QEPA and QEPB, if a direction signal and a clock are being provided, or if the direction should be hard-wired for a single direction with QEPA used for input.
EQEP_CONFIG_NO_SWAP or EQEP_CONFIG_SWAP to specify if the signals provided on QEPA and QEPB should be swapped before being processed.

Return: None.

void EQEP_setPositionCounterConfig(uint32_t base, EQEP_PositionResetMode mode, uint32_t maxPosition)¶

Configures eQEP module position counter unit.

This function configures the operation of the eQEP module position counter. The

mode parameter determines the event on which the position counter gets reset. It should be passed one of the following values: EQEP_POSITION_RESET_IDX, EQEP_POSITION_RESET_MAX_POS, EQEP_POSITION_RESET_1ST_IDX, or EQEP_POSITION_RESET_UNIT_TIME_OUT.

Parameters

base: is the base address of the eQEP module.
mode: is the configuration for the eQEP module position counter.
maxPosition: specifies the maximum position value.

maxPosition is the maximum value of the position counter and is the value used to reset the position capture when moving in the reverse (negative) direction.

Return: None.

uint32_t EQEP_getPosition(uint32_t base)¶

Gets the current encoder position.

This function returns the current position of the encoder. Depending upon the configuration of the encoder, and the incident of an index pulse, this value may or may not contain the expected data (that is, if in reset on index mode, if an index pulse has not been encountered, the position counter is not yet aligned with the index pulse).

Parameters

base: is the base address of the eQEP module.

Return: The current position of the encoder.

void EQEP_setPosition(uint32_t base, uint32_t position)¶

Sets the current encoder position.

This function sets the current position of the encoder; the encoder position is then measured relative to this value.

Parameters

base: is the base address of the eQEP module.
position: is the new position for the encoder.

Return: None.

int16_t EQEP_getDirection(uint32_t base)¶

Gets the current direction of rotation.

This function returns the current direction of rotation. In this case, current means the most recently detected direction of the encoder; it may not be presently moving but this is the direction it last moved before it stopped.

Parameters

base: is the base address of the eQEP module.

Return: Returns 1 if moving in the forward direction or -1 if moving in the reverse direction.

void EQEP_enableInterrupt(uint32_t base, uint16_t intFlags)¶

Enables individual eQEP module interrupt sources.

This function enables eQEP module interrupt sources. The

intFlags parameter can be any of the following values OR’d together:

EQEP_INT_POS_CNT_ERROR - Position counter error
EQEP_INT_PHASE_ERROR - Quadrature phase error
EQEP_INT_DIR_CHANGE - Quadrature direction change
EQEP_INT_WATCHDOG - Watchdog time-out
EQEP_INT_UNDERFLOW - Position counter underflow
EQEP_INT_OVERFLOW - Position counter overflow
EQEP_INT_POS_COMP_READY - Position-compare ready
EQEP_INT_POS_COMP_MATCH - Position-compare match
EQEP_INT_STROBE_EVNT_LATCH - Strobe event latch
EQEP_INT_INDEX_EVNT_LATCH - Index event latch
EQEP_INT_UNIT_TIME_OUT - Unit time-out

Parameters

base: is the base address of the eQEP module.
intFlags: is a bit mask of the interrupt sources to be enabled.

Return: None.

void EQEP_disableInterrupt(uint32_t base, uint16_t intFlags)¶

Disables individual eQEP module interrupt sources.

This function disables eQEP module interrupt sources. The

intFlags parameter can be any of the following values OR’d together:

EQEP_INT_POS_CNT_ERROR - Position counter error
EQEP_INT_PHASE_ERROR - Quadrature phase error
EQEP_INT_DIR_CHANGE - Quadrature direction change
EQEP_INT_WATCHDOG - Watchdog time-out
EQEP_INT_UNDERFLOW - Position counter underflow
EQEP_INT_OVERFLOW - Position counter overflow
EQEP_INT_POS_COMP_READY - Position-compare ready
EQEP_INT_POS_COMP_MATCH - Position-compare match
EQEP_INT_STROBE_EVNT_LATCH - Strobe event latch
EQEP_INT_INDEX_EVNT_LATCH - Index event latch
EQEP_INT_UNIT_TIME_OUT - Unit time-out

Parameters

base: is the base address of the eQEP module.
intFlags: is a bit mask of the interrupt sources to be disabled.

Return: None.

uint16_t EQEP_getInterruptStatus(uint32_t base)¶

Gets the current interrupt status.

This function returns the interrupt status for the eQEP module module.

Parameters

base: is the base address of the eQEP module.

Return

Returns the current interrupt status, enumerated as a bit field of the following values:

EQEP_INT_GLOBAL - Global interrupt flag
EQEP_INT_POS_CNT_ERROR - Position counter error
EQEP_INT_PHASE_ERROR - Quadrature phase error
EQEP_INT_DIR_CHANGE - Quadrature direction change
EQEP_INT_WATCHDOG - Watchdog time-out
EQEP_INT_UNDERFLOW - Position counter underflow
EQEP_INT_OVERFLOW - Position counter overflow
EQEP_INT_POS_COMP_READY - Position-compare ready
EQEP_INT_POS_COMP_MATCH - Position-compare match
EQEP_INT_STROBE_EVNT_LATCH - Strobe event latch
EQEP_INT_INDEX_EVNT_LATCH - Index event latch
EQEP_INT_UNIT_TIME_OUT - Unit time-out

void EQEP_clearInterruptStatus(uint32_t base, uint16_t intFlags)¶

Clears eQEP module interrupt sources.

This function clears eQEP module interrupt flags. The

intFlags parameter can be any of the following values OR’d together:

EQEP_INT_GLOBAL - Global interrupt flag
EQEP_INT_POS_CNT_ERROR - Position counter error
EQEP_INT_PHASE_ERROR - Quadrature phase error
EQEP_INT_DIR_CHANGE - Quadrature direction change
EQEP_INT_WATCHDOG - Watchdog time-out
EQEP_INT_UNDERFLOW - Position counter underflow
EQEP_INT_OVERFLOW - Position counter overflow
EQEP_INT_POS_COMP_READY - Position-compare ready
EQEP_INT_POS_COMP_MATCH - Position-compare match
EQEP_INT_STROBE_EVNT_LATCH - Strobe event latch
EQEP_INT_INDEX_EVNT_LATCH - Index event latch
EQEP_INT_UNIT_TIME_OUT - Unit time-out

Parameters

base: is the base address of the eQEP module.
intFlags: is a bit mask of the interrupt sources to be cleared.

Note that the EQEP_INT_GLOBAL value is the global interrupt flag. In order to get any further eQEP interrupts, this flag must be cleared.

Return: None.

void EQEP_forceInterrupt(uint32_t base, uint16_t intFlags)¶

Forces individual eQEP module interrupts.

This function forces eQEP module interrupt flags. The

intFlags parameter can be any of the following values OR’d together:

EQEP_INT_POS_CNT_ERROR
EQEP_INT_PHASE_ERROR
EQEP_INT_DIR_CHANGE
EQEP_INT_WATCHDOG
EQEP_INT_UNDERFLOW
EQEP_INT_OVERFLOW
EQEP_INT_POS_COMP_READY
EQEP_INT_POS_COMP_MATCH
EQEP_INT_STROBE_EVNT_LATCH
EQEP_INT_INDEX_EVNT_LATCH
EQEP_INT_UNIT_TIME_OUT

Parameters

base: is the base address of the eQEP module.
intFlags: is a bit mask of the interrupt sources to be forced.

Return: None.

bool EQEP_getError(uint32_t base)¶

Gets the encoder error indicator.

This function returns the error indicator for the eQEP module. It is an error for both of the signals of the quadrature input to change at the same time.

Parameters

base: is the base address of the eQEP module.

Return: Returns true if an error has occurred and false otherwise.

uint16_t EQEP_getStatus(uint32_t base)¶

Returns content of the eQEP module status register

This function returns the contents of the status register. The value it returns is an OR of the following values:

Parameters

base: is the base address of the eQEP module.

EQEP_STS_UNIT_POS_EVNT - Unit position event detected
EQEP_STS_DIR_ON_1ST_IDX - If set, clockwise rotation (forward movement) occurred on the first index event
EQEP_STS_DIR_FLAG - If set, movement is clockwise rotation
EQEP_STS_DIR_LATCH - If set, clockwise rotation occurred on last index event marker
EQEP_STS_CAP_OVRFLW_ERROR - Overflow occurred in eQEP capture timer
EQEP_STS_CAP_DIR_ERROR - Direction change occurred between position capture events
EQEP_STS_1ST_IDX_FLAG - Set by the occurrence of the first index pulse
EQEP_STS_POS_CNT_ERROR - Position counter error occurred

Return: Returns the value of the QEP status register.

void EQEP_clearStatus(uint32_t base, uint16_t statusFlags)¶

Clears selected fields of the eQEP module status register

This function clears the status register fields indicated by

statusFlags. The statusFlags parameter is the logical OR of any of the following:

Parameters

base: is the base address of the eQEP module.
statusFlags: is the bit mask of the status flags to be cleared.

EQEP_STS_UNIT_POS_EVNT - Unit position event detected
EQEP_STS_CAP_OVRFLW_ERROR - Overflow occurred in eQEP capture timer
EQEP_STS_CAP_DIR_ERROR - Direction change occurred between position capture events
EQEP_STS_1ST_IDX_FLAG - Set by the occurrence of the first index pulse

Note: Only the above status fields can be cleared. All others are read-only, non-sticky fields.
Return: None.

void EQEP_setCaptureConfig(uint32_t base, EQEP_CAPCLKPrescale capPrescale, EQEP_UPEVNTPrescale evntPrescale)¶

Configures eQEP module edge-capture unit.

This function configures the operation of the eQEP module edge-capture unit. The

capPrescale parameter provides the configuration of the eQEP capture timer clock rate. It determines by which power of 2 between 1 and 128 inclusive SYSCLKOUT is divided. The macros for this parameter are in the format of EQEP_CAPTURE_CLK_DIV_X, where X is the divide value. For example, EQEP_CAPTURE_CLK_DIV_32 will give a capture timer clock frequency that is SYSCLKOUT/32.

Parameters

base: is the base address of the eQEP module.
capPrescale: is the prescaler setting of the eQEP capture timer clk.
evntPrescale: is the prescaler setting of the unit position event frequency.

The evntPrescale parameter determines how frequently a unit position event occurs. The macro that can be passed this parameter is in the format EQEP_UNIT_POS_EVNT_DIV_X, where X is the number of quadrature clock periods between unit position events. For example, EQEP_UNIT_POS_EVNT_DIV_16 will result in a unit position event frequency of QCLK/16.

Return: None.

void EQEP_enableCapture(uint32_t base)¶

Enables the eQEP module edge-capture unit.

This function enables operation of the eQEP module’s edge-capture unit.

Parameters

base: is the base address of the eQEP module.

Return: None.

void EQEP_disableCapture(uint32_t base)¶

Disables the eQEP module edge-capture unit.

This function disables operation of the eQEP module’s edge-capture unit.

Parameters

base: is the base address of the eQEP module.

Return: None.

uint16_t EQEP_getCapturePeriod(uint32_t base)¶

Gets the encoder capture period.

This function returns the period count value between the last successive eQEP position events.

Parameters

base: is the base address of the eQEP module.

Return: The period count value between the last successive position events.

uint16_t EQEP_getCaptureTimer(uint32_t base)¶

Gets the encoder capture timer value.

This function returns the time base for the edge capture unit.

Parameters

base: is the base address of the eQEP module.

Return: The capture timer value.

void EQEP_enableCompare(uint32_t base)¶

Enables the eQEP module position-compare unit.

This function enables operation of the eQEP module’s position-compare unit.

Parameters

base: is the base address of the eQEP module.

Return: None.

void EQEP_disableCompare(uint32_t base)¶

Disables the eQEP module position-compare unit.

This function disables operation of the eQEP module’s position-compare unit.

Parameters

base: is the base address of the eQEP module.

Return: None.

void EQEP_setComparePulseWidth(uint32_t base, uint16_t cycles)¶

Configures the position-compare unit’s sync output pulse width.

This function configures the width of the sync output pulse. The width of the pulse will be

cycles * 4 * the width of a SYSCLKOUT cycle. The maximum width is 4096 * 4 * SYSCLKOUT cycles.

Parameters

base: is the base address of the eQEP module.
cycles: is the width of the pulse that can be generated on a position-compare event. It is in units of 4 SYSCLKOUT cycles.

Return: None.

void EQEP_loadUnitTimer(uint32_t base, uint32_t period)¶

Loads the eQEP module unit timer period as number of SYSCLK cycles.

This function sets the unit time-out interrupt when it matches the value specified by

period The unit timer is clocked by SYSCLKOUT

Parameters

base: is the base address of the eQEP module.
period: is period value at which a unit time-out interrupt is set.

Return: None.

void EQEP_enableUnitTimer(uint32_t base, uint32_t period)¶

Enables the eQEP module unit timer.

This function enables operation of the eQEP module’s peripheral unit timer. The unit timer is clocked by SYSCLKOUT and will set the unit time-out interrupt when it matches the value specified by

period.

Parameters

base: is the base address of the eQEP module.
period: is period value at which a unit time-out interrupt is set.

Return: None.

void EQEP_disableUnitTimer(uint32_t base)¶

Disables the eQEP module unit timer.

This function disables operation of the eQEP module’s peripheral unit timer.

Parameters

base: is the base address of the eQEP module.

Return: None.

void EQEP_enableWatchdog(uint32_t base, uint16_t period)¶

Enables the eQEP module watchdog timer.

This function enables operation of the eQEP module’s peripheral watchdog timer.

Parameters

base: is the base address of the eQEP module.
period: is watchdog period value at which a time-out will occur if no quadrature-clock event is detected.

Note: When selecting period, note that the watchdog timer is clocked from SYSCLKOUT/64.
Return: None.

void EQEP_disableWatchdog(uint32_t base)¶

Disables the eQEP module watchdog timer.

This function disables operation of the eQEP module’s peripheral watchdog timer.

Parameters

base: is the base address of the eQEP module.

Return: None.

void EQEP_setWatchdogTimerValue(uint32_t base, uint16_t value)¶

Sets the eQEP module watchdog timer value.

This function sets the eQEP module’s watchdog timer value.

Parameters

base: is the base address of the eQEP module.
value: is the value to be written to the watchdog timer.

Return: None.

uint16_t EQEP_getWatchdogTimerValue(uint32_t base)¶

Gets the eQEP module watchdog timer value.

Return

Returns the current watchdog timer value.

Parameters

base: is the base address of the eQEP module.

void EQEP_setPositionInitMode(uint32_t base, uint16_t initMode)¶

Configures the mode in which the position counter is initialized.

This function configures the events on which the position count can be initialized. The

initMode parameter provides the mode as either EQEP_INIT_DO_NOTHING (no action configured) or one of the following strobe events, index events, or a logical OR of both a strobe event and an index event.

Parameters

base: is the base address of the eQEP module.
initMode: is the configuration for initializing the position count. See below for a description of this parameter.

EQEP_INIT_RISING_STROBE or EQEP_INIT_EDGE_DIR_STROBE specify which strobe event will initialize the position counter.
EQEP_INIT_RISING_INDEX or EQEP_INIT_FALLING_INDEX specify which index event will initialize the position counter.

Use EQEP_setSWPositionInit() to cause a software initialization and EQEP_setInitialPosition() to set the value that gets loaded into the position counter upon initialization.

Return: None.

void EQEP_setSWPositionInit(uint32_t base, bool initialize)¶

Sets the software initialization of the encoder position counter.

This function does a software initialization of the position counter when the

initialize parameter is true. When false, the QEPCTL[SWI] bit is cleared and no action is taken.

Parameters

base: is the base address of the eQEP module.
initialize: is a flag to specify if software initialization of the position counter is enabled.

The init value to be loaded into the position counter can be set with EQEP_setInitialPosition(). Additional initialization causes can be configured with EQEP_setPositionInitMode().

Return: None.

void EQEP_setInitialPosition(uint32_t base, uint32_t position)¶

Sets the init value for the encoder position counter.

This function sets the init value for position of the encoder. See

EQEP_setPositionInitMode() to set the initialization cause or EQEP_setSWPositionInit() to cause a software initialization.

Parameters

base: is the base address of the eQEP module.
position: is the value to be written to the position counter upon. initialization.

Return: None.

void EQEP_setLatchMode(uint32_t base, uint32_t latchMode)¶

Configures the quadrature modes in which the position count can be latched.

This function configures the events on which the position count and several other registers can be latched. The

latchMode parameter provides the mode as the logical OR of several values.

Parameters

base: is the base address of the eQEP module.
latchMode: is the configuration for latching of the position count and several other registers. See below for a description of this parameter.

EQEP_LATCH_CNT_READ_BY_CPU or EQEP_LATCH_UNIT_TIME_OUT specify the event that latches the position counter. This latch register can be read using EQEP_getPositionLatch(). The capture timer and capture period are also latched based on this setting, and can be read using EQEP_getCaptureTimerLatch() and EQEP_getCapturePeriodLatch().
EQEP_LATCH_RISING_STROBE or EQEP_LATCH_EDGE_DIR_STROBE specify which strobe event will latch the position counter into the strobe position latch register. This register can be read with EQEP_getStrobePositionLatch().
EQEP_LATCH_RISING_INDEX, EQEP_LATCH_FALLING_INDEX, or EQEP_LATCH_SW_INDEX_MARKER specify which index event will latch the position counter into the index position latch register. This register can be read with EQEP_getIndexPositionLatch().

Return: None.

uint32_t EQEP_getIndexPositionLatch(uint32_t base)¶

Gets the encoder position that was latched on an index event.

This function returns the value in the index position latch register. The position counter is latched into this register on either a rising index edge, a falling index edge, or a software index marker. This is configured using

EQEP_setLatchMode().

Parameters

base: is the base address of the eQEP module.

Return: The position count latched on an index event.

uint32_t EQEP_getStrobePositionLatch(uint32_t base)¶

Gets the encoder position that was latched on a strobe event.

This function returns the value in the strobe position latch register. The position counter can be configured to be latched into this register on rising strobe edges only or on rising strobe edges while moving clockwise and falling strobe edges while moving counter-clockwise. This is configured using

EQEP_setLatchMode().

Parameters

base: is the base address of the eQEP module.

Return: The position count latched on a strobe event.

uint32_t EQEP_getPositionLatch(uint32_t base)¶

Gets the encoder position that was latched on a unit time-out event.

This function returns the value in the position latch register. The position counter is latched into this register either on a unit time-out event.

Parameters

base: is the base address of the eQEP module.

Return: The position count latch register value.

uint16_t EQEP_getCaptureTimerLatch(uint32_t base)¶

Gets the encoder capture timer latch.

This function returns the value in the capture timer latch register. The capture timer value is latched into this register either on a unit time-out event or upon the CPU reading the eQEP position counter. This is configured using

EQEP_setLatchMode().

Parameters

base: is the base address of the eQEP module.

Return: The edge-capture timer latch value.

uint16_t EQEP_getCapturePeriodLatch(uint32_t base)¶

Gets the encoder capture period latch.

This function returns the value in the capture period latch register. The capture period value is latched into this register either on a unit time-out event or upon the CPU reading the eQEP position counter. This is configured using

EQEP_setLatchMode().

Parameters

base: is the base address of the eQEP module.

Return: The edge-capture period latch value.

void EQEP_setQMAModuleMode(uint32_t base, EQEP_QMAMode qmaMode)¶

Set the quadrature mode adapter (QMA) module mode

This function sets the quadrature mode adapter module mode. The possible modes are passed to the function through the

qmaMode parameter which can take the values EQEP_QMA_MODE_BYPASS, EQEP_QMA_MODE_1, or EQEP_QMA_MODE_2.

Parameters

base: is the base address of the eQEP module.
qmaMode: is the mode in which the QMA module will operate.

To use the QMA module, you must first put the eQEP module into direction-count mode (EQEP_CONFIG_CLOCK_DIR) using EQEP_setConfig().

Return: None.

void EQEP_setStrobeSource(uint32_t base, EQEP_StrobeSource strobeSrc)¶

Set the strobe input source of the eQEP module.

This function sets the source of the eQEP module’s strobe signal. The possible values of the

strobeSrc parameter are

EQEP_STROBE_FROM_GPIO - The strobe is used as-is after passing through the polarity select logic.
EQEP_STROBE_OR_ADCSOCA - The strobe is OR’d with the ADCSOCA signal after passing through the polarity select logic.
EQEP_STROBE_OR_ADCSOCB - The strobe is OR’d with the ADCSOCB signal after passing through the polarity select logic.

Parameters

base: is the base address of the eQEP module.
strobeSrc: is the source of the strobe signal.

Return: None.

void EQEP_enableDirectionChangeDuringIndex(uint32_t base)¶

Enables the index direction enhancement mode of the eQEP module

This function enables the enhancement mode for direction change during Index event

Parameters

base: is the base address of the eQEP module.

Return: None.

void EQEP_disableDirectionChangeDuringIndex(uint32_t base)¶

Disables the index direction enhancement mode of the eQEP module

This function disables the enhancement mode for direction change during Index event

Parameters

base: is the base address of the eQEP module.

Return: None.

void EQEP_selectSource(uint32_t base, EQEP_SourceSelect sourceConfig)¶

Selects the source for eQEPA/B/I signals

This function configures the sources for QEPA,QEPB and Index of eQEP module

Parameters

base: is the base address of the enhanced quadrature encoder pulse (eQEP) module
sourceConfig: is the structure that contains source configuration

Return: None.

void EQEP_setEmulationMode(uint32_t base, EQEP_EmulationMode emuMode)¶

Set the emulation mode of the eQEP module.

This function sets the eQEP module’s emulation mode. This mode determines how the timers are affected by an emulation suspend. Valid values for the

emuMode parameter are the following:

Parameters

base: is the base address of the eQEP module.
emuMode: is the mode operation upon an emulation suspend.

EQEP_EMULATIONMODE_STOPIMMEDIATELY - The position counter, watchdog counter, unit timer, and capture timer all stop immediately.
EQEP_EMULATIONMODE_STOPATROLLOVER - The position counter, watchdog counter, unit timer all count until period rollover. The capture timer counts until the next unit period event.
EQEP_EMULATIONMODE_RUNFREE - The position counter, watchdog counter, unit timer, and capture timer are all unaffected by an emulation suspend.

Return: None.

void EQEP_setCompareConfig(uint32_t base, uint16_t config, uint32_t compareValue, uint16_t cycles)¶

Configures eQEP module position-compare unit.

This function configures the operation of the eQEP module position-compare unit. The

config parameter provides the configuration of the position-compare unit and is the logical OR of several values:

Parameters

base: is the base address of the eQEP module.
config: is the configuration for the eQEP module position-compare unit. See below for a description of this parameter.
compareValue: is the value to which the position count value is compared for a position-compare event.
cycles: is the width of the pulse that can be generated on a position-compare event. It is in units of 4 SYSCLKOUT cycles.

EQEP_COMPARE_NO_SYNC_OUT, EQEP_COMPARE_IDX_SYNC_OUT, or EQEP_COMPARE_STROBE_SYNC_OUT specify if there is a sync output pulse and which pin should be used.
EQEP_COMPARE_NO_SHADOW, EQEP_COMPARE_LOAD_ON_ZERO, or EQEP_COMPARE_LOAD_ON_MATCH specify if a shadow is enabled and when should the load should occurQPOSCNT = 0 or QPOSCNT = QPOSCOMP.

The cycles is used to select the width of the sync output pulse. The width of the resulting pulse will be cycles * 4 * the width of a SYSCLKOUT cycle. The maximum width is 4096 * 4 * SYSCLKOUT cycles.

Note: You can set the sync pulse width independently using the EQEP_setComparePulseWidth() function.
Return: None.

void EQEP_setInputPolarity(uint32_t base, bool invertQEPA, bool invertQEPB, bool invertIndex, bool invertStrobe)¶

Sets the polarity of the eQEP module’s input signals.

This function configures the polarity of the inputs to the eQEP module. To negate the polarity of any of the input signals, pass

true into its corresponding parameter in this function. Pass false to leave it as-is.

Parameters

base: is the base address of the eQEP module.
invertQEPA: is the flag to negate the QEPA input.
invertQEPB: is the flag to negate the QEPA input.
invertIndex: is the flag to negate the index input.
invertStrobe: is the flag to negate the strobe input.

Return: None.

struct EQEP_SourceSelect¶: #include <eqep.h>
Structure to be passed to EQEP_selectSource() as sourceConfig.

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