The MCUXpresso SDK provides a peripheral driver for the Quadrature Encoder/Decoder (ENC) module of MCUXpresso SDK devices.
This section describes the programming interface of the ENC Peripheral driver. The ENC driver configures the ENC module and provides a functional interface for the user to build the ENC application.
Function groups
Initialization and De-initialization
This function group initializes default configuration structure for the ENC counter and initializes ENC counter with the normal configuration and de-initialize ENC module. Some APIs are also created to control the features.
Status
This function group get/clear the ENC status.
Interrupts
This function group enable/disable the ENC interrupts.
Value Operation
This function group get the counter/hold value of positions.
Typical use case
Polling Configuration
Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/enc
|
| enum | _enc_interrupt_enable {
kENC_HOMETransitionInterruptEnable = (1U << 0U),
kENC_INDEXPulseInterruptEnable = (1U << 1U),
kENC_WatchdogTimeoutInterruptEnable = (1U << 2U),
kENC_PositionCompareInerruptEnable = (1U << 3U),
kENC_SimultBothPhaseChangeInterruptEnable,
kENC_PositionRollOverInterruptEnable = (1U << 5U),
kENC_PositionRollUnderInterruptEnable = (1U << 6U)
} |
| | Interrupt enable/disable mask. More...
|
| |
| enum | _enc_status_flags {
kENC_HOMETransitionFlag = (1U << 0U),
kENC_INDEXPulseFlag = (1U << 1U),
kENC_WatchdogTimeoutFlag = (1U << 2U),
kENC_PositionCompareFlag = (1U << 3U),
kENC_SimultBothPhaseChangeFlag = (1U << 4U),
kENC_PositionRollOverFlag = (1U << 5U),
kENC_PositionRollUnderFlag = (1U << 6U),
kENC_LastCountDirectionFlag = (1U << 7U)
} |
| | Status flag mask. More...
|
| |
| enum | _enc_signal_status_flags {
kENC_RawHOMEStatusFlag = ENC_IMR_HOME_MASK,
kENC_RawINDEXStatusFlag = ENC_IMR_INDEX_MASK,
kENC_RawPHBStatusFlag = ENC_IMR_PHB_MASK,
kENC_RawPHAEXStatusFlag = ENC_IMR_PHA_MASK,
kENC_FilteredHOMEStatusFlag = ENC_IMR_FHOM_MASK,
kENC_FilteredINDEXStatusFlag = ENC_IMR_FIND_MASK,
kENC_FilteredPHBStatusFlag = ENC_IMR_FPHB_MASK,
kENC_FilteredPHAStatusFlag = ENC_IMR_FPHA_MASK
} |
| | Signal status flag mask. More...
|
| |
| enum | enc_home_trigger_mode_t {
kENC_HOMETriggerDisabled = 0U,
kENC_HOMETriggerOnRisingEdge,
kENC_HOMETriggerOnFallingEdge
} |
| | Define HOME signal's trigger mode. More...
|
| |
| enum | enc_index_trigger_mode_t {
kENC_INDEXTriggerDisabled = 0U,
kENC_INDEXTriggerOnRisingEdge,
kENC_INDEXTriggerOnFallingEdge
} |
| | Define INDEX signal's trigger mode. More...
|
| |
| enum | enc_decoder_work_mode_t {
kENC_DecoderWorkAsNormalMode = 0U,
kENC_DecoderWorkAsSignalPhaseCountMode
} |
| | Define type for decoder work mode. More...
|
| |
| enum | enc_position_match_mode_t {
kENC_POSMATCHOnPositionCounterEqualToComapreValue = 0U,
kENC_POSMATCHOnReadingAnyPositionCounter
} |
| | Define type for the condition of POSMATCH pulses. More...
|
| |
| enum | enc_revolution_count_condition_t {
kENC_RevolutionCountOnINDEXPulse = 0U,
kENC_RevolutionCountOnRollOverModulus
} |
| | Define type for determining how the revolution counter (REV) is incremented/decremented. More...
|
| |
| enum | enc_self_test_direction_t {
kENC_SelfTestDirectionPositive = 0U,
kENC_SelfTestDirectionNegative
} |
| | Define type for direction of self test generated signal. More...
|
| |
| struct enc_self_test_config_t |
The self test module provides a quadrature test signal to the inputs of the quadrature decoder module. This is a factory test feature. It is also useful to customers' software development and testing.
| Enumerator |
|---|
| kENC_HOMETransitionInterruptEnable |
HOME interrupt enable.
|
| kENC_INDEXPulseInterruptEnable |
INDEX pulse interrupt enable.
|
| kENC_WatchdogTimeoutInterruptEnable |
Watchdog timeout interrupt enable.
|
| kENC_PositionCompareInerruptEnable |
Position compare interrupt enable.
|
| kENC_SimultBothPhaseChangeInterruptEnable |
Simultaneous PHASEA and PHASEB change interrupt enable.
|
| kENC_PositionRollOverInterruptEnable |
Roll-over interrupt enable.
|
| kENC_PositionRollUnderInterruptEnable |
Roll-under interrupt enable.
|
These flags indicate the counter's events.
| Enumerator |
|---|
| kENC_HOMETransitionFlag |
HOME signal transition interrupt request.
|
| kENC_INDEXPulseFlag |
INDEX Pulse Interrupt Request.
|
| kENC_WatchdogTimeoutFlag |
Watchdog timeout interrupt request.
|
| kENC_PositionCompareFlag |
Position compare interrupt request.
|
| kENC_SimultBothPhaseChangeFlag |
Simultaneous PHASEA and PHASEB change interrupt request.
|
| kENC_PositionRollOverFlag |
Roll-over interrupt request.
|
| kENC_PositionRollUnderFlag |
Roll-under interrupt request.
|
| kENC_LastCountDirectionFlag |
Last count was in the up direction, or the down direction.
|
These flags indicate the counter's signal.
| Enumerator |
|---|
| kENC_RawHOMEStatusFlag |
Raw HOME input.
|
| kENC_RawINDEXStatusFlag |
Raw INDEX input.
|
| kENC_RawPHBStatusFlag |
Raw PHASEB input.
|
| kENC_RawPHAEXStatusFlag |
Raw PHASEA input.
|
| kENC_FilteredHOMEStatusFlag |
The filtered version of HOME input.
|
| kENC_FilteredINDEXStatusFlag |
The filtered version of INDEX input.
|
| kENC_FilteredPHBStatusFlag |
The filtered version of PHASEB input.
|
| kENC_FilteredPHAStatusFlag |
The filtered version of PHASEA input.
|
The ENC would count the trigger from HOME signal line.
| Enumerator |
|---|
| kENC_HOMETriggerDisabled |
HOME signal's trigger is disabled.
|
| kENC_HOMETriggerOnRisingEdge |
Use positive going edge-to-trigger initialization of position counters.
|
| kENC_HOMETriggerOnFallingEdge |
Use negative going edge-to-trigger initialization of position counters.
|
The ENC would count the trigger from INDEX signal line.
| Enumerator |
|---|
| kENC_INDEXTriggerDisabled |
INDEX signal's trigger is disabled.
|
| kENC_INDEXTriggerOnRisingEdge |
Use positive going edge-to-trigger initialization of position counters.
|
| kENC_INDEXTriggerOnFallingEdge |
Use negative going edge-to-trigger initialization of position counters.
|
The normal work mode uses the standard quadrature decoder with PHASEA and PHASEB. When in signal phase count mode, a positive transition of the PHASEA input generates a count signal while the PHASEB input and the reverse direction control the counter direction. If the reverse direction is not enabled, PHASEB = 0 means counting up and PHASEB = 1 means counting down. Otherwise, the direction is reversed.
| Enumerator |
|---|
| kENC_DecoderWorkAsNormalMode |
Use standard quadrature decoder with PHASEA and PHASEB.
|
| kENC_DecoderWorkAsSignalPhaseCountMode |
PHASEA input generates a count signal while PHASEB input control the direction.
|
| Enumerator |
|---|
| kENC_POSMATCHOnPositionCounterEqualToComapreValue |
POSMATCH pulses when a match occurs between the position counters (POS) and the compare value (COMP).
|
| kENC_POSMATCHOnReadingAnyPositionCounter |
POSMATCH pulses when any position counter register is read.
|
| Enumerator |
|---|
| kENC_RevolutionCountOnINDEXPulse |
Use INDEX pulse to increment/decrement revolution counter.
|
| kENC_RevolutionCountOnRollOverModulus |
Use modulus counting roll-over/under to increment/decrement revolution counter.
|
| Enumerator |
|---|
| kENC_SelfTestDirectionPositive |
Self test generates the signal in positive direction.
|
| kENC_SelfTestDirectionNegative |
Self test generates the signal in negative direction.
|
| void ENC_Init |
( |
ENC_Type * |
base, |
|
|
const enc_config_t * |
config |
|
) |
| |
This function is to make the initialization for the ENC module. It should be called firstly before any operation to the ENC with the operations like:
- Enable the clock for ENC module.
- Configure the ENC's working attributes.
- Parameters
-
| base | ENC peripheral base address. |
| config | Pointer to configuration structure. See to "enc_config_t". |
| void ENC_Deinit |
( |
ENC_Type * |
base | ) |
|
This function is to make the de-initialization for the ENC module. It could be called when ENC is no longer used with the operations like:
- Disable the clock for ENC module.
- Parameters
-
| base | ENC peripheral base address. |
This function initializes the ENC configuration structure with an available settings, the default value are:
* config->enableReverseDirection = false;
* config->enableTRIGGERClearPositionCounter = false;
* config->enableTRIGGERClearHoldPositionCounter = false;
* config->enableWatchdog = false;
* config->watchdogTimeoutValue = 0U;
* config->filterCount = 0U;
* config->filterSamplePeriod = 0U;
* config->positionCompareValue = 0xFFFFFFFFU;
* config->enableModuloCountMode = false;
* config->positionModulusValue = 0U;
* config->positionInitialValue = 0U;
*
- Parameters
-
| config | Pointer to a variable of configuration structure. See to "enc_config_t". |
| void ENC_DoSoftwareLoadInitialPositionValue |
( |
ENC_Type * |
base | ) |
|
This function is to transfer the initial position value (UINIT and LINIT) contents to position counter (UPOS and LPOS), so that to provide the consistent operation the position counter registers.
- Parameters
-
| base | ENC peripheral base address. |
This function is to enable and configuration the self test function. It controls and sets the frequency of a quadrature signal generator. It provides a quadrature test signal to the inputs of the quadrature decoder module. It is a factory test feature; however, it may be useful to customers' software development and testing.
- Parameters
-
| base | ENC peripheral base address. |
| config | Pointer to configuration structure. See to "enc_self_test_config_t". Pass "NULL" to disable. |
| void ENC_EnableWatchdog |
( |
ENC_Type * |
base, |
|
|
bool |
enable |
|
) |
| |
- Parameters
-
| base | ENC peripheral base address |
| enable | Enables or disables the watchdog |
| void ENC_SetInitialPositionValue |
( |
ENC_Type * |
base, |
|
|
uint32_t |
value |
|
) |
| |
- Parameters
-
| base | ENC peripheral base address |
| value | Positive initial value |
| uint32_t ENC_GetStatusFlags |
( |
ENC_Type * |
base | ) |
|
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- Mask value of status flags. For available mask, see to "_enc_status_flags".
| void ENC_ClearStatusFlags |
( |
ENC_Type * |
base, |
|
|
uint32_t |
mask |
|
) |
| |
- Parameters
-
| base | ENC peripheral base address. |
| mask | Mask value of status flags to be cleared. For available mask, see to "_enc_status_flags". |
| static uint16_t ENC_GetSignalStatusFlags |
( |
ENC_Type * |
base | ) |
|
|
inlinestatic |
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- Mask value of signals' real-time status. For available mask, see to "_enc_signal_status_flags"
| void ENC_EnableInterrupts |
( |
ENC_Type * |
base, |
|
|
uint32_t |
mask |
|
) |
| |
- Parameters
-
| base | ENC peripheral base address. |
| mask | Mask value of interrupts to be enabled. For available mask, see to "_enc_interrupt_enable". |
| void ENC_DisableInterrupts |
( |
ENC_Type * |
base, |
|
|
uint32_t |
mask |
|
) |
| |
- Parameters
-
| base | ENC peripheral base address. |
| mask | Mask value of interrupts to be disabled. For available mask, see to "_enc_interrupt_enable". |
| uint32_t ENC_GetEnabledInterrupts |
( |
ENC_Type * |
base | ) |
|
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- Mask value of enabled interrupts.
| uint32_t ENC_GetPositionValue |
( |
ENC_Type * |
base | ) |
|
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- Current position counter's value.
| uint32_t ENC_GetHoldPositionValue |
( |
ENC_Type * |
base | ) |
|
When any of the counter registers is read, the contents of each counter register is written to the corresponding hold register. Taking a snapshot of the counters' values provides a consistent view of a system position and a velocity to be attained.
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- Hold position counter's value.
| static uint16_t ENC_GetPositionDifferenceValue |
( |
ENC_Type * |
base | ) |
|
|
inlinestatic |
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- The position difference counter's value.
| static uint16_t ENC_GetHoldPositionDifferenceValue |
( |
ENC_Type * |
base | ) |
|
|
inlinestatic |
When any of the counter registers is read, the contents of each counter register is written to the corresponding hold register. Taking a snapshot of the counters' values provides a consistent view of a system position and a velocity to be attained.
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- Hold position difference counter's value.
| static uint16_t ENC_GetRevolutionValue |
( |
ENC_Type * |
base | ) |
|
|
inlinestatic |
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- The position revolution counter's value.
| static uint16_t ENC_GetHoldRevolutionValue |
( |
ENC_Type * |
base | ) |
|
|
inlinestatic |
When any of the counter registers is read, the contents of each counter register is written to the corresponding hold register. Taking a snapshot of the counters' values provides a consistent view of a system position and a velocity to be attained.
- Parameters
-
| base | ENC peripheral base address. |
- Returns
- Hold position revolution counter's value.
| bool enc_config_t::enableReverseDirection |
| bool enc_config_t::enableTRIGGERClearPositionCounter |
| bool enc_config_t::enableWatchdog |
| uint16_t enc_config_t::watchdogTimeoutValue |
It stores the timeout count for the quadrature decoder module watchdog timer. This field is only available when "enableWatchdog" = true. The available value is a 16-bit unsigned number.
| uint16_t enc_config_t::filterCount |
This value should be chosen to reduce the probability of noisy samples causing an incorrect transition to be recognized. The value represent the number of consecutive samples that must agree prior to the input filter accepting an input transition. A value of 0x0 represents 3 samples. A value of 0x7 represents 10 samples. The Available range is 0 - 7.
| uint16_t enc_config_t::filterSamplePeriod |
This value should be set such that the sampling period is larger than the period of the expected noise. This value represents the sampling period (in IPBus clock cycles) of the decoder input signals. The available range is 0 - 255.
| uint32_t enc_config_t::positionCompareValue |
The available value is a 32-bit number.
| bool enc_config_t::enableModuloCountMode |
| uint32_t enc_config_t::positionModulusValue |
This value would be available only when "enableModuloCountMode" = true. The available value is a 32-bit number.
| uint32_t enc_config_t::positionInitialValue |
The available value is a 32-bit number.
| uint16_t enc_self_test_config_t::signalCount |
The available range is 0 - 255.
| uint16_t enc_self_test_config_t::signalPeriod |
The available range is 0 - 31.
