PCNT - Pulse Counter#

Example#

The following example demonstrates basic usage of the PCNT peripheral in oversampling single input mode.

void pcnt_basic_example(void)
{
  // Configure PCNT with default settings for single input oversampling mode
  sl_hal_pcnt_init_t init = SL_HAL_PCNT_INIT_DEFAULT(SL_HAL_PCNT_MODE_OVS_SINGLE);

  // Initialize PCNT with our configuration
  sl_hal_pcnt_init(PCNT0, &init);

  // Enable the PCNT peripheral
  sl_hal_pcnt_enable(PCNT0);

  // Start the main counter
  sl_hal_pcnt_start_main_counter(PCNT0);

  // Wait for synchronization to complete
  sl_hal_pcnt_wait_sync(PCNT0);

  // Check if counter is running by reading status
  uint32_t status = sl_hal_pcnt_get_status(PCNT0);
  bool is_running = status & PCNT_STATUS_CNTRUNNING;

  if (is_running) {
    // Read current counter value
    uint32_t count_initial = sl_hal_pcnt_get_main_counter(PCNT0);

    // Optionally set counter to a specific value
    uint32_t count_new = count_initial + 10;
    sl_hal_pcnt_set_main_counter(PCNT0, count_new);

    // Read the updated counter value
    uint32_t count_after = sl_hal_pcnt_get_main_counter(PCNT0);

    // Application processing...

    // Reset the counter when needed
    sl_hal_pcnt_reset_counters(PCNT0);

    // Counter value should now be 0
    count_after = sl_hal_pcnt_get_main_counter(PCNT0);
  }

  // Stop the counter when done
  sl_hal_pcnt_stop_main_counter(PCNT0);
  sl_hal_pcnt_wait_sync(PCNT0);

  // Verify counter is stopped
  status = sl_hal_pcnt_get_status(PCNT0);
  is_running = status & PCNT_STATUS_CNTRUNNING;

  // Clean up - disable PCNT when no longer needed
  sl_hal_pcnt_disable(PCNT0);
}

Modules#

sl_hal_pcnt_init_t

Enumerations#

enum

sl_hal_pcnt_mode_t {

SL_HAL_PCNT_MODE_OVS_SINGLE = _PCNT_CFG_MODE_OVSSINGLE

SL_HAL_PCNT_MODE_EXT_CLK_SINGLE = _PCNT_CFG_MODE_EXTCLKSINGLE

SL_HAL_PCNT_MODE_EXT_CLK_QUAD = _PCNT_CFG_MODE_EXTCLKQUAD

SL_HAL_PCNT_MODE_OVS_QUAD_1X = _PCNT_CFG_MODE_OVSQUAD1X

SL_HAL_PCNT_MODE_OVS_QUAD_2X = _PCNT_CFG_MODE_OVSQUAD2X

SL_HAL_PCNT_MODE_OVS_QUAD_4X = _PCNT_CFG_MODE_OVSQUAD4X

}

PCNT mode.

enum

sl_hal_pcnt_count_event_t {

SL_HAL_PCNT_COUNT_EVENT_BOTH = _PCNT_CTRL_CNTEV_BOTH

SL_HAL_PCNT_COUNT_EVENT_UP = _PCNT_CTRL_CNTEV_UP

SL_HAL_PCNT_COUNT_EVENT_DOWN = _PCNT_CTRL_CNTEV_DOWN

}

Counter event selection.

Functions#

void

sl_hal_pcnt_init(PCNT_TypeDef *pcnt, const sl_hal_pcnt_init_t *init)

Initialize the pulse counter (PCNT).

void

sl_hal_pcnt_reset(PCNT_TypeDef *pcnt)

Reset the PCNT to the same state that it was in after a hardware reset.

void

sl_hal_pcnt_enable(PCNT_TypeDef *pcnt)

Enable the PCNT.

void

sl_hal_pcnt_disable(PCNT_TypeDef *pcnt)

Disable PCNT.

bool

sl_hal_pcnt_is_enabled(PCNT_TypeDef *pcnt)

Returns if the PCNT module is enabled or not.

void

sl_hal_pcnt_wait_ready(PCNT_TypeDef *pcnt)

Wait for disabling to finish.

void

sl_hal_pcnt_wait_sync(PCNT_TypeDef *pcnt)

Wait for ongoing sync of register(s) to the low-frequency domain to complete.

uint32_t

sl_hal_pcnt_get_status(PCNT_TypeDef *pcnt)

Get status values for the PCNT.

void

sl_hal_pcnt_enable_interrupts(PCNT_TypeDef *pcnt, uint32_t flags)

Enable one or more PCNT interrupts.

void

sl_hal_pcnt_disable_interrupts(PCNT_TypeDef *pcnt, uint32_t flags)

Disable one or more PCNT interrupts.

void

sl_hal_pcnt_clear_interrupts(PCNT_TypeDef *pcnt, uint32_t flags)

Clear one or more pending PCNT interrupts.

void

sl_hal_pcnt_set_interrupts(PCNT_TypeDef *pcnt, uint32_t flags)

Set one or more pending PCNT interrupts from SW.

uint32_t

sl_hal_pcnt_get_pending_interrupts(PCNT_TypeDef *pcnt)

Get pending PCNT interrupt flags.

uint32_t

sl_hal_pcnt_get_enabled_pending_interrupts(PCNT_TypeDef *pcnt)

Get enabled and pending PCNT interrupt flags.

void

sl_hal_pcnt_lock(PCNT_TypeDef *pcnt)

Lock PCNT registers.

void

sl_hal_pcnt_unlock(PCNT_TypeDef *pcnt)

Unlock PCNT registers.

void

sl_hal_pcnt_set_top_buffer(PCNT_TypeDef *pcnt, uint32_t value)

Set the top value buffer.

uint32_t

sl_hal_pcnt_get_top_buffer(PCNT_TypeDef *pcnt)

Get the top value buffer.

void

sl_hal_pcnt_set_top(PCNT_TypeDef *pcnt, uint32_t value)

Set the top value.

uint32_t

sl_hal_pcnt_get_top(PCNT_TypeDef *pcnt)

Get the top value.

void

sl_hal_pcnt_start_main_counter(PCNT_TypeDef *pcnt)

Start PCNT main counter.

void

sl_hal_pcnt_stop_main_counter(PCNT_TypeDef *pcnt)

Stop PCNT main counter.

void

sl_hal_pcnt_set_main_counter(PCNT_TypeDef *pcnt, uint32_t value)

Set a counter value.

uint32_t

sl_hal_pcnt_get_main_counter(PCNT_TypeDef *pcnt)

Get the main counter value.

void

sl_hal_pcnt_start_aux_counter(PCNT_TypeDef *pcnt)

Start PCNT auxiliary counter.

void

sl_hal_pcnt_stop_aux_counter(PCNT_TypeDef *pcnt)

Stop PCNT auxiliary counter.

uint32_t

sl_hal_pcnt_get_aux_counter(PCNT_TypeDef *pcnt)

Get the auxiliary counter value.

void

sl_hal_pcnt_reset_counters(PCNT_TypeDef *pcnt)

Reset PCNT counters.

Macros#

#define

SL_HAL_PCNT_REF_VALID (pcnt_ref)

Check if PCNT module is valid.

#define

SL_HAL_PCNT_MAX_COUNT (pcnt_ref)

Return PCNT module max count.

#define

SL_HAL_PCNT_INIT_DEFAULT (init_mode)

Default configuration for PCNT initialization structure.

Enumeration Documentation#

sl_hal_pcnt_mode_t#

sl_hal_pcnt_mode_t

PCNT mode.

Enumerator
SL_HAL_PCNT_MODE_OVS_SINGLE	Single input LFACLK oversampling mode (available in EM0-EM3).
SL_HAL_PCNT_MODE_EXT_CLK_SINGLE	Externally clocked single input counter mode (available in EM0-EM3).
SL_HAL_PCNT_MODE_EXT_CLK_QUAD	Externally clocked quadrature decoder mode (available in EM0-EM3).
SL_HAL_PCNT_MODE_OVS_QUAD_1X	LFACLK oversampling quadrature decoder 1X mode (available in EM0-EM3).
SL_HAL_PCNT_MODE_OVS_QUAD_2X	LFACLK oversampling quadrature decoder 2X mode (available in EM0-EM3).
SL_HAL_PCNT_MODE_OVS_QUAD_4X	LFACLK oversampling quadrature decoder 4X mode (available in EM0-EM3).

sl_hal_pcnt_count_event_t#

sl_hal_pcnt_count_event_t

Counter event selection.

Enumerator
SL_HAL_PCNT_COUNT_EVENT_BOTH	Counts up on up-count and down on down-count events.
SL_HAL_PCNT_COUNT_EVENT_UP	Only counts up on up-count events.
SL_HAL_PCNT_COUNT_EVENT_DOWN	Only counts down on down-count events.

Function Documentation#

sl_hal_pcnt_init#

void sl_hal_pcnt_init (PCNT_TypeDef * pcnt, const sl_hal_pcnt_init_t * init)

Initialize the pulse counter (PCNT).

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
const sl_hal_pcnt_init_t *	[in]	init	Pointer to the initialization structure.

Notice that the EM23GRPACLK must be enabled in all modes, since some basic setup is done with this clock even if the external pin clock usage mode is chosen. The pulse counter clock for the selected instance must also be enabled prior to initialization.

Notice that pins used by the PCNT module must be properly configured by the user explicitly through setting the ROUTE register for the PCNT to work as intended.

sl_hal_pcnt_reset#

void sl_hal_pcnt_reset (PCNT_TypeDef * pcnt)

Reset the PCNT to the same state that it was in after a hardware reset.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

sl_hal_pcnt_enable#

void sl_hal_pcnt_enable (PCNT_TypeDef * pcnt)

Enable the PCNT.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

sl_hal_pcnt_disable#

void sl_hal_pcnt_disable (PCNT_TypeDef * pcnt)

Disable PCNT.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

sl_hal_pcnt_is_enabled#

bool sl_hal_pcnt_is_enabled (PCNT_TypeDef * pcnt)

Returns if the PCNT module is enabled or not.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Returns

Returns true if the module is enabled.

sl_hal_pcnt_wait_ready#

void sl_hal_pcnt_wait_ready (PCNT_TypeDef * pcnt)

Wait for disabling to finish.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

sl_hal_pcnt_wait_sync#

void sl_hal_pcnt_wait_sync (PCNT_TypeDef * pcnt)

Wait for ongoing sync of register(s) to the low-frequency domain to complete.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

sl_hal_pcnt_get_status#

uint32_t sl_hal_pcnt_get_status (PCNT_TypeDef * pcnt)

Get status values for the PCNT.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Returns

Current status values.

sl_hal_pcnt_enable_interrupts#

void sl_hal_pcnt_enable_interrupts (PCNT_TypeDef * pcnt, uint32_t flags)

Enable one or more PCNT interrupts.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
uint32_t	[in]	flags	PCNT interrupt source(s) to enable. Use one or more valid interrupt flags for the PCNT module (PCNT_IF_nnn) OR'ed together.

sl_hal_pcnt_disable_interrupts#

void sl_hal_pcnt_disable_interrupts (PCNT_TypeDef * pcnt, uint32_t flags)

Disable one or more PCNT interrupts.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
uint32_t	[in]	flags	PCNT interrupt source(s) to disable. Use one or more valid interrupt flags for the PCNT module (PCNT_IF_nnn) OR'ed together.

sl_hal_pcnt_clear_interrupts#

void sl_hal_pcnt_clear_interrupts (PCNT_TypeDef * pcnt, uint32_t flags)

Clear one or more pending PCNT interrupts.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
uint32_t	[in]	flags	Pending PCNT interrupt source(s) to clear. Use one or more valid interrupt flags for the PCNT module (PCNT_IF_nnn) OR'ed together.

sl_hal_pcnt_set_interrupts#

void sl_hal_pcnt_set_interrupts (PCNT_TypeDef * pcnt, uint32_t flags)

Set one or more pending PCNT interrupts from SW.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
uint32_t	[in]	flags	PCNT interrupt source(s) to set to pending. Use one or more valid interrupt flags for the PCNT module (PCNT_IF_nnn) OR'ed together.

sl_hal_pcnt_get_pending_interrupts#

uint32_t sl_hal_pcnt_get_pending_interrupts (PCNT_TypeDef * pcnt)

Get pending PCNT interrupt flags.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Note

Event bits are not cleared by this function.

Returns

PCNT interrupt source(s) pending. Returns one or more valid interrupt flags for the PCNT module (PCNT_IF_nnn) OR'ed together.

sl_hal_pcnt_get_enabled_pending_interrupts#

uint32_t sl_hal_pcnt_get_enabled_pending_interrupts (PCNT_TypeDef * pcnt)

Get enabled and pending PCNT interrupt flags.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Useful for handling more interrupt sources in the same interrupt handler.

Note

Interrupt flags are not cleared by this function.

Returns

Pending and enabled PCNT interrupt sources. The return value is the bitwise AND combination of
- the OR combination of enabled interrupt sources in PCNTx_IEN_nnn register (PCNTx_IEN_nnn) and
- the OR combination of valid interrupt flags of the PCNT module (PCNTx_IF_nnn).

sl_hal_pcnt_lock#

void sl_hal_pcnt_lock (PCNT_TypeDef * pcnt)

Lock PCNT registers.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Note

When PCNT registers are locked PCNT_CFG, PCNT_EN, PCNT_SWRST, PCNT_CMD, PCNT_CTRL, PCNT_OVSCTRL, PCNT_CNT, PCNT_TOP, and PCNT_TOPB registers cannot be written to.

sl_hal_pcnt_unlock#

void sl_hal_pcnt_unlock (PCNT_TypeDef * pcnt)

Unlock PCNT registers.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to thePCNT peripheral register block.

sl_hal_pcnt_set_top_buffer#

void sl_hal_pcnt_set_top_buffer (PCNT_TypeDef * pcnt, uint32_t value)

Set the top value buffer.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
uint32_t	[in]	value	Value to set in top value buffer register.

When top value buffer register is updated, value is loaded into top value register at the next wrap around. This feature is useful in order to update top value safely when PCNT is running. This won't happen if SL_HAL_PCNT_COUNT_EVENT_BOTH is used.

sl_hal_pcnt_get_top_buffer#

uint32_t sl_hal_pcnt_get_top_buffer (PCNT_TypeDef * pcnt)

Get the top value buffer.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Returns

Current top value buffer.

sl_hal_pcnt_set_top#

void sl_hal_pcnt_set_top (PCNT_TypeDef * pcnt, uint32_t value)

Set the top value.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
uint32_t	[in]	value	Value to set in top value register.

sl_hal_pcnt_get_top#

uint32_t sl_hal_pcnt_get_top (PCNT_TypeDef * pcnt)

Get the top value.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Returns

Current top value.

sl_hal_pcnt_start_main_counter#

void sl_hal_pcnt_start_main_counter (PCNT_TypeDef * pcnt)

Start PCNT main counter.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

This function will send a start command to the PCNT peripheral. The PCNT peripheral will use some LF clock ticks before the command is executed. The sl_hal_pcnt_wait_sync() function can be used to wait for the start command to be executed.

sl_hal_pcnt_stop_main_counter#

void sl_hal_pcnt_stop_main_counter (PCNT_TypeDef * pcnt)

Stop PCNT main counter.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

This function will send a stop command to the PCNT peripheral. The PCNT peripheral will use some LF clock ticks before the command is executed. The sl_hal_pcnt_wait_sync() function can be used to wait for the stop command to be executed.

sl_hal_pcnt_set_main_counter#

void sl_hal_pcnt_set_main_counter (PCNT_TypeDef * pcnt, uint32_t value)

Set a counter value.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.
uint32_t	[in]	value	Value to set in counter register.

Note

This function could stall until synchronization to low-frequency domain is completed. For that reason, it should normally not be used when an external clock is used for the PCNT module, since stall time may be undefined.

sl_hal_pcnt_get_main_counter#

uint32_t sl_hal_pcnt_get_main_counter (PCNT_TypeDef * pcnt)

Get the main counter value.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Returns

Current main counter value.

sl_hal_pcnt_start_aux_counter#

void sl_hal_pcnt_start_aux_counter (PCNT_TypeDef * pcnt)

Start PCNT auxiliary counter.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

sl_hal_pcnt_stop_aux_counter#

void sl_hal_pcnt_stop_aux_counter (PCNT_TypeDef * pcnt)

Stop PCNT auxiliary counter.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

sl_hal_pcnt_get_aux_counter#

uint32_t sl_hal_pcnt_get_aux_counter (PCNT_TypeDef * pcnt)

Get the auxiliary counter value.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	Pointer to the PCNT peripheral register block.

Returns

Current auxiliary counter value.

sl_hal_pcnt_reset_counters#

void sl_hal_pcnt_reset_counters (PCNT_TypeDef * pcnt)

Reset PCNT counters.

Parameters

Type	Direction	Argument Name	Description
PCNT_TypeDef *	[in]	pcnt	A pointer to the PCNT peripheral register block.