PDM HAL

group nrf_pdm_hal

Hardware access layer for managing the Pulse Density Modulation (PDM) peripheral.

Defines

NRF_PDM_HAS_MCLKCONFIG: Symbol indicating whether master clock source configuration is available.

NRF_PDM_HAS_RATIO_CONFIG: Symbol indicating whether ratio configuration is available.

NRF_PDM_HAS_DMA_REG: Symbol indicating whether dedicated DMA register is present.

NRF_PDM_HAS_DMA_TASKS_EVENTS: Symbol indicating whether PDM DMA tasks and events are present.

NRF_PDM_GAIN_MINIMUM: Minimum value of PDM gain.

NRF_PDM_GAIN_DEFAULT: Default value of PDM gain.

NRF_PDM_GAIN_MAXIMUM: Maximum value of PDM gain.

Typedefs

typedef uint8_t nrf_pdm_gain_t: PDM gain type.

Enums

enum nrf_pdm_task_t

PDM tasks.

Values:

enumerator NRF_PDM_TASK_START: Starts continuous PDM transfer.

enumerator NRF_PDM_TASK_STOP: Stops PDM transfer.

enum nrf_pdm_event_t

PDM events.

Values:

enumerator NRF_PDM_EVENT_STARTED: PDM transfer is started.

enumerator NRF_PDM_EVENT_STOPPED: PDM transfer is finished.

enumerator NRF_PDM_EVENT_END: The PDM has written the last sample specified by MAXCNT (or the last sample after a STOP task has been received) to Data RAM.

enum nrf_pdm_int_mask_t

PDM interrupt masks.

Values:

enumerator NRF_PDM_INT_STARTED: Interrupt on EVENTS_STARTED event.

enumerator NRF_PDM_INT_STOPPED: Interrupt on EVENTS_STOPPED event.

enumerator NRF_PDM_INT_END: Interrupt on EVENTS_END event.

enum nrf_pdm_freq_t

PDM clock frequency.

Values:

enumerator NRF_PDM_FREQ_1000K: PDM_CLK = 1.000 MHz.

enumerator NRF_PDM_FREQ_1032K: PDM_CLK = 1.032 MHz.

enumerator NRF_PDM_FREQ_1067K: PDM_CLK = 1.067 MHz.

enumerator NRF_PDM_FREQ_1231K: PDM_CLK = 1.231 MHz.

enumerator NRF_PDM_FREQ_1280K: PDM_CLK = 1.280 MHz.

enumerator NRF_PDM_FREQ_1333K: PDM_CLK = 1.333 MHz.

enum nrf_pdm_ratio_t

PDM ratio between PDM_CLK and output sample rate.

Values:

enumerator NRF_PDM_RATIO_64X: Ratio of 64.

enumerator NRF_PDM_RATIO_80X: Ratio of 80.

enum nrf_pdm_mode_t

PDM operation mode.

Values:

enumerator NRF_PDM_MODE_STEREO: Sample and store one pair (Left + Right) of 16-bit samples per RAM word.

enumerator NRF_PDM_MODE_MONO: Sample and store two successive Left samples (16 bit each) per RAM word.

enum nrf_pdm_edge_t

PDM sampling mode.

Values:

enumerator NRF_PDM_EDGE_LEFTFALLING: Left (or mono) is sampled on falling edge of PDM_CLK.

enumerator NRF_PDM_EDGE_LEFTRISING: Left (or mono) is sampled on rising edge of PDM_CLK.

enum nrf_pdm_mclksrc_t

PDM master clock source selection.

Values:

enumerator NRF_PDM_MCLKSRC_PCLK32M: 32MHz peripheral clock.

enumerator NRF_PDM_MCLKSRC_ACLK: Audio PLL clock.

Functions

NRF_STATIC_INLINE void nrf_pdm_task_trigger(NRF_PDM_Type *p_reg, nrf_pdm_task_t task)

Function for triggering a PDM task.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
task – [in] PDM task.

NRF_STATIC_INLINE uint32_t nrf_pdm_task_address_get(NRF_PDM_Type const *p_reg, nrf_pdm_task_t task)

Function for getting the address of a PDM task register.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
task – [in] PDM task.

Returns:

Address of the specified PDM task.

NRF_STATIC_INLINE bool nrf_pdm_event_check(NRF_PDM_Type const *p_reg, nrf_pdm_event_t event)

Function for retrieving the state of the PDM event.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
event – [in] Event to be checked.

Return values:

true – The event has been generated.
false – The event has not been generated.

NRF_STATIC_INLINE void nrf_pdm_event_clear(NRF_PDM_Type *p_reg, nrf_pdm_event_t event)

Function for clearing a PDM event.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
event – [in] PDM event.

NRF_STATIC_INLINE uint32_t nrf_pdm_event_address_get(NRF_PDM_Type const *p_reg, nrf_pdm_event_t event)

Function for getting the address of a PDM event register.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
event – [in] PDM event.

Returns:

Address of the specified PDM event.

NRF_STATIC_INLINE void nrf_pdm_int_enable(NRF_PDM_Type *p_reg, uint32_t mask)

Function for enabling PDM interrupts.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
mask – [in] Mask of interrupts to be enabled.

NRF_STATIC_INLINE uint32_t nrf_pdm_int_enable_check(NRF_PDM_Type const *p_reg, uint32_t mask)

Function for checking if the specified interrupts are enabled.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
mask – [in] Mask of interrupts to be checked.

Returns:

Mask of enabled interrupts.

NRF_STATIC_INLINE void nrf_pdm_int_disable(NRF_PDM_Type *p_reg, uint32_t mask)

Function for disabling interrupts.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
mask – [in] Mask of interrupts to be disabled.

NRF_STATIC_INLINE void nrf_pdm_subscribe_set(NRF_PDM_Type *p_reg, nrf_pdm_task_t task, uint8_t channel)

Function for setting the subscribe configuration for a given PDM task.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
task – [in] Task for which to set the configuration.
channel – [in] Channel through which to subscribe events.

NRF_STATIC_INLINE void nrf_pdm_subscribe_clear(NRF_PDM_Type *p_reg, nrf_pdm_task_t task)

Function for clearing the subscribe configuration for a given PDM task.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
task – [in] Task for which to clear the configuration.

NRF_STATIC_INLINE void nrf_pdm_publish_set(NRF_PDM_Type *p_reg, nrf_pdm_event_t event, uint8_t channel)

Function for setting the publish configuration for a given PDM event.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
event – [in] Event for which to set the configuration.
channel – [in] Channel through which to publish the event.

NRF_STATIC_INLINE void nrf_pdm_publish_clear(NRF_PDM_Type *p_reg, nrf_pdm_event_t event)

Function for clearing the publish configuration for a given PDM event.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
event – [in] Event for which to clear the configuration.

NRF_STATIC_INLINE void nrf_pdm_enable(NRF_PDM_Type *p_reg)

Function for enabling the PDM peripheral.

The PDM peripheral must be enabled before use.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

NRF_STATIC_INLINE void nrf_pdm_disable(NRF_PDM_Type *p_reg)

Function for disabling the PDM peripheral.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

NRF_STATIC_INLINE bool nrf_pdm_enable_check(NRF_PDM_Type const *p_reg)

Function for checking if the PDM peripheral is enabled.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

Return values:

true – The PDM peripheral is enabled.
false – The PDM peripheral is not enabled.

NRF_STATIC_INLINE void nrf_pdm_mode_set(NRF_PDM_Type *p_reg, nrf_pdm_mode_t pdm_mode, nrf_pdm_edge_t pdm_edge)

Function for setting the PDM operation mode.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
pdm_mode – [in] PDM operation mode.
pdm_edge – [in] PDM sampling mode.

NRF_STATIC_INLINE void nrf_pdm_mode_get(NRF_PDM_Type const *p_reg, nrf_pdm_mode_t *p_pdm_mode, nrf_pdm_edge_t *p_pdm_edge)

Function for getting the PDM operation mode.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
p_pdm_mode – [out] PDM operation mode.
p_pdm_edge – [out] PDM sampling mode.

NRF_STATIC_INLINE void nrf_pdm_clock_set(NRF_PDM_Type *p_reg, nrf_pdm_freq_t pdm_freq)

Function for setting the PDM clock frequency.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
pdm_freq – [in] PDM clock frequency.

NRF_STATIC_INLINE nrf_pdm_freq_t nrf_pdm_clock_get(NRF_PDM_Type const *p_reg)

Function for getting the PDM clock frequency.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

Returns:

PDM clock frequency.

NRF_STATIC_INLINE void nrf_pdm_psel_connect(NRF_PDM_Type *p_reg, uint32_t psel_clk, uint32_t psel_din)

Function for setting up the PDM pins.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
psel_clk – [in] CLK pin number.
psel_din – [in] DIN pin number.

NRF_STATIC_INLINE uint32_t nrf_pdm_clk_pin_get(NRF_PDM_Type const *p_reg)

Function for getting the CLK pin selection.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

Returns:

CLK pin selection;

NRF_STATIC_INLINE uint32_t nrf_pdm_din_pin_get(NRF_PDM_Type const *p_reg)

Function for getting the DIN pin selection.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

Returns:

DIN pin selection;

NRF_STATIC_INLINE void nrf_pdm_psel_disconnect(NRF_PDM_Type *p_reg)

Function for disconnecting the PDM pins.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

NRF_STATIC_INLINE void nrf_pdm_gain_set(NRF_PDM_Type *p_reg, nrf_pdm_gain_t gain_l, nrf_pdm_gain_t gain_r)

Function for setting the PDM gain.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
gain_l – [in] Left channel gain.
gain_r – [in] Right channel gain.

NRF_STATIC_INLINE void nrf_pdm_gain_get(NRF_PDM_Type const *p_reg, nrf_pdm_gain_t *p_gain_l, nrf_pdm_gain_t *p_gain_r)

Function for getting the PDM gain.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
p_gain_l – [out] Left channel gain.
p_gain_r – [out] Right channel gain.

NRF_STATIC_INLINE void nrf_pdm_buffer_set(NRF_PDM_Type *p_reg, uint32_t *p_buffer, uint32_t num)

Function for setting the PDM sample buffer.

The amount of allocated RAM depends on the operation mode.

For stereo mode: N 32-bit words.
For mono mode: Ceil(N/2) 32-bit words.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
p_buffer – [in] Pointer to the RAM address where samples are to be written with EasyDMA.
num – [in] Number of samples to allocate memory for in EasyDMA mode.

NRF_STATIC_INLINE uint32_t *nrf_pdm_buffer_get(NRF_PDM_Type const *p_reg)

Function for getting the current PDM sample buffer address.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.

Returns:

Pointer to the current sample buffer.

NRF_STATIC_INLINE void nrf_pdm_ratio_set(NRF_PDM_Type *p_reg, nrf_pdm_ratio_t ratio)

Function for setting ratio between PDM_CLK and output sample rate.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
ratio – [in] Ratio between PDM_CLK and output sample rate.

NRF_STATIC_INLINE void nrf_pdm_mclksrc_configure(NRF_PDM_Type *p_reg, nrf_pdm_mclksrc_t mclksrc)

Function for configuring PDM master clock source.

Parameters:

p_reg – [in] Pointer to the structure of registers of the peripheral.
mclksrc – [in] Master Clock source selection.