PDM HAL

nRF5 SDK v12.1.0

nRF52 only: Hardware abstraction layer for accessing the pulse density modulation (PDM) peripheral. More...

Macros

#define NRF_PDM_GAIN_MINIMUM 0x00
#define NRF_PDM_GAIN_DEFAULT 0x28
#define NRF_PDM_GAIN_MAXIMUM 0x50

Typedefs

typedef uint8_t nrf_pdm_gain_t

Enumerations

enum nrf_pdm_task_t {
NRF_PDM_TASK_START = offsetof(NRF_PDM_Type, TASKS_START),
NRF_PDM_TASK_STOP = offsetof(NRF_PDM_Type, TASKS_STOP)
}
PDM tasks. More...
enum nrf_pdm_event_t {
NRF_PDM_EVENT_STARTED = offsetof(NRF_PDM_Type, EVENTS_STARTED),
NRF_PDM_EVENT_STOPPED = offsetof(NRF_PDM_Type, EVENTS_STOPPED),
NRF_PDM_EVENT_END = offsetof(NRF_PDM_Type, EVENTS_END)
}
PDM events. More...
enum nrf_pdm_int_mask_t {
NRF_PDM_INT_STARTED = PDM_INTENSET_STARTED_Msk,
NRF_PDM_INT_STOPPED = PDM_INTENSET_STOPPED_Msk,
NRF_PDM_INT_END = PDM_INTENSET_END_Msk
}
PDM interrupt masks. More...
enum nrf_pdm_freq_t {
NRF_PDM_FREQ_1000K = PDM_PDMCLKCTRL_FREQ_1000K,
NRF_PDM_FREQ_1032K = PDM_PDMCLKCTRL_FREQ_Default,
NRF_PDM_FREQ_1067K = PDM_PDMCLKCTRL_FREQ_1067K
}
PDM clock frequency. More...
enum nrf_pdm_mode_t {
NRF_PDM_MODE_STEREO = PDM_MODE_OPERATION_Stereo,
NRF_PDM_MODE_MONO = PDM_MODE_OPERATION_Mono
}
PDM operation mode. More...
enum nrf_pdm_edge_t {
NRF_PDM_EDGE_LEFTFALLING = PDM_MODE_EDGE_LeftFalling,
NRF_PDM_EDGE_LEFTRISING = PDM_MODE_EDGE_LeftRising
}
PDM sampling mode. More...

Functions

__STATIC_INLINE void nrf_pdm_task_trigger ( nrf_pdm_task_t pdm_task)
Function for triggering a PDM task. More...
__STATIC_INLINE uint32_t nrf_pdm_task_address_get ( nrf_pdm_task_t pdm_task)
Function for getting the address of a PDM task register. More...
__STATIC_INLINE bool nrf_pdm_event_check ( nrf_pdm_event_t pdm_event)
Function for getting the state of a PDM event. More...
__STATIC_INLINE void nrf_pdm_event_clear ( nrf_pdm_event_t pdm_event)
Function for clearing a PDM event. More...
__STATIC_INLINE volatile uint32_t * nrf_pdm_event_address_get ( nrf_pdm_event_t pdm_event)
Function for getting the address of a PDM event register. More...
__STATIC_INLINE void nrf_pdm_int_enable (uint32_t pdm_int_mask)
Function for enabling PDM interrupts. More...
__STATIC_INLINE bool nrf_pdm_int_enable_check (uint32_t pdm_int_mask)
Function for retrieving the state of PDM interrupts. More...
__STATIC_INLINE void nrf_pdm_int_disable (uint32_t pdm_int_mask)
Function for disabling interrupts. More...
__STATIC_INLINE void nrf_pdm_enable (void)
Function for enabling the PDM peripheral. More...
__STATIC_INLINE void nrf_pdm_disable (void)
Function for disabling the PDM peripheral.
__STATIC_INLINE bool nrf_pdm_enable_check (void)
Function for checking if the PDM peripheral is enabled. More...
__STATIC_INLINE void nrf_pdm_mode_set ( nrf_pdm_mode_t pdm_mode, nrf_pdm_edge_t pdm_edge)
Function for setting the PDM operation mode. More...
__STATIC_INLINE void nrf_pdm_mode_get ( nrf_pdm_mode_t *p_pdm_mode, nrf_pdm_edge_t *p_pdm_edge)
Function for getting the PDM operation mode. More...
__STATIC_INLINE void nrf_pdm_clock_set ( nrf_pdm_freq_t pdm_freq)
Function for setting the PDM clock frequency. More...
__STATIC_INLINE nrf_pdm_freq_t nrf_pdm_clock_get (void)
Function for getting the PDM clock frequency.
__STATIC_INLINE void nrf_pdm_psel_connect (uint32_t psel_clk, uint32_t psel_din)
Function for setting up the PDM pins. More...
__STATIC_INLINE void nrf_pdm_psel_disconnect ()
Function for disconnecting the PDM pins.
__STATIC_INLINE void nrf_pdm_gain_set (nrf_pdm_gain_t gain_l, nrf_pdm_gain_t gain_r)
Function for setting the PDM gain. More...
__STATIC_INLINE void nrf_pdm_gain_get (nrf_pdm_gain_t *p_gain_l, nrf_pdm_gain_t *p_gain_r)
Function for getting the PDM gain. More...
__STATIC_INLINE void nrf_pdm_buffer_set (uint32_t *p_buffer, uint32_t num)
Function for setting the PDM sample buffer. More...
__STATIC_INLINE uint32_t * nrf_pdm_buffer_get ()
Function for getting the current PDM sample buffer address. More...

Detailed Description

nRF52 only: Hardware abstraction layer for accessing the pulse density modulation (PDM) peripheral.

Enumeration Type Documentation

PDM sampling mode.

Enumerator
NRF_PDM_EDGE_LEFTFALLING

Left (or mono) is sampled on falling edge of PDM_CLK.

NRF_PDM_EDGE_LEFTRISING

Left (or mono) is sampled on rising edge of PDM_CLK.

PDM events.

Enumerator
NRF_PDM_EVENT_STARTED

PDM transfer has started.

NRF_PDM_EVENT_STOPPED

PDM transfer has finished.

NRF_PDM_EVENT_END

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

PDM clock frequency.

Enumerator
NRF_PDM_FREQ_1000K

PDM_CLK = 1.000 MHz.

NRF_PDM_FREQ_1032K

PDM_CLK = 1.032 MHz.

NRF_PDM_FREQ_1067K

PDM_CLK = 1.067 MHz.

PDM interrupt masks.

Enumerator
NRF_PDM_INT_STARTED

Interrupt on EVENTS_STARTED event.

NRF_PDM_INT_STOPPED

Interrupt on EVENTS_STOPPED event.

NRF_PDM_INT_END

Interrupt on EVENTS_END event.

PDM operation mode.

Enumerator
NRF_PDM_MODE_STEREO

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

NRF_PDM_MODE_MONO

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

PDM tasks.

Enumerator
NRF_PDM_TASK_START

Starts continuous PDM transfer.

NRF_PDM_TASK_STOP

Stops PDM transfer.

Function Documentation

__STATIC_INLINE uint32_t* nrf_pdm_buffer_get ( )

Function for getting the current PDM sample buffer address.

Returns
Pointer to the current sample buffer.
__STATIC_INLINE void nrf_pdm_buffer_set ( uint32_t * p_buffer ,
uint32_t num
)

Function for setting the PDM sample buffer.

Parameters
[in] p_buffer Pointer to the RAM address where samples should be written with EasyDMA.
[in] num Number of samples to allocate memory for in EasyDMA mode.

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.
__STATIC_INLINE void nrf_pdm_clock_set ( nrf_pdm_freq_t pdm_freq )

Function for setting the PDM clock frequency.

Parameters
[in] pdm_freq PDM clock frequency.
__STATIC_INLINE void nrf_pdm_enable ( void )

Function for enabling the PDM peripheral.

The PDM peripheral must be enabled before use.

__STATIC_INLINE bool nrf_pdm_enable_check ( void )

Function for checking if the PDM peripheral is enabled.

Return values
true If the PDM peripheral is enabled.
false If the PDM peripheral is not enabled.
__STATIC_INLINE volatile uint32_t* nrf_pdm_event_address_get ( nrf_pdm_event_t pdm_event )

Function for getting the address of a PDM event register.

Parameters
[in] pdm_event PDM event.
Returns
Address of the specified PDM event.
__STATIC_INLINE bool nrf_pdm_event_check ( nrf_pdm_event_t pdm_event )

Function for getting the state of a PDM event.

Parameters
[in] pdm_event PDM event.
Returns
State of the specified PDM event.
__STATIC_INLINE void nrf_pdm_event_clear ( nrf_pdm_event_t pdm_event )

Function for clearing a PDM event.

Parameters
[in] pdm_event PDM event.
__STATIC_INLINE void nrf_pdm_gain_get ( nrf_pdm_gain_t * p_gain_l ,
nrf_pdm_gain_t * p_gain_r
)

Function for getting the PDM gain.

Parameters
[out] p_gain_l Left channel gain.
[out] p_gain_r Right channel gain.
__STATIC_INLINE void nrf_pdm_gain_set ( nrf_pdm_gain_t gain_l ,
nrf_pdm_gain_t gain_r
)

Function for setting the PDM gain.

Parameters
[in] gain_l Left channel gain.
[in] gain_r Right channel gain.
__STATIC_INLINE void nrf_pdm_int_disable ( uint32_t pdm_int_mask )

Function for disabling interrupts.

Parameters
pdm_int_mask Interrupts to disable.
__STATIC_INLINE void nrf_pdm_int_enable ( uint32_t pdm_int_mask )

Function for enabling PDM interrupts.

Parameters
[in] pdm_int_mask Interrupts to enable.
__STATIC_INLINE bool nrf_pdm_int_enable_check ( uint32_t pdm_int_mask )

Function for retrieving the state of PDM interrupts.

Parameters
[in] pdm_int_mask Interrupts to check.
Return values
true If all specified interrupts are enabled.
false If at least one of the given interrupts is not enabled.
__STATIC_INLINE void nrf_pdm_mode_get ( nrf_pdm_mode_t * p_pdm_mode ,
nrf_pdm_edge_t * p_pdm_edge
)

Function for getting the PDM operation mode.

Parameters
[out] p_pdm_mode PDM operation mode.
[out] p_pdm_edge PDM sampling mode.
__STATIC_INLINE void nrf_pdm_mode_set ( nrf_pdm_mode_t pdm_mode ,
nrf_pdm_edge_t pdm_edge
)

Function for setting the PDM operation mode.

Parameters
[in] pdm_mode PDM operation mode.
[in] pdm_edge PDM sampling mode.
__STATIC_INLINE void nrf_pdm_psel_connect ( uint32_t psel_clk ,
uint32_t psel_din
)

Function for setting up the PDM pins.

Parameters
[in] psel_clk CLK pin number.
[in] psel_din DIN pin number.
__STATIC_INLINE uint32_t nrf_pdm_task_address_get ( nrf_pdm_task_t pdm_task )

Function for getting the address of a PDM task register.

Parameters
[in] pdm_task PDM task.
Returns
Address of the specified PDM task.
__STATIC_INLINE void nrf_pdm_task_trigger ( nrf_pdm_task_t pdm_task )

Function for triggering a PDM task.

Parameters
[in] pdm_task PDM task.