Digital Microphone Interface

Abstraction for digital microphones. More...

Data Structures
struct	pdm_io_cfg
struct	pcm_stream_cfg
struct	pdm_chan_cfg
struct	dmic_cfg

Enumerations
enum	dmic_state {   DMIC_STATE_UNINIT , DMIC_STATE_INITIALIZED , DMIC_STATE_CONFIGURED , DMIC_STATE_ACTIVE ,   DMIC_STATE_PAUSED }
enum	dmic_trigger {   DMIC_TRIGGER_STOP , DMIC_TRIGGER_START , DMIC_TRIGGER_PAUSE , DMIC_TRIGGER_RELEASE ,   DMIC_TRIGGER_RESET }
enum	pdm_lr { PDM_CHAN_LEFT , PDM_CHAN_RIGHT }

Functions
static uint32_t	dmic_build_channel_map (uint8_t channel, uint8_t pdm, enum pdm_lr lr)
static void	dmic_parse_channel_map (uint32_t channel_map_lo, uint32_t channel_map_hi, uint8_t channel, uint8_t *pdm, enum pdm_lr *lr)
static uint32_t	dmic_build_clk_skew_map (uint8_t pdm, uint8_t skew)
static int	dmic_configure (const struct device *dev, struct dmic_cfg *cfg)
static int	dmic_trigger (const struct device *dev, enum dmic_trigger cmd)
static int	dmic_read (const struct device *dev, uint8_t stream, void **buffer, size_t *size, int32_t timeout)

Detailed Description

Abstraction for digital microphones.

Enumeration Type Documentation

dmic_state

enum dmic_state

#include <include/zephyr/audio/dmic.h>

DMIC driver states

Enumerator
DMIC_STATE_UNINIT
DMIC_STATE_INITIALIZED
DMIC_STATE_CONFIGURED
DMIC_STATE_ACTIVE
DMIC_STATE_PAUSED

dmic_trigger

enum dmic_trigger

#include <include/zephyr/audio/dmic.h>

DMIC driver trigger commands

Enumerator
DMIC_TRIGGER_STOP
DMIC_TRIGGER_START
DMIC_TRIGGER_PAUSE
DMIC_TRIGGER_RELEASE
DMIC_TRIGGER_RESET

pdm_lr

enum pdm_lr

#include <include/zephyr/audio/dmic.h>

PDM Channels LEFT / RIGHT

Enumerator
PDM_CHAN_LEFT
PDM_CHAN_RIGHT

Function Documentation

dmic_build_channel_map()

static uint32_t dmic_build_channel_map ( uint8_t  channel, uint8_t  pdm, enum pdm_lr  lr  )

inlinestatic

#include <include/zephyr/audio/dmic.h>

Build the channel map to populate struct pdm_chan_cfg

Returns the map of PDM controller and LEFT/RIGHT channel shifted to the bit position corresponding to the input logical channel value

Parameters

channel	The logical channel number
pdm	The PDM hardware controller number
lr	LEFT/RIGHT channel within the chosen PDM hardware controller

Returns

Bit-map containing the PDM and L/R channel information

dmic_build_clk_skew_map()

static uint32_t dmic_build_clk_skew_map ( uint8_t  pdm, uint8_t  skew  )

inlinestatic

#include <include/zephyr/audio/dmic.h>

Build a bit map of clock skew values for each PDM channel

Returns the bit-map of clock skew value shifted to the bit position corresponding to the input PDM controller value

Parameters

pdm	The PDM hardware controller number
skew	The skew to apply for the clock output from the PDM controller

Returns

Bit-map containing the clock skew information

dmic_configure()

static int dmic_configure ( const struct device *  dev, struct dmic_cfg *  cfg  )

inlinestatic

#include <include/zephyr/audio/dmic.h>

Configure the DMIC driver and controller(s)

Configures the DMIC driver device according to the number of channels, channel mapping, PDM I/O configuration, PCM stream configuration, etc.

Parameters

dev	Pointer to the device structure for DMIC driver instance
cfg	Pointer to the structure containing the DMIC configuration

Returns

0 on success, a negative error code on failure

dmic_parse_channel_map()

static void dmic_parse_channel_map ( uint32_t  channel_map_lo, uint32_t  channel_map_hi, uint8_t  channel, uint8_t *  pdm, enum pdm_lr *  lr  )

inlinestatic

#include <include/zephyr/audio/dmic.h>

Helper function to parse the channel map in pdm_chan_cfg

Returns the PDM controller and LEFT/RIGHT channel corresponding to the channel map and the logical channel provided as input

Parameters

channel_map_lo	Lower order/significant bits of the channel map
channel_map_hi	Higher order/significant bits of the channel map
channel	The logical channel number
pdm	Pointer to the PDM hardware controller number
lr	Pointer to the LEFT/RIGHT channel within the PDM controller

dmic_read()

static int dmic_read ( const struct device *  dev, uint8_t  stream, void **  buffer, size_t *  size, int32_t  timeout  )

inlinestatic

#include <include/zephyr/audio/dmic.h>

Read received decimated PCM data stream

Optionally waits for audio to be received and provides the received audio buffer from the requested stream

Parameters

dev	Pointer to the device structure for DMIC driver instance
stream	Stream identifier
buffer	Pointer to the received buffer address
size	Pointer to the received buffer size
timeout	Timeout in milliseconds to wait in case audio is not yet received, or SYS_FOREVER_MS

Returns

0 on success, a negative error code on failure

dmic_trigger()

static int dmic_trigger ( const struct device *  dev, enum dmic_trigger  cmd  )

inlinestatic

#include <include/zephyr/audio/dmic.h>

Send a command to the DMIC driver

Sends a command to the driver to perform a specific action

Parameters

dev	Pointer to the device structure for DMIC driver instance
cmd	The command to be sent to the driver instance

Returns

0 on success, a negative error code on failure