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Implements PDMIn for STM32L4 using the SAI peripheral and decimation/filtering in software.
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‎locale/circuitpython.pot

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@@ -3714,10 +3714,20 @@ msgid "offset out of bounds"
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msgstr ""
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#: ports/nrf/common-hal/audiobusio/PDMIn.c
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#: ports/stm/common-hal/audiobusio/PDMIn.c
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msgid "only bit_depth=16 is supported"
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msgstr ""
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#: ports/stm/common-hal/audiobusio/PDMIn.c
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msgid "only mono is supported"
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msgstr ""
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#: ports/stm/common-hal/audiobusio/PDMIn.c
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msgid "only oversample=64 is supported"
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msgstr ""
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#: ports/nrf/common-hal/audiobusio/PDMIn.c
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#: ports/stm/common-hal/audiobusio/PDMIn.c
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msgid "only sample_rate=16000 is supported"
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msgstr ""
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‎ports/stm/Makefile

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@@ -234,6 +234,17 @@ SRC_C += \
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peripherals/stm32$(MCU_SERIES_LOWER)/$(MCU_VARIANT_LOWER)/periph.c \
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packages/$(MCU_PACKAGE).c
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ifneq ($(CIRCUITPY_AUDIOBUSIO_PDMIN),0)
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SRC_C += \
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common-hal/audiobusio/MEMS_Audio.c \
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common-hal/audiobusio/MEMS_Audio_ll_stm32l4.c \
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common-hal/audiobusio/OpenPDMFilter.c
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SRC_STM32 += \
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$(HAL_DIR)/Src/stm32$(MCU_SERIES_LOWER)xx_hal_sai.c
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endif
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ifneq ($(CIRCUITPY_USB),0)
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SRC_C += lib/tinyusb/src/portable/st/synopsys/dcd_synopsys.c
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endif

‎ports/stm/boards/swan_r5/mpconfigboard.mk

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@@ -41,10 +41,9 @@ CIRCUITPY_PULSEIO = 1
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CIRCUITPY_PWMIO = 1
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CIRCUITPY_AUDIOPWMIO = 1
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CIRCUITPY_CANIO = 0
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CIRCUITPY_AUDIOBUSIO = 0
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CIRCUITPY_I2CTARGET = 0
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# Requires SPI, PulseIO (stub ok):
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CIRCUITPY_DISPLAYIO = 0
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CIRCUITPY_DISPLAYIO = 1
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# These modules are implemented in shared-module/ - they can be included in
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# any port once their prerequisites in common-hal are complete.
@@ -71,5 +70,8 @@ CIRCUITPY_BUSDEVICE = 0
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CIRCUITPY_KEYPAD = 1
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CIRCUITPY_RGBMATRIX = 0
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CIRCUITPY_RTC = 1
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CIRCUITPY_BUILD_EXTENSIONS = bin,uf2
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CIRCUITPY_ENABLE_MPY_NATIVE = 1
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CIRCUITPY_AUDIOBUSIO = 1
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CIRCUITPY_AUDIOBUSIO_I2SOUT = 0
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CIRCUITPY_AUDIOBUSIO_PDMIN = 1

‎ports/stm/boards/swan_r5/pins.c

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@@ -129,5 +129,8 @@ STATIC const mp_rom_map_elem_t board_module_globals_table[] = {
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{ MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
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{ MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
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{ MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
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{ MP_ROM_QSTR(MP_QSTR_MICROPHONE_CLOCK), MP_ROM_PTR(&pin_PA03) },
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{ MP_ROM_QSTR(MP_QSTR_MICROPHONE_DATA), MP_ROM_PTR(&pin_PC03) },
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};
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MP_DEFINE_CONST_DICT(board_module_globals, board_module_globals_table);

‎ports/stm/common-hal/audiobusio/I2SOut.c

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// Although IS2Out is not enabled on the STM32L4 family, this file is still required for the build to pass

‎ports/stm/common-hal/audiobusio/I2SOut.h

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// Although IS2Out is not enabled on the STM32L4 family, this file is still required for the build to pass

‎ports/stm/common-hal/audiobusio/MEMS_Audio.c

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#include <assert.h>
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#include <stm32l4xx_hal.h>
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#include "MEMS_Audio.h"
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#include "MEMS_Audio_ll.h"
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static void default_pcm_data_available(MemsAudio *audio, pcm_sample_t *pcmSamples, size_t pcmLength) {
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}
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/**
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* @brief Initializes the MemsAudio instance. Only one instance can be initialized and used at a given time.
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_init(MemsAudio *audio) {
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if (!audio->pcm_data_available) {
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audio->pcm_data_available = default_pcm_data_available;
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}
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return mems_audio_ll_init(audio);
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}
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/**
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* @brief Uninitializes the MemsAudio instance.
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_uninit(MemsAudio *audio) {
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return mems_audio_ll_uninit(audio);
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}
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/**
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* @brief Asynchronously records audio.
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*
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* @param audio
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* @param pdmBuffer
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* @param pdmBufferLength
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_record(MemsAudio *audio) {
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return mems_audio_ll_record(audio);
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}
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/**
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* @brief Pause recording audio.
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*/
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mems_audio_err_t mems_audio_pause(MemsAudio *audio) {
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return mems_audio_ll_pause(audio);
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}
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/**
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* @brief Resume recording audio.
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_resume(MemsAudio *audio) {
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return mems_audio_ll_resume(audio);
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}
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/**
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* @brief Stop recording audio and
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_stop(MemsAudio *audio) {
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return mems_audio_ll_stop(audio);
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}

‎ports/stm/common-hal/audiobusio/MEMS_Audio.h

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#ifndef _MEMS_AUDIO_H_
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#define _MEMS_AUDIO_H_
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#include <stdint.h>
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#include <stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief How many milliseconds of audio can fit in the audio buffer(s).
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* Interrupts for recieved data fire at half this duration / twice the frequency.
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*/
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#ifndef MEMS_AUDIO_MS_BUFFER
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#define MEMS_AUDIO_MS_BUFFER (1)
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#endif
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/**
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* @brief The number of bits per sample of the PCM output
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*/
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#define PCM_OUT_RESOLUTION 16
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/**
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* @brief The output frequency of PCM samples in Hz.
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*/
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#define PCM_OUT_SAMPLING_FREQUENCY 16000
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/**
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* @brief type for describing error conditions.
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*/
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typedef int32_t mems_audio_err_t;
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/**
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* @brief The datatype that holds an output PCM sample.
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*/
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typedef int16_t pcm_sample_t;
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_Static_assert(PCM_OUT_RESOLUTION==16, "Output PCM resolution must be 16-bits");
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typedef enum {
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MEMS_AUDIO_OK = 0,
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MEMS_AUDIO_ERROR_ALREADY_INITIALIZED = -1,
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MEMS_AUDIO_ERROR_NOT_INITIALIZED = -2
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} mems_audio_err_enum_t;
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#define IS_MEMS_AUDIO_ERROR(e) (e)
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#define CHECK_MEMS_AUDIO_ERROR(e) { if (IS_MEMS_AUDIO_ERROR(e)) return e; }
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#define CHECK_MEMS_AUDIO_INITIALIZED(x) { if (!x) return MEMS_AUDIO_ERROR_NOT_INITIALIZED; }
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typedef struct MemsAudio_t MemsAudio;
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/**
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* @brief Callback informing that PCM samples are available for processing.
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*/
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typedef void (*pcm_data_available_t)(MemsAudio* audio, pcm_sample_t* pcmSamples, size_t pcmLength);
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/**
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* @brief MemsAudio manages the filter, buffers and callbacks used to capture PDM audio samples and convert to PCM.
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*
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*/
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typedef struct MemsAudio_t {
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/**
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* @brief The buffer to store PCM audio samples
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*/
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volatile pcm_sample_t* volatile pcmOutputBuffer;
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/**
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* @brief The length of the PCM buffer. SHould be at least MEMS_AUDIO_PCM_BUFFER_LENGTH
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*/
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volatile size_t pcmOutputBufferLength;
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/**
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* @brief Optional callback for when PCM data is available.
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*/
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pcm_data_available_t pcm_data_available;
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void* audioImpl;
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void* userData;
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} MemsAudio;
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mems_audio_err_t mems_audio_init(MemsAudio* audio);
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/**
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* @brief Uninitializes the MemsAudio instance.
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_uninit(MemsAudio* audio);
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/**
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* @brief Asynchronously records audio.
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*
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* @param audio
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* @param pdmBuffer
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* @param pdmBufferLength
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_record(MemsAudio* audio);
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/**
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* @brief Pause recording audio.
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*/
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mems_audio_err_t mems_audio_pause(MemsAudio* audio);
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/**
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* @brief Resume recording audio.
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_resume(MemsAudio* audio);
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/**
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* @brief Stop recording audio and
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_stop(MemsAudio* audio);
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#ifdef __cplusplus
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}
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#endif
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#endif // _MEMS_AUDIO_H_

‎ports/stm/common-hal/audiobusio/MEMS_Audio_ll.h

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#ifndef _MEMS_AUDIO_LL_H_
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#define _MEMS_AUDIO_LL_H_
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#include "MEMS_Audio.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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mems_audio_err_t mems_audio_ll_init(MemsAudio *audio);
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mems_audio_err_t mems_audio_ll_uninit(MemsAudio *audio);
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/**
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* @brief Asynchronously records audio.
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*
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* @param audio
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* @param pdmBuffer
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* @param pdmBufferLength
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_ll_record(MemsAudio *audio);
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/**
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* @brief Pause recording audio.
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*/
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mems_audio_err_t mems_audio_ll_pause(MemsAudio *audio);
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/**
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* @brief Resume recording audio.
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_ll_resume(MemsAudio *audio);
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/**
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* @brief Stop recording audio and
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*
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* @param audio
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* @return mems_audio_err_t
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*/
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mems_audio_err_t mems_audio_ll_stop(MemsAudio *audio);
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#ifdef __cplusplus
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}
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#endif
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#endif // _MEMS_AUDIO_LL_H_

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