circuitpython/ports/stm/common-hal/audiobusio/PDMIn.c

200 lines
6.5 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2022 Matthew McGowan for Blues Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include "common-hal/audiobusio/PDMIn.h"
#include "shared-bindings/audiobusio/PDMIn.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "py/runtime.h"
#include "supervisor/memory.h"
#include "MEMS_Audio_ll_stm32l4.h"
MemsAudio memsAudio;
MemsAudio_STM32L4SAIPDM memsAudioImpl;
pdm_sample_t pdmBuffer[MEMS_AUDIO_PDM_BUFFER_LENGTH];
audiobusio_pdmin_obj_t *instance;
static bool pdm_data_available(MemsAudio_STM32L4SAIPDM *impl, uint8_t *pdmBuffer, size_t pdmBufferLength);
// Caller validates that pins are free.
void common_hal_audiobusio_pdmin_construct(audiobusio_pdmin_obj_t *self,
const mcu_pin_obj_t *clock_pin,
const mcu_pin_obj_t *data_pin,
uint32_t sample_rate,
uint8_t bit_depth,
bool mono,
uint8_t oversample) {
self->sample_rate = sample_rate;
self->mono = mono;
self->oversample = oversample;
self->recording_complete = true;
if (!mono) {
mp_raise_ValueError(translate("only mono is supported"));
}
if (sample_rate != 16000) {
mp_raise_ValueError(translate("only sample_rate=16000 is supported"));
}
if (bit_depth != 16) {
mp_raise_ValueError(translate("only bit_depth=16 is supported"));
}
if (oversample != 64) {
mp_raise_ValueError(translate("only oversample=64 is supported"));
}
// wait for the previous instance to finish.
if (instance) {
common_hal_audiobusio_pdmin_deinit(instance);
}
instance = self;
memset(&memsAudio, 0, sizeof(memsAudio));
memset(&memsAudioImpl, 0, sizeof(memsAudioImpl));
common_hal_mcu_pin_claim(clock_pin);
self->clock_pin = clock_pin;
common_hal_mcu_pin_claim(data_pin);
self->data_pin = data_pin;
self->audio = &memsAudio;
self->audio_impl = &memsAudioImpl;
self->audio_impl->pdmBuffer = pdmBuffer;
self->audio_impl->pdmBufferLength = sizeof(pdmBuffer) / sizeof(pdmBuffer[0]);
self->audio_impl->pdm_data_available = pdm_data_available;
mems_audio_init_stm32l4_sai_pdm(self->audio, self->audio_impl);
mems_audio_record(self->audio);
mems_audio_pause(self->audio);
}
bool common_hal_audiobusio_pdmin_deinited(audiobusio_pdmin_obj_t *self) {
return self->clock_pin == NULL;
}
void wait_dma_complete(audiobusio_pdmin_obj_t *self) {
while (!self->recording_complete) {
MICROPY_VM_HOOK_LOOP;
}
}
void common_hal_audiobusio_pdmin_deinit(audiobusio_pdmin_obj_t *self) {
if (instance != self) {
return;
}
instance = NULL;
if (self->audio) {
wait_dma_complete(self);
mems_audio_stop(self->audio);
mems_audio_uninit(self->audio);
self->audio = NULL;
self->audio_impl = NULL;
}
if (self->data_pin) {
common_hal_reset_pin(self->data_pin);
self->data_pin = NULL;
}
if (self->clock_pin) {
common_hal_reset_pin(self->clock_pin);
self->clock_pin = NULL;
}
}
uint8_t common_hal_audiobusio_pdmin_get_bit_depth(audiobusio_pdmin_obj_t *self) {
return 16;
}
uint32_t common_hal_audiobusio_pdmin_get_sample_rate(audiobusio_pdmin_obj_t *self) {
return 16000;
}
static bool pdm_data_available(MemsAudio_STM32L4SAIPDM *impl, uint8_t *pdmBuffer, size_t pdmBufferLength) {
// update the filter with the correct number of samples
audiobusio_pdmin_obj_t *pdmIn = (audiobusio_pdmin_obj_t *)(impl->audio->userData);
MemsAudio *audio = impl->audio;
uint32_t pcmSamplesAvailable = pdmBufferLength * 8 / PDM_IN_DECIMATION_FACTOR;
if (pcmSamplesAvailable > audio->pcmOutputBufferLength) {
pcmSamplesAvailable = audio->pcmOutputBufferLength;
}
// ensure the filter doesn't try to produce more samples than available
pdmIn->audio_impl->filter.nSamples = pcmSamplesAvailable;
return pcmSamplesAvailable > 0;
}
static void pcm_data_available(MemsAudio *audio, int16_t *pcmBuffer, size_t pcmBufferLength) {
// data is already in the output buffer
audiobusio_pdmin_obj_t *pdmIn = (audiobusio_pdmin_obj_t *)(audio->userData);
// if DMA copies more data than will fit into the output buffer, crop the length to what will fit
if (audio->pcmOutputBufferLength < pcmBufferLength) {
pcmBufferLength = audio->pcmOutputBufferLength;
}
audio->pcmOutputBuffer += pcmBufferLength;
audio->pcmOutputBufferLength -= pcmBufferLength;
if (audio->pcmOutputBufferLength == 0) {
pdmIn->recording_complete = true;
mems_audio_pause(audio);
}
}
uint32_t common_hal_audiobusio_pdmin_record_to_buffer(audiobusio_pdmin_obj_t *self,
uint16_t *output_buffer, uint32_t output_buffer_length) {
MemsAudio *audio = self->audio;
wait_dma_complete(self);
audio->pcmOutputBuffer = (int16_t *)output_buffer;
audio->pcmOutputBufferLength = output_buffer_length;
audio->pcm_data_available = pcm_data_available;
audio->userData = self; /// reference back to the PDMIn instance
self->recording_complete = false;
mems_audio_err_t err = mems_audio_resume(audio);
if (!IS_MEMS_AUDIO_ERROR(err)) {
wait_dma_complete(self);
}
mems_audio_pause(audio);
int samples_output = (int)(output_buffer_length) - audio->pcmOutputBufferLength;
// convert from signed to unsigned (min-point moves from 0 to 32k)
for (int i = 0; i < samples_output; i++) {
output_buffer[i] += 0x8000;
}
return samples_output;
}