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PDM: cleanup and fix #138

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Merged
merged 8 commits into from
Mar 8, 2021
Merged

PDM: cleanup and fix #138

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d11ce67
PDM: cleanup and fix
facchinm Feb 16, 2021
0577728
Fixed PDM::Begin return value
pennam Feb 24, 2021
c44ef02
Configure MCK_DIV according sampling frequency with fixed decimation …
pennam Feb 24, 2021
87c15a3
Increased default gain to 24db
pennam Feb 26, 2021
a216699
Split input and output channels number
pennam Feb 25, 2021
f9909c5
Add support to 11kHz 22kHz and 44kHz sampling rate
pennam Mar 1, 2021
353bec5
Reduce PDM buffer to 1KB
pennam Mar 3, 2021
8ed5830
Use linker script section to allocate PDM_BUFFER
pennam Mar 3, 2021
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105 changes: 36 additions & 69 deletions libraries/PDM/src/stm32/PDM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,15 +23,12 @@
#ifdef TARGET_STM

#include "PDM.h"
#include "audio.h"
#include "mbed.h"
extern "C" {
#include "audio.h"
}

#define AUDIO_FREQUENCY BSP_AUDIO_FREQUENCY_16K
#define AUDIO_IN_PDM_BUFFER_SIZE (uint32_t)(128)

//ALIGN_32BYTES (uint16_t recordPDMBuf[AUDIO_IN_PDM_BUFFER_SIZE]) __attribute__((section(".OPEN_AMP_SHMEM")));
// FIXME: need to add an entry for RAM_D3 to linker script
uint16_t* recordPDMBuf = (uint16_t*)0x38000000;
extern "C" uint16_t *g_pcmbuf;

PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
_dinPin(dinPin),
Expand All @@ -45,14 +42,10 @@ PDMClass::~PDMClass()
{
}

int PDMClass::begin(int channels, long sampleRate) {

_channels = channels;

// fixme: only works in stereo mode
channels = 2;
static int gain_db = -1;
static int _samplerate = -1;

setBufferSize(AUDIO_IN_PDM_BUFFER_SIZE / 4 * channels);
int PDMClass::begin(int channels, long sampleRate) {

if (isBoardRev2()) {
mbed::I2C i2c(PB_7, PB_6);
Expand All @@ -69,43 +62,36 @@ int PDMClass::begin(int channels, long sampleRate) {
i2c.write(8 << 1, data, sizeof(data));
}

BSP_AUDIO_IN_SelectInterface(AUDIO_IN_INTERFACE_PDM);
_channels = channels;
_samplerate = sampleRate;

/* Initialize audio IN at REC_FREQ*/
if (BSP_AUDIO_IN_InitEx(INPUT_DEVICE_DIGITAL_MIC, AUDIO_FREQUENCY, DEFAULT_AUDIO_IN_BIT_RESOLUTION, channels) != AUDIO_OK)
{
return 0;
if (gain_db == -1) {
gain_db = 24;
}

/* Start the record */
BSP_AUDIO_IN_Record((uint16_t*)recordPDMBuf, AUDIO_IN_PDM_BUFFER_SIZE * channels);
return 1;
//g_pcmbuf = (uint16_t*)_doubleBuffer.data();

if(py_audio_init(channels, sampleRate, gain_db, 0.9883f)) {
py_audio_start_streaming();
return 1;
}
return 0;
}

void PDMClass::end()
{
py_audio_stop_streaming();
py_audio_deinit();
}

int PDMClass::available()
{
size_t avail = _doubleBuffer.available();
if (_channels == 1) {
return avail/2;
} else {
return avail;
}
return avail;
}

int PDMClass::read(void* buffer, size_t size)
{
if (_channels == 1) {
uint16_t temp[size*2];
int read = _doubleBuffer.read(temp, size*2);
for (int i = 0; i < size; i++) {
((uint16_t*)buffer)[i] = temp[i*2];
}
return read;
}
int read = _doubleBuffer.read(buffer, size);
return read;
}
Expand All @@ -117,7 +103,9 @@ void PDMClass::onReceive(void(*function)(void))

void PDMClass::setGain(int gain)
{

gain_db = gain;
//end();
//begin(_channels, _samplerate);
}

void PDMClass::setBufferSize(int bufferSize)
Expand All @@ -127,49 +115,28 @@ void PDMClass::setBufferSize(int bufferSize)

void PDMClass::IrqHandler(bool halftranfer)
{

int start = halftranfer ? 0 : AUDIO_IN_PDM_BUFFER_SIZE;

if (BSP_AUDIO_IN_GetInterface() == AUDIO_IN_INTERFACE_PDM && _doubleBuffer.available() == 0) {

/* Invalidate Data Cache to get the updated content of the SRAM*/
SCB_InvalidateDCache_by_Addr((uint32_t *)&recordPDMBuf[start], AUDIO_IN_PDM_BUFFER_SIZE * 2);

//memcpy((uint16_t*)_doubleBuffer.data(), (uint16_t*)&recordPDMBuf[start], AUDIO_IN_PDM_BUFFER_SIZE/2);
BSP_AUDIO_IN_PDMToPCM((uint16_t*)&recordPDMBuf[start], (uint16_t*)_doubleBuffer.data());

/* Clean Data Cache to update the content of the SRAM */
SCB_CleanDCache_by_Addr((uint32_t*)_doubleBuffer.data(), AUDIO_IN_PDM_BUFFER_SIZE * 2);

if (_doubleBuffer.available() == 0) {
g_pcmbuf = (uint16_t*)_doubleBuffer.data();
audio_pendsv_callback();
_doubleBuffer.swap(_doubleBuffer.availableForWrite());
}

if (_onReceive) {
_onReceive();
}
}

extern "C" {
/**
@brief Calculates the remaining file size and new position of the pointer.
@param None
@retval None
*/
__attribute__((__used__)) void BSP_AUDIO_IN_TransferComplete_CallBack(void)
{
PDM.IrqHandler(false);
}
void PDMIrqHandler(bool halftranfer)
{
PDM.IrqHandler(halftranfer);
}

/**
@brief Manages the DMA Half Transfer complete interrupt.
@param None
@retval None
*/
__attribute__((__used__)) void BSP_AUDIO_IN_HalfTransfer_CallBack(void)
{
PDM.IrqHandler(true);
}
void PDMsetBufferSize(int size) {
PDM.setBufferSize(size);
}
}

PDMClass PDM(0, 0, 0);

#endif
#endif
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