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Portenta: PDM: cut out unusable starting PDM samples. #349

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Merged
merged 1 commit into from
Oct 20, 2021
Merged

Portenta: PDM: cut out unusable starting PDM samples. #349

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2 changes: 2 additions & 0 deletions libraries/PDM/src/PDM.h
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Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,8 @@ class PDMClass
int _gain;
int _init;

int _cutSamples;

PDMDoubleBuffer _doubleBuffer;

void (*_onReceive)(void);
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3 changes: 2 additions & 1 deletion libraries/PDM/src/nrf52/PDM.cpp
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Expand Up @@ -43,7 +43,8 @@ PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
_gain(-1),
_channels(-1),
_samplerate(-1),
_init(-1)
_init(-1),
_cutSamples(0)
{
}

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13 changes: 7 additions & 6 deletions libraries/PDM/src/rp2040/PDM.cpp
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Expand Up @@ -53,7 +53,8 @@ PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
_gain(-1),
_channels(-1),
_samplerate(-1),
_init(-1)
_init(-1),
_cutSamples(100)
{
}

Expand Down Expand Up @@ -138,6 +139,8 @@ int PDMClass::begin(int channels, int sampleRate)
true // Start immediately
);

_cutSamples = 100;

_init = 1;

return 1;
Expand Down Expand Up @@ -190,8 +193,6 @@ void PDMClass::setBufferSize(int bufferSize)

void PDMClass::IrqHandler(bool halftranfer)
{
static int cutSamples = 100;

// Clear the interrupt request.
dma_hw->ints0 = 1u << dmaChannel;
// Restart dma pointing to the other buffer
Expand All @@ -210,9 +211,9 @@ void PDMClass::IrqHandler(bool halftranfer)
Open_PDM_Filter_64(rawBuffer[rawBufferIndex], finalBuffer, 1, &filter);
}

if (cutSamples) {
memset(finalBuffer, 0, cutSamples);
cutSamples = 0;
if (_cutSamples) {
memset(finalBuffer, 0, _cutSamples);
_cutSamples = 0;
}

// swap final buffer and raw buffers' indexes
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13 changes: 10 additions & 3 deletions libraries/PDM/src/stm32/PDM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,8 @@ PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
_gain(-1),
_channels(-1),
_samplerate(-1),
_init(-1)
_init(-1),
_cutSamples(4)
{
_instance = this;
}
Expand Down Expand Up @@ -80,6 +81,8 @@ int PDMClass::begin(int channels, int sampleRate) {
g_pcmbuf = (uint16_t*)_doubleBuffer.data();
_doubleBuffer.swap(0);

_cutSamples = 4 * channels;

if(py_audio_init(channels, sampleRate, _gain, 0.9883f)) {
py_audio_start_streaming();
_init = 1;
Expand Down Expand Up @@ -146,8 +149,12 @@ void PDMClass::IrqHandler(bool halftranfer)
_doubleBuffer.swap(g_pcmbuf_size);
g_pcmbuf = (uint16_t*)_doubleBuffer.data();
g_pcmbuf_size = 0;
if (_onReceive) {
_onReceive();
if(_cutSamples == 0) {
if (_onReceive) {
_onReceive();
}
} else {
_cutSamples--;
}
}
}
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