Merge pull request #198 from pennam/pdm_buffer

PDM.setBufferSize()

Author: facchinm

libraries/PDM/src/PDM.h

@@ -42,6 +42,7 @@ class PDMClass
   //NANO 33 BLE SENSe min 0 max 80
   void setGain(int gain);
   void setBufferSize(int bufferSize);
+  size_t getBufferSize();
 
 // private:
   void IrqHandler(bool halftranfer);

libraries/PDM/src/stm32/PDM.cpp

@@ -70,7 +70,10 @@ int PDMClass::begin(int channels, int sampleRate) {
     _gain = 24;
   }
 
-  if(py_audio_init(channels, sampleRate, _gain, 0.9883f)) {
+  g_pcmbuf = (uint16_t*)_doubleBuffer.data();
+  _doubleBuffer.swap(0);
+
+  if(py_audio_init(channels, sampleRate, gain_db, 0.9883f)) {
     py_audio_start_streaming();
     _init = 1;
     return 1;
@@ -114,16 +117,29 @@ void PDMClass::setBufferSize(int bufferSize)
   _doubleBuffer.setSize(bufferSize);
 }
 
+size_t PDMClass::getBufferSize()
+{
+  return _doubleBuffer.getSize();
+}
+
+#define HALF_TRANSFER_SIZE  (64*_channels)
+static int g_pcmbuf_size=0;
+
 void PDMClass::IrqHandler(bool halftranfer)
 {
-  if (_doubleBuffer.available() == 0) {
-    g_pcmbuf = (uint16_t*)_doubleBuffer.data();
+  if (g_pcmbuf_size < _doubleBuffer.getSize()) {
     audio_pendsv_callback();
-    _doubleBuffer.swap(_doubleBuffer.availableForWrite());
-  }
-
-  if (_onReceive) {
-      _onReceive();
+    g_pcmbuf += (HALF_TRANSFER_SIZE/2);
+    g_pcmbuf_size += HALF_TRANSFER_SIZE;
+
+    if(g_pcmbuf_size == _doubleBuffer.getSize()) {
+      _doubleBuffer.swap(g_pcmbuf_size);
+      g_pcmbuf = (uint16_t*)_doubleBuffer.data();
+      g_pcmbuf_size = 0;
+      if (_onReceive) {
+        _onReceive();
+      }
+    }
   }
 }
 
@@ -136,6 +152,10 @@ void PDMIrqHandler(bool halftranfer)
 void PDMsetBufferSize(int size) {
   PDM.setBufferSize(size);
 }
+
+size_t PDMgetBufferSize() {
+  return PDM.getBufferSize();
+}
 }
 
 PDMClass PDM(0, 0, 0);

libraries/PDM/src/stm32/audio.c

@@ -303,8 +303,11 @@ int py_audio_init(size_t channels, uint32_t frequency, int gain_db, float highpa
         PDM_Filter_setConfig(&PDM_FilterHandler[i], &PDM_FilterConfig[i]);
     }
 
-    PDMsetBufferSize(samples_per_channel * g_o_channels * sizeof(int16_t));
-    //g_pcmbuf = malloc(samples_per_channel * g_channels * sizeof(int16_t));
+    uint32_t min_buff_size = samples_per_channel * g_o_channels * sizeof(int16_t);
+    uint32_t buff_size = PDMgetBufferSize();
+    if(buff_size < min_buff_size) {
+      PDMsetBufferSize(min_buff_size);
+    }
 
     return 1;
 }

libraries/PDM/src/utility/PDMDoubleBuffer.cpp

@@ -37,6 +37,11 @@ void PDMDoubleBuffer::setSize(int size)
   reset();
 }
 
+size_t PDMDoubleBuffer::getSize()
+{
+  return _size;
+}
+
 void PDMDoubleBuffer::reset()
 {
   _buffer[0] = (uint8_t*)realloc(_buffer[0], _size);

libraries/PDM/src/utility/PDMDoubleBuffer.h

@@ -31,6 +31,7 @@ class PDMDoubleBuffer
   virtual ~PDMDoubleBuffer();
 
   void setSize(int size);
+  size_t getSize();
 
   void reset();