Giga: Add PDM library

Author: giulcioffi

libraries/PDM/src/giga/PDM.cpp

@@ -0,0 +1,156 @@
+/*
+  PDM.cpp - library to interface with STM32 PDM microphones
+  Part of Arduino - http://www.arduino.cc/
+
+  Copyright (c) 2020 Arduino SA
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General
+  Public License along with this library; if not, write to the
+  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+  Boston, MA  02111-1307  USA
+*/
+
+#ifdef ARDUINO_GIGA
+
+#include "PDM.h"
+#include "mbed.h"
+extern "C" {
+  #include "audio.h"
+}
+
+extern "C" uint16_t *g_pcmbuf;
+static PDMClass *_instance = NULL;
+
+PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
+  _dinPin(dinPin),
+  _clkPin(clkPin),
+  _pwrPin(pwrPin),
+  _onReceive(NULL),
+  _gain(-1),
+  _channels(-1),
+  _samplerate(-1),
+  _init(-1)
+{
+  _instance = this;
+}
+
+PDMClass::~PDMClass()
+{
+  _instance = NULL;
+}
+
+int PDMClass::begin(int channels, int sampleRate) {
+  if(_instance != this) {
+    return 0;
+  }
+
+  _channels = channels;
+  _samplerate = sampleRate;
+
+  if (_gain == -1) {
+    _gain = 3;
+  }
+
+  g_pcmbuf = (uint16_t*)_doubleBuffer.data();
+  _doubleBuffer.swap(0);
+
+  if(py_audio_init(channels, sampleRate)) {
+    if (py_audio_start_streaming()) {
+      _init = 1;
+      return 1;
+    }
+  }
+  return 0;
+}
+
+void PDMClass::end()
+{
+  py_audio_stop_streaming();
+  py_audio_deinit();
+}
+
+int PDMClass::available()
+{
+  size_t avail = _doubleBuffer.available();
+  return avail;
+}
+
+int PDMClass::read(void* buffer, size_t size)
+{
+  int read = _doubleBuffer.read(buffer, size);
+  return read;
+}
+
+void PDMClass::onReceive(void(*function)(void))
+{
+  _onReceive = function;
+  if(_instance != this) {
+    _instance = this;
+  }
+}
+
+void PDMClass::setGain(int gain)
+{
+  _gain = gain;
+  py_audio_gain_set(gain);
+}
+
+void PDMClass::setBufferSize(int bufferSize)
+{
+  _doubleBuffer.setSize(bufferSize);
+}
+
+size_t PDMClass::getBufferSize()
+{
+  return _doubleBuffer.getSize();
+}
+
+#define HALF_TRANSFER_SIZE  (256*_channels)
+static int g_pcmbuf_size=0;
+
+void PDMClass::IrqHandler(bool halftranfer)
+{
+  if (g_pcmbuf_size < _doubleBuffer.getSize()) {
+    audio_pendsv_callback();
+    g_pcmbuf += (HALF_TRANSFER_SIZE);
+    g_pcmbuf_size += HALF_TRANSFER_SIZE*2;
+
+    if(g_pcmbuf_size == _doubleBuffer.getSize()) {
+      _doubleBuffer.swap(g_pcmbuf_size);
+      g_pcmbuf = (uint16_t*)_doubleBuffer.data();
+      g_pcmbuf_size = 0;
+      if (_onReceive) {
+        _onReceive();
+      }
+    }
+  }
+}
+
+extern "C" {
+void PDMIrqHandler(bool halftranfer)
+{
+  _instance->IrqHandler(halftranfer);
+}
+
+void PDMsetBufferSize(int size) {
+  _instance->setBufferSize(size);
+}
+
+size_t PDMgetBufferSize() {
+  return _instance->getBufferSize();
+}
+}
+
+PDMClass PDM(0, 0, 0);
+
+#endif