Unify nRF52 and STM PDM libraries

Author: facchinm

libraries/PDM/src/PDM.h

@@ -21,10 +21,6 @@
 
 #include <Arduino.h>
 
-#if !defined(ARDUINO_ARCH_NRF52840) && !defined(ARDUINO_AS_MBED_LIBRARY)
-#error "This library targets only NRF52840 boards, not every mbed target"
-#endif
-
 #include "utility/PDMDoubleBuffer.h"
 
 class PDMClass
@@ -45,7 +41,7 @@ class PDMClass
   void setBufferSize(int bufferSize);
 
 // private:
-  void IrqHandler();
+  void IrqHandler(bool halftranfer);
 
 private:
   int _dinPin;

libraries/PDM/src/PDM.cpp renamed to libraries/PDM/src/nrf52/PDM.cpp

@@ -21,6 +21,9 @@
 */
 
 #include "PDM.h"
+
+#if defined(ARDUINO_ARCH_NRF52840)
+
 #include <hal/nrf_pdm.h>
 
 #define DEFAULT_PDM_GAIN     20
@@ -180,7 +183,7 @@ void PDMClass::setBufferSize(int bufferSize)
   _doubleBuffer.setSize(bufferSize);
 }
 
-void PDMClass::IrqHandler()
+void PDMClass::IrqHandler(bool halftranfer)
 {
   if (nrf_pdm_event_check(NRF_PDM_EVENT_STARTED)) {
     nrf_pdm_event_clear(NRF_PDM_EVENT_STARTED);
@@ -210,8 +213,10 @@ void PDMClass::IrqHandler()
 extern "C" {
   __attribute__((__used__)) void PDM_IRQHandler_v(void)
   {
-    PDM.IrqHandler();
+    PDM.IrqHandler(true);
   }
 }
 
 PDMClass PDM(PIN_PDM_DIN, PIN_PDM_CLK, PIN_PDM_PWR);
+
+#endif

libraries/PDM/src/stm32/PDM.cpp

@@ -0,0 +1,175 @@
+/*
+  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 TARGET_STM
+
+#include "PDM.h"
+#include "audio.h"
+#include "mbed.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;
+
+PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
+  _dinPin(dinPin),
+  _clkPin(clkPin),
+  _pwrPin(pwrPin),
+  _onReceive(NULL)
+{
+}
+
+PDMClass::~PDMClass()
+{
+}
+
+int PDMClass::begin(int channels, long sampleRate) {
+
+  _channels = channels;
+
+  // fixme: only works in stereo mode
+  channels = 2;
+
+  setBufferSize(AUDIO_IN_PDM_BUFFER_SIZE / 4 * channels);
+
+  if (isBoardRev2()) {
+    mbed::I2C i2c(PB_7, PB_6);
+    char data[2];
+
+    // SW2 to 3.3V (SW2_VOLT)
+    data[0] = 0x3B;
+    data[1] = 0xF;
+    i2c.write(8 << 1, data, sizeof(data));
+
+    // SW1 to 3.0V (SW1_VOLT)
+    data[0] = 0x35;
+    data[1] = 0xF;
+    i2c.write(8 << 1, data, sizeof(data));
+  }
+
+  BSP_AUDIO_IN_SelectInterface(AUDIO_IN_INTERFACE_PDM);
+
+  /* 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;
+  }
+
+  /* Start the record */
+  BSP_AUDIO_IN_Record((uint16_t*)recordPDMBuf, AUDIO_IN_PDM_BUFFER_SIZE * channels);
+  return 1;
+}
+
+void PDMClass::end()
+{
+}
+
+int PDMClass::available()
+{
+  size_t avail = _doubleBuffer.available();
+  if (_channels == 1) {
+    return avail/2;
+  } else {
+    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;
+}
+
+void PDMClass::onReceive(void(*function)(void))
+{
+  _onReceive = function;
+}
+
+void PDMClass::setGain(int gain)
+{
+
+}
+
+void PDMClass::setBufferSize(int bufferSize)
+{
+  _doubleBuffer.setSize(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);
+
+    _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);
+  }
+
+  /**
+      @brief  Manages the DMA Half Transfer complete interrupt.
+      @param  None
+      @retval None
+  */
+  __attribute__((__used__)) void BSP_AUDIO_IN_HalfTransfer_CallBack(void)
+  {
+    PDM.IrqHandler(true);
+  }
+}
+
+PDMClass PDM(0, 0, 0);
+
+#endif