fix pdm issue with #352

- also add define for PIN_PDM_DIN, PIN_PDM_CLK, PIN_PDM_PWR
- add PDM setPins() for custom board

Author: hathach

libraries/PDM/examples/PDMSerialPlotter/PDMSerialPlotter.ino

@@ -10,10 +10,6 @@
 
 #include <PDM.h>
 
-// The default Circuit Playground Bluefruit pins 
-// data pin, clock pin, power pin (-1 if not used)
-PDMClass PDM(24, 25, -1);
-
 // buffer to read samples into, each sample is 16-bits
 short sampleBuffer[256];
 
@@ -41,8 +37,6 @@ void setup() {
 
 void loop() {
   // wait for samples to be read
-  PDM.IrqHandler();
-
   if (samplesRead) {
     // print samples to the serial monitor or plotter
     for (int i = 0; i < samplesRead; i++) {
@@ -62,4 +56,5 @@ void onPDMdata() {
 
   // 16-bit, 2 bytes per sample
   samplesRead = bytesAvailable / 2;
-}
+}
+

libraries/PDM/src/PDM.cpp

@@ -44,23 +44,35 @@ PDMClass::~PDMClass()
 {
 }
 
+void PDMClass::setPins(int dataPin, int clkPin, int pwrPin)
+{
+  _dinPin = dataPin;
+  _clkPin = clkPin;
+  _pwrPin = pwrPin;
+}
+
 int PDMClass::begin(int channels, long sampleRate)
 {
   _channels = channels;
 
-  /*
+  // Enable high frequency oscillator if not already enabled
+  if (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) {
+    NRF_CLOCK->TASKS_HFCLKSTART    = 1;
+    while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) { }
+  }
+
   // configure the sample rate and channels
   switch (sampleRate) {
     case 16000:
-      nrf_pdm_clock_set(NRF_PDM_FREQ_1032K);
+      NRF_PDM->RATIO = ((PDM_RATIO_RATIO_Ratio80 << PDM_RATIO_RATIO_Pos) & PDM_RATIO_RATIO_Msk);
+      nrf_pdm_clock_set(NRF_PDM_FREQ_1280K);
       break;
     case 41667:
       nrf_pdm_clock_set(NRF_PDM_FREQ_2667K);
       break;
     default:
       return 0; // unsupported
   }
-  */
 
   switch (channels) {
     case 2:
@@ -74,6 +86,7 @@ int PDMClass::begin(int channels, long sampleRate)
     default:
       return 0; // unsupported
   }
+
   setGain(DEFAULT_PDM_GAIN);  
 
   // configure the I/O and mux
@@ -82,8 +95,6 @@ int PDMClass::begin(int channels, long sampleRate)
 
   pinMode(_dinPin, INPUT);
 
-  Serial.printf("Clock P %d Data P %d\n", digitalPinToPinName(_clkPin), digitalPinToPinName(_dinPin));
-
   nrf_pdm_psel_connect(digitalPinToPinName(_clkPin), digitalPinToPinName(_dinPin));
 
   // clear events and enable PDM interrupts
@@ -98,14 +109,13 @@ int PDMClass::begin(int channels, long sampleRate)
     digitalWrite(_pwrPin, HIGH);
   }
 
-
   // clear the buffer
   _doubleBuffer.reset();
+
   // set the PDM IRQ priority and enable
   NVIC_SetPriority(PDM_IRQn, PDM_IRQ_PRIORITY);
   NVIC_ClearPendingIRQ(PDM_IRQn);
   NVIC_EnableIRQ(PDM_IRQn);
-  
 
   // set the buffer for transfer
   // nrf_pdm_buffer_set((uint32_t*)_doubleBuffer.data(), _doubleBuffer.availableForWrite() / (sizeof(int16_t) * _channels));
@@ -116,7 +126,6 @@ int PDMClass::begin(int channels, long sampleRate)
   nrf_pdm_event_clear(NRF_PDM_EVENT_STARTED);
   nrf_pdm_task_trigger(NRF_PDM_TASK_START);
 
-
   return 1;
 }
 
@@ -133,6 +142,8 @@ void PDMClass::end()
     pinMode(_pwrPin, INPUT);
   }
 
+  // Don't disable high frequency oscillator since it could be in use by RADIO
+
   // unconfigure the I/O and un-mux
   nrf_pdm_psel_disconnect();
 
@@ -145,7 +156,7 @@ int PDMClass::available()
 
   size_t avail = _doubleBuffer.available();
 
-  //NVIC_EnableIRQ(PDM_IRQn);
+  NVIC_EnableIRQ(PDM_IRQn);
 
   return avail;
 }
@@ -156,7 +167,7 @@ int PDMClass::read(void* buffer, size_t size)
 
   int read = _doubleBuffer.read(buffer, size);
 
-  //NVIC_EnableIRQ(PDM_IRQn);
+  NVIC_EnableIRQ(PDM_IRQn);
 
   return read;
 }
@@ -203,13 +214,24 @@ void PDMClass::IrqHandler()
   }
 }
 
-extern "C" {
-  void PDM_IRQHandler(void);
-}
-
-void PDM_IRQHandler(void)
+extern "C"
 {
-  PDM.IrqHandler();
+  void PDM_IRQHandler(void)
+  {
+    PDM.IrqHandler();
+  }
 }
 
-extern PDMClass PDM;
+#ifndef PIN_PDM_DIN
+#define PIN_PDM_DIN -1
+#endif
+
+#ifndef PIN_PDM_CLK
+#define PIN_PDM_CLK -1
+#endif
+
+#ifndef PIN_PDM_PWR
+#define PIN_PDM_PWR -1
+#endif
+
+PDMClass PDM(PIN_PDM_DIN, PIN_PDM_CLK, PIN_PDM_PWR);

libraries/PDM/src/PDM.h

@@ -33,6 +33,7 @@ class PDMClass
   PDMClass(int dataPin, int clkPin, int pwrPin);
   virtual ~PDMClass();
 
+  void setPins(int dataPin, int clkPin, int pwrPin);
   int begin(int channels, long sampleRate);
   void end();
 

variants/circuitplayground_nrf52840/variant.h

@@ -54,8 +54,8 @@ extern "C"
 #define LED_STATE_ON         1         // State when LED is litted
 
 // Buttons
-#define PIN_BUTTON1             (4)
-#define PIN_BUTTON2             (5)
+#define PIN_BUTTON1          (4)
+#define PIN_BUTTON2          (5)
 
 // Microphone
 #define PIN_PDM_DIN           24
@@ -120,7 +120,9 @@ static const uint8_t SCK  = PIN_SPI_SCK ;
 #define PIN_WIRE1_SDA       (28)
 #define PIN_WIRE1_SCL       (26)
 
-// QSPI Pins
+/*
+ * QSPI Interfaces
+ */
 #define PIN_QSPI_SCK         29
 #define PIN_QSPI_CS          30
 #define PIN_QSPI_IO0         31
@@ -134,6 +136,13 @@ static const uint8_t SCK  = PIN_SPI_SCK ;
 #define USB_MSC_BLOCK_SIZE    512
 #define USB_MSC_BLOCK_COUNT   ((2*1024*1024) / USB_MSC_BLOCK_SIZE)
 
+/*
+ * PDM Interfaces
+ */
+#define PIN_PDM_DIN         24
+#define PIN_PDM_CLK         25
+#define PIN_PDM_PWR         -1 // not used
+
 #ifdef __cplusplus
 }
 #endif