Add functions to set PDM pins, remove unused pwrPin (#2133)

* functions to set PDM pins

* change pin set method to better match existing libs

Author: clhuang

libraries/PDM/src/PDM.h

@@ -25,9 +25,11 @@
 
 class PDMClass {
 public:
-    PDMClass(int dinPin, int clkPin, int pwrPin);
+    PDMClass(int dinPin, int clkPin);
     virtual ~PDMClass();
 
+    void setDIN(int dinPin);
+    void setCLK(int clkPin);
     int begin(int channels, int sampleRate);
     void end();
 
@@ -49,7 +51,6 @@ class PDMClass {
 private:
     int _dinPin;
     int _clkPin;
-    int _pwrPin;
 
     int _channels;
     int _samplerate;
@@ -70,6 +71,4 @@ class PDMClass {
     void (*_onReceive)(void);
 };
 
-#ifdef PIN_PDM_DIN
 extern PDMClass PDM;
-#endif

libraries/PDM/src/rp2040/PDM.cpp

@@ -36,10 +36,9 @@ extern "C" {
 }
 
 
-PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
+PDMClass::PDMClass(int dinPin, int clkPin) :
     _dinPin(dinPin),
     _clkPin(clkPin),
-    _pwrPin(pwrPin),
     _onReceive(NULL),
     _gain(-1),
     _channels(-1),
@@ -55,13 +54,26 @@ PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
 PDMClass::~PDMClass() {
 }
 
+void PDMClass::setCLK(int clkPin) {
+    _clkPin = clkPin;
+}
+
+void PDMClass::setDIN(int dinPin) {
+    _dinPin = dinPin;
+}
+
 int PDMClass::begin(int channels, int sampleRate) {
 
     if (_init == 1) {
         //ERROR: please call end first
         return 0;
     }
 
+    if (_dinPin == -1 || _clkPin == -1) {
+        //ERROR: please call setDIN/setCLK first
+        return 0;
+    }
+
     //_channels = channels; // only one channel available
 
     // clear the final buffers
@@ -228,8 +240,14 @@ void PDMClass::IrqHandler(bool halftranfer) {
         _onReceive();
     }
 }
-#ifdef PIN_PDM_DIN
-PDMClass PDM(PIN_PDM_DIN, PIN_PDM_CLK, -1);
+#ifndef PIN_PDM_DIN
+#define PIN_PDM_DIN -1
 #endif // PIN_PDM_DIN
+//
+#ifndef PIN_PDM_CLK
+#define PIN_PDM_CLK -1
+#endif // PIN_PDM_CLK
+
+PDMClass PDM(PIN_PDM_DIN, PIN_PDM_CLK);