Fixed PDM::Begin return value

Author: pennam

libraries/PDM/src/stm32/PDM.cpp

@@ -71,11 +71,11 @@ int PDMClass::begin(int channels, long sampleRate) {
 
   //g_pcmbuf = (uint16_t*)_doubleBuffer.data();
 
-  py_audio_init(channels, sampleRate, gain_db, 0.9883f);
-
-  py_audio_start_streaming();
-
-  return 1;
+  if(py_audio_init(channels, sampleRate, gain_db, 0.9883f)) {
+    py_audio_start_streaming();
+    return 1;
+  }
+  return 0;
 }
 
 void PDMClass::end()
@@ -139,4 +139,4 @@ void PDMsetBufferSize(int size) {
 
 PDMClass PDM(0, 0, 0);
 
-#endif
+#endif