Set default microphone samplerate by a CONFIG option

Author: finneyj

inc/MicroBitAudio.h

@@ -49,6 +49,10 @@ DEALINGS IN THE SOFTWARE.
 #define CONFIG_AUDIO_INPUT_CHANNELS                       4
 #endif
 
+#ifndef CONFIG_AUDIO_DEFAULT_MICROPHONE_SAMPLERATE
+#define CONFIG_AUDIO_DEFAULT_MICROPHONE_SAMPLERATE        11000
+#endif
+
 namespace codal
 {
     /**

source/MicroBitAudio.cpp

@@ -61,7 +61,7 @@ MicroBitAudio::MicroBitAudio(NRF52Pin &pin, NRF52Pin &speaker, NRF52ADC &adc, NR
     synth.allowEmptyBuffers(true);
 
     mic = adc.getChannel(microphone, false);
-    mic->setSampleRate(11000);
+    mic->setSampleRate(CONFIG_AUDIO_DEFAULT_MICROPHONE_SAMPLERATE);
     mic->setGain(7, 0);
 
     activateMic();