Add example for NRF52

examples/NRF52_PDM_PWMTest/NRF52_PDM_PWMTest.ino

@@ -0,0 +1,23 @@
+#include <AutoAnalogAudio.h>
+AutoAnalog aaAudio;
+
+// REQUIRES MBed Enabled Core for NRF52 (XIAO 52840 Sense)
+
+void setup() {
+
+  //Startup the PDM Microphone on pin A0 and PWM(pseudo DAC) on pin 5
+  aaAudio.begin(1, 1);
+  aaAudio.autoAdjust = 0;
+  aaAudio.adcBitsPerSample = 16; // 16-bit audio at 16khz is the default on NRF52 and cannot be modified currently (in progress)
+  aaAudio.setSampleRate(16000);
+
+}
+
+void loop() {
+
+  aaAudio.getADC(320); // Get 320 Samples from the ADC
+  for (int i = 0; i < 320; i++) {  // Copy them into the DAC Buffer and change from signed to unsigned ( + 0x8000)
+    aaAudio.dacBuffer16[i] = (uint16_t)(aaAudio.adcBuffer16[i] + 0x8000);
+  }
+  aaAudio.feedDAC(320); // Feed the DAC with the ADC data
+}

src/AutoAnalogAudio.h

@@ -418,6 +418,16 @@ class AutoAnalog
  * for playback on any PC or audio device.
  */
 
+/**
+ * @example NRF52_PDM_PWMTest.ino
+ * <b>For Arduino XIAO 52840 Sense</b><br>
+ *
+ * Recording (pin A0) and playback (pin 5)
+ *
+ * This example demonstrates recording and playback on a single device
+ * using PDM microphone and PWM output
+ */
+
 /**
  * @mainpage Automatic Analog Audio Library for Arduino
  *