Add PassThroughQuad example

examples/HardwareTesting/PassThroughQuad/PassThroughQuad.ino

+/*
+ * A simple hardware test which receives audio from the audio shield
+ * Line-In pins and send it to the Line-Out pins and headphone jack.
+ *
+ * Four audio channels are used.
+ *
+ * This example code is in the public domain.
+ */
+
+#include <Audio.h>
+#include <Wire.h>
+#include <SPI.h>
+#include <SD.h>
+#include <SerialFlash.h>
+
+// GUItool: begin automatically generated code
+AudioInputI2SQuad        i2s_quad1;      //xy=150,69
+AudioOutputI2SQuad       i2s_quad2;      //xy=365,94
+AudioConnection          patchCord1(i2s_quad1, 0, i2s_quad2, 2);
+AudioConnection          patchCord2(i2s_quad1, 1, i2s_quad2, 3);
+AudioConnection          patchCord3(i2s_quad1, 2, i2s_quad2, 0);
+AudioConnection          patchCord4(i2s_quad1, 3, i2s_quad2, 1);
+AudioControlSGTL5000     sgtl5000_1;     //xy=302,184
+AudioControlSGTL5000     sgtl5000_2;     //xy=302,254
+// GUItool: end automatically generated code
+
+
+const int myInput = AUDIO_INPUT_LINEIN;
+//const int myInput = AUDIO_INPUT_MIC;
+
+
+void setup() {
+  // Audio connections require memory to work.  For more
+  // detailed information, see the MemoryAndCpuUsage example
+  AudioMemory(12);
+
+  // Enable the first audio shield, select input, and enable output
+  sgtl5000_1.setAddress(LOW);
+  sgtl5000_1.enable();
+  sgtl5000_1.inputSelect(myInput);
+  sgtl5000_1.volume(0.5);
+
+  // Enable the second audio shield, select input, and enable output
+  sgtl5000_2.setAddress(HIGH);
+  sgtl5000_2.enable();
+  sgtl5000_2.inputSelect(myInput);
+  sgtl5000_2.volume(0.5);
+}
+
+void loop() {
+}
+
+