Add example of using TDM hardware

Based around the CS42448, but should port to any
other part, provided it's expecting 32-bit data,
by changing the control object and setup() code

examples/TestCS42448_F32/TestCS42448_F32.ino

@@ -0,0 +1,117 @@
+/*
+ * Very basic demo of 24-bit TDM I/O, using
+ * 6i8o CS42448 board.
+ * 
+ * Suggested wiring is to monitor outputs 
+ * 1, 2, 5 and 6, and connect output 3 to
+ * input 1.
+ * 
+ * Output 3: 441Hz, so input 1 has that at half amplitude.
+ * Output 1: 440Hz sine
+ * Output 2: 440Hz cosine
+ * Output 5: copy of input 1
+ * Output 6: 1x input 1 + 0.5x sine (1Hz beat)
+ * 
+ * Input 1 has an RMS object so you can check it's active.
+ * 
+ * Scope capture has outputs 1+2 in blue and green, 
+ * output 5 in magenta, output 6 in yellow.
+ */
+#include <Audio.h>
+
+//======================================================
+// Integer audio library objects:
+
+// GUItool: begin automatically generated code
+AudioInputTDM            tdmI;           //xy=572,233
+AudioOutputTDM           tdmO;           //xy=708,237
+
+
+AudioControlCS42448      cs42448;        //xy=699,387
+// GUItool: end automatically generated code
+
+//======================================================
+// F32 audio library objects
+#include "OpenAudio_ArduinoLibrary.h"
+#include "AudioStream_F32.h"
+
+const float sample_rate_Hz = 44100.0f ;  
+const int   audio_block_samples = 128;    // Always 128, which is AUDIO_BLOCK_SAMPLES from AudioStream.h
+AudioSettings_F32 audio_settings(sample_rate_Hz, audio_block_samples);
+
+// GUItool: begin automatically generated code
+//AudioInputI2S_F32        dummyI2S;    //xy=302,461 // dummy to allow export
+AudioConvert_I16x2toF32  convert_I16x2toF32_1; //xy=348,511
+AudioAnalyzeRMS_F32      rms;           //xy=548,570
+AudioSynthSineCosine_F32 sine_cos1;      //xy=598,333
+AudioSynthWaveform_F32   wav1;      //xy=605,395
+AudioMixer4_F32          mixer4;       //xy=644,490
+AudioConvert_F32toI16x2  convert_F32toI16x2_1; //xy=812,314
+AudioConvert_F32toI16x2  convert_F32toI16x2_2; //xy=820,352
+AudioConvert_F32toI16x2  convert_F32toI16x2_3; //xy=829,395
+AudioConvert_F32toI16x2  convert_F32toI16x2_5; //xy=852,490
+AudioConvert_F32toI16x2  convert_F32toI16x2_6; //xy=862,540
+AudioConnection_F32          patchCord1(convert_I16x2toF32_1, convert_F32toI16x2_6);
+AudioConnection_F32          patchCord2(convert_I16x2toF32_1, 0, mixer4, 1);
+AudioConnection_F32          patchCord3(convert_I16x2toF32_1, rms);
+AudioConnection_F32          patchCord4(sine_cos1, 0, convert_F32toI16x2_1, 0);
+AudioConnection_F32          patchCord5(sine_cos1, 0, mixer4, 0);
+AudioConnection_F32          patchCord6(sine_cos1, 1, convert_F32toI16x2_2, 0);
+AudioConnection_F32          patchCord7(wav1, convert_F32toI16x2_3);
+AudioConnection_F32          patchCord8(mixer4, convert_F32toI16x2_5);
+// GUItool: end automatically generated code
+
+//======================================================
+// Hand-generated patchcords between libraries
+AudioConnection pc1(tdmI,0, convert_I16x2toF32_1,0);
+AudioConnection pc2(tdmI,1, convert_I16x2toF32_1,1);
+
+AudioConnection  pc3(convert_F32toI16x2_1,0,  tdmO, 0);
+AudioConnection  pc4(convert_F32toI16x2_1,1,  tdmO, 1);
+AudioConnection  pc5(convert_F32toI16x2_2,0,  tdmO, 2);
+AudioConnection  pc6(convert_F32toI16x2_2,1,  tdmO, 3);
+AudioConnection  pc7(convert_F32toI16x2_3,0,  tdmO, 4);
+AudioConnection  pc8(convert_F32toI16x2_3,1,  tdmO, 5);
+// TDM output 4 (ports 6+7) unused
+AudioConnection  pc9(convert_F32toI16x2_5,0,  tdmO, 8);
+AudioConnection pc10(convert_F32toI16x2_5,1,  tdmO, 9);
+AudioConnection pc11(convert_F32toI16x2_6,0,  tdmO,10);
+AudioConnection pc12(convert_F32toI16x2_6,1,  tdmO,11);
+
+//======================================================
+void setup() 
+{
+  AudioMemory(32); // TDM uses many blocks!
+  AudioMemory_F32(20);
+
+  cs42448.enable();
+  cs42448.volume(0.5f);
+  cs42448.inputLevel(0.5f);
+
+  pinMode(LED_BUILTIN,OUTPUT);
+  mixer4.gain(0,0.5);
+  mixer4.gain(1,1.0); // input level is set to 0.5, so boost
+  
+  sine_cos1.amplitude(0.5f); 
+  sine_cos1.frequency(440.0f);
+
+  wav1.begin(0.5f,441.0f,WAVEFORM_SINE);
+
+  // Un-comment for low output high gain test. Note
+  // that the level is extremely low, so there will be
+  // essentially no visible signal on output 5!
+  /*
+  float attenuation = 2000.0f;
+  wav1.begin(1.0f/attenuation,441.0f,WAVEFORM_SINE);
+  mixer4.gain(1,attenuation/2); 
+  //*/
+}
+
+
+void loop() 
+{
+  delay(250);
+  digitalToggle(LED_BUILTIN);
+  if (rms.available())
+    Serial.printf("RMS input level: %.3f\n", rms.read());
+}

keywords.txt

@@ -100,8 +100,9 @@ micBiasEnable	KEYWORD2
 micBiasDisable	KEYWORD2
 
 AudioConvert_I16toF32	KEYWORD1
-
 AudioConvert_F32toI16	KEYWORD1
+AudioConvert_I16x2toF32	KEYWORD1
+AudioConvert_F32toI16x2	KEYWORD1
 
 AudioEffectDelay_OA_F32	KEYWORD1
 delay	KEYWORD2