Add I2S support

cores/arduino/wiring.c

@@ -65,6 +65,7 @@ void init( void )
     // Capture error
     while ( 1 ) ;
   }
+  NVIC_SetPriority (SysTick_IRQn,  (1 << __NVIC_PRIO_BITS) - 2);  /* set Priority for Systick Interrupt (2nd lowest) */
 
   // Clock PORT for Digital I/O
 //	PM->APBBMASK.reg |= PM_APBBMASK_PORT ;

libraries/I2S/examples/InputSerialPlotter/InputSerialPlotter.ino

@@ -0,0 +1,46 @@
+/*
+ This example reads audio data from an Invensense's ICS43432 I2S microphone
+ breakout board, and prints out the samples to the Serial console. The
+ Serial Plotter built into the Arduino IDE can be used to plot the audio
+ data (Tools -> Serial Plotter)
+
+ Circuit:
+ * Arduino/Genuino Zero or MKR1000 board
+ * ICS43432:
+   * GND connected GND
+   * 3.3V connected 3.3V
+   * WS connected to pin 0 (Zero) or pin 3 (MKR1000)
+   * CLK connected to pin 1 (Zero) or pin 2 (MKR1000)
+   * SD connected to pin 9 (Zero) or pin A6 (MKR1000)
+
+ created 17 November 2016
+ by Sandeep Mistry
+ */
+
+#include <I2S.h>
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  // A baud rate of 115200 is used instead of 9600 for a faster data rate
+  // on non-native USB ports
+  Serial.begin(115200);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB port only
+  }
+
+  // start I2S at 8 kHz with 32-bits per sample
+  if (I2S.begin(I2S_PHILIPS_MODE, 8000, 32)) {
+    Serial.println("Failed to initialize I2S!");
+    while (1); // do nothing
+  }
+}
+
+void loop() {
+  // read a sample
+  int sample = I2S.read();
+
+  if (sample) {
+    // if it's non-zero print value to serial
+    Serial.println(sample);
+  }
+}

libraries/I2S/examples/SimpleTone/SimpleTone.ino

@@ -0,0 +1,53 @@
+/*
+ This example generates a square wave based tone at a specified frequency
+ and sample rate. Then outputs the data using the I2S interface to a
+ MAX08357 I2S Amp Breakout board.
+
+ Circuit:
+ * Arduino/Genuino Zero or MKR1000 board
+ * MAX08357:
+   * GND connected GND
+   * VIN connected 5V
+   * LRC connected to pin 0 (Zero) or pin 3 (MKR1000)
+   * BCLK connected to pin 1 (Zero) or pin 2 (MKR1000)
+   * DIN connected to pin 9 (Zero) or pin A6 (MKR1000)
+
+ created 17 November 2016
+ by Sandeep Mistry
+ */
+
+#include <I2S.h>
+
+const int frequency = 440; // frequency of square wave in Hz
+const int amplitude = 500; // amplitude of square wave
+const int sampleRate = 8000; // sample rate in Hz
+
+const int halfWavelength = (sampleRate / frequency); // half wavelength of square wave
+
+short sample = amplitude; // current sample value
+int count = 0;
+
+void setup() {
+  Serial.begin(9600);
+  Serial.println("I2S simple tone");
+
+  // start I2S at the sample rate with 16-bits per sample
+  if (I2S.begin(I2S_PHILIPS_MODE, sampleRate, 16)) {
+    Serial.println("Failed to initialize I2S!");
+    while (1); // do nothing
+  }
+}
+
+void loop() {
+  if (count % halfWavelength == 0) {
+    // invert the sample every half wavelength count multiple to generate square wave
+    sample = -1 * sample;
+  }
+
+  // write the same sample twice, once for left and once for the right channel
+  I2S.write(sample);
+  I2S.write(sample);
+
+  // increment the counter for the next sample
+  count++;
+}

libraries/I2S/keywords.txt

@@ -0,0 +1,25 @@
+#######################################
+# Syntax Coloring Map I2S
+#######################################
+
+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+
+I2S	KEYWORD1
+
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+begin			KEYWORD2
+end				KEYWORD2
+
+onReceive		KEYWORD2
+onTransmit		KEYWORD2
+
+#######################################
+# Constants (LITERAL1)
+#######################################
+I2S_PHILIPS_MODE			LITERAL1
+I2S_RIGHT_JUSTIFIED_MODE	LITERAL1
+I2S_LEFT_JUSTIFIED_MODE		LITERAL1

libraries/I2S/library.properties

@@ -0,0 +1,9 @@
+name=I2S
+version=1.0
+author=Arduino
+maintainer=Arduino <[email protected]>
+sentence=Enables the communication with devices that use the Inter-IC Sound (I2S) Bus. Specific implementation for Arduino Zero.
+paragraph=
+category=Communication
+url=http://www.arduino.cc/en/Reference/I2S
+architectures=samd