add support for left and right justified modes

Author: sandeepmistry

libraries/I2S/src/I2S.cpp

@@ -63,6 +63,8 @@ int I2SClass::begin(int mode, long sampleRate, int bitsPerSample, bool driveCloc
 
   switch (mode) {
     case I2S_PHILIPS_MODE:
+    case I2S_RIGHT_JUSTIFIED_MODE:
+    case I2S_LEFT_JUSTIFIED_MODE:
       break;
 
     default:
@@ -109,18 +111,26 @@ int I2SClass::begin(int mode, long sampleRate, int bitsPerSample, bool driveCloc
   }
 
   i2sd.disable();
-  i2sd.set1BitDelay(_deviceIndex);
+
+  if (mode == I2S_PHILIPS_MODE) {
+    i2sd.set1BitDelay(_deviceIndex);
+  } else {
+    i2sd.set0BitDelay(_deviceIndex);
+  }
   i2sd.setNumberOfSlots(_deviceIndex, 1);
   i2sd.setSlotSize(_deviceIndex, bitsPerSample);
 
   pinPeripheral(_sckPin, PIO_COM);
   pinPeripheral(_fsPin, PIO_COM);
 
-  i2sd.setSlotAdjustedLeft(_deviceIndex);
-  if (driveClock) {
-    i2sd.setClockUnit(_deviceIndex);
+  if (mode == I2S_RIGHT_JUSTIFIED_MODE) {
+    i2sd.setSlotAdjustedRight(_deviceIndex);
+  } else {
+    i2sd.setSlotAdjustedLeft(_deviceIndex);
   }
 
+  i2sd.setClockUnit(_deviceIndex);
+
   pinPeripheral(_sdPin, PIO_COM);
 
   i2sd.enable();

libraries/I2S/src/I2S.h

@@ -24,7 +24,9 @@
 #include "utility/I2SDoubleBuffer.h"
 
 typedef enum {
-  I2S_PHILIPS_MODE
+  I2S_PHILIPS_MODE,
+  I2S_RIGHT_JUSTIFIED_MODE,
+  I2S_LEFT_JUSTIFIED_MODE
 } i2s_mode_t;
 
 class I2SClass : public Stream

libraries/I2S/src/utility/SAMD21_I2SDevice.h

@@ -63,6 +63,10 @@ class I2SDevice_SAMD21G18x {
     i2s.CLKCTRL[index].bit.FSSEL = I2S_CLKCTRL_FSSEL_FSPIN_Val;
   }
 
+  inline void set0BitDelay(int index) {
+    i2s.CLKCTRL[index].bit.BITDELAY = I2S_CLKCTRL_BITDELAY_LJ_Val;
+  }
+
   inline void set1BitDelay(int index) {
     i2s.CLKCTRL[index].bit.BITDELAY = I2S_CLKCTRL_BITDELAY_I2S_Val;
   }
@@ -95,6 +99,10 @@ class I2SDevice_SAMD21G18x {
     }
   }
 
+  inline void setSlotAdjustedRight(int index) {
+    i2s.SERCTRL[index].bit.SLOTADJ = I2S_SERCTRL_SLOTADJ_RIGHT_Val;
+  }
+
   inline void setSlotAdjustedLeft(int index) {
     i2s.SERCTRL[index].bit.SLOTADJ = I2S_SERCTRL_SLOTADJ_LEFT_Val;
   }