Improve sketches of CurieI2S library

libraries/CurieI2S/examples/I2SDMA_RXCallBack/I2SDMA_RXCallBack.ino

@@ -37,8 +37,8 @@ uint32_t loop_count = 0; // record the higher 16 bits of received data
 uint32_t shift_count = 0; // the position of first non-zero
 void setup() 
 {
-  Serial.begin(115200);
-  while(!Serial);
+  Serial.begin(115200); // initialize Serial communication
+  while(!Serial) ;      // wait for serial port to connect.
   Serial.println("CurieI2SDMA Rx Callback");
 
   CurieI2SDMA.iniRX();
@@ -119,4 +119,4 @@ void loop()
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-
   1301 USA
-*/
+*/

libraries/CurieI2S/examples/I2SDMA_TXCallBack/I2SDMA_TXCallBack.ino

@@ -15,8 +15,8 @@ uint32_t dataBuff[BUFF_SIZE];
 uint32_t loop_count = 0;
 void setup() 
 {
-  Serial.begin(115200);
-  while(!Serial);
+  Serial.begin(115200); // initialize Serial communication
+  while(!Serial) ;      // wait for serial port to connect.
   Serial.println("CurieI2SDMA Tx Callback");
 
   CurieI2SDMA.iniTX();

libraries/CurieI2S/examples/I2S_RxCallback/I2S_RxCallback.ino

@@ -23,8 +23,8 @@ volatile int count = 0;
 void setup() 
 {
   // put your setup code here, to run once:
-  Serial.begin(115200);
-  while(!Serial);
+  Serial.begin(115200); // initialize Serial communication
+  while(!Serial) ;      // wait for serial port to connect.
   Serial.println("CurieI2S Rx Callback Example");
   CurieI2S.begin(I2S_44K, I2S_32bit);
   CurieI2S.setI2SMode(PHILIPS_MODE);

libraries/CurieI2S/examples/I2S_TxCallback/I2S_TxCallback.ino

@@ -6,8 +6,8 @@
 
 void setup() 
 {
-  Serial.begin(115200);
-  while(!Serial);
+  Serial.begin(115200); // initialize Serial communication
+  while(!Serial) ;      // wait for serial port to connect.
   Serial.println("CurieI2S Tx Callback");
   CurieI2S.begin(I2S_44K, I2S_32bit);
   CurieI2S.setI2SMode(PHILIPS_MODE);