update to 1.0.3

* Fix the bug that read cannot get the right result.
* Add USB support
* Add more example.

DFRobotDFPlayerMini.cpp

@@ -7,7 +7,7 @@
  * @copyright	GNU Lesser General Public License
  *
  * @author [Angelo](Angelo.qiao@dfrobot.com)
- * @version  V1.0
+ * @version  V1.0.3
  * @date  2016-12-07
  */
 
@@ -31,15 +31,12 @@ uint16_t DFRobotDFPlayerMini::calculateCheckSum(uint8_t *buffer){
 }
 
 void DFRobotDFPlayerMini::sendStack(){
-  if (_sending[Stack_ACK]) {
+  if (_sending[Stack_ACK]) {  //if the ack mode is on wait until the last transmition
     while (_isSending) {
       delay(0);
       available();
     }
   }
-  else{
-    delay(10);
-  }
 
 #ifdef _DEBUG
   Serial.println();
@@ -53,6 +50,10 @@ void DFRobotDFPlayerMini::sendStack(){
   _serial->write(_sending, DFPLAYER_SEND_LENGTH);
   _timeOutTimer = millis();
   _isSending = _sending[Stack_ACK];
+  
+  if (!_sending[Stack_ACK]) { //if the ack mode is off wait 10 ms after one transmition.
+    delay(10);
+  }
 }
 
 void DFRobotDFPlayerMini::sendStack(uint8_t command){
@@ -80,15 +81,23 @@ void DFRobotDFPlayerMini::disableACK(){
   _sending[Stack_ACK] = 0x00;
 }
 
-bool DFRobotDFPlayerMini::waitAvailable(){
-  _isSending = true;
+bool DFRobotDFPlayerMini::waitAvailable(unsigned long duration){
+  unsigned long timer = millis();
+  if (!duration) {
+    duration = _timeOutDuration;
+  }
   while (!available()){
+    if (millis() - timer > duration) {
+      return false;
+    }
     delay(0);
   }
-  return _handleType != TimeOut;
+  return true;
 }
 
 bool DFRobotDFPlayerMini::begin(Stream &stream, bool isACK, bool doReset){
+  _serial = &stream;
+  
   if (isACK) {
     enableACK();
   }
@@ -96,20 +105,17 @@ bool DFRobotDFPlayerMini::begin(Stream &stream, bool isACK, bool doReset){
     disableACK();
   }
   
-  _serial = &stream;
-
   if (doReset) {
-    _timeOutDuration += 3000;
     reset();
-    waitAvailable();
-    _timeOutDuration -= 3000;
+    waitAvailable(2000);
     delay(200);
-  } else {
+  }
+  else {
     // assume same state as with reset(): online
     _handleType = DFPlayerCardOnline;
   }
 
-  return (readType() == DFPlayerCardOnline) || !isACK;
+  return (readType() == DFPlayerCardOnline) || (readType() == DFPlayerUSBOnline) || !isACK;
 }
 
 uint8_t DFRobotDFPlayerMini::readType(){
@@ -142,7 +148,13 @@ uint8_t DFRobotDFPlayerMini::readCommand(){
 }
 
 void DFRobotDFPlayerMini::parseStack(){
-  _handleCommand = *(_received + Stack_Command);
+  uint8_t handleCommand = *(_received + Stack_Command);
+  if (handleCommand == 0x41) { //handle the 0x41 ack feedback as a spcecial case, in case the pollusion of _handleCommand, _handleParameter, and _handleType.
+    _isSending = false;
+    return;
+  }
+  
+  _handleCommand = handleCommand;
   _handleParameter =  arrayToUint16(_received + Stack_Parameter);
 
   switch (_handleCommand) {
@@ -150,26 +162,35 @@ void DFRobotDFPlayerMini::parseStack(){
       handleMessage(DFPlayerPlayFinished, _handleParameter);
       break;
     case 0x3F:
-      if (_handleParameter & 0x02) {
+      if (_handleParameter & 0x01) {
+        handleMessage(DFPlayerUSBOnline, _handleParameter);
+      }
+      else if (_handleParameter & 0x02) {
         handleMessage(DFPlayerCardOnline, _handleParameter);
       }
+      else if (_handleParameter & 0x03) {
+        handleMessage(DFPlayerCardUSBOnline, _handleParameter);
+      }
       break;
     case 0x3A:
-      if (_handleParameter & 0x02) {
+      if (_handleParameter & 0x01) {
+        handleMessage(DFPlayerUSBInserted, _handleParameter);
+      }
+      else if (_handleParameter & 0x02) {
         handleMessage(DFPlayerCardInserted, _handleParameter);
       }
       break;
     case 0x3B:
-      if (_handleParameter & 0x02) {
+      if (_handleParameter & 0x01) {
+        handleMessage(DFPlayerUSBRemoved, _handleParameter);
+      }
+      else if (_handleParameter & 0x02) {
         handleMessage(DFPlayerCardRemoved, _handleParameter);
       }
       break;
     case 0x40:
       handleMessage(DFPlayerError, _handleParameter);
       break;
-    case 0x41:
-      _isSending = false;
-      break;
     case 0x3C:
     case 0x3E:
     case 0x42:
@@ -185,7 +206,7 @@ void DFRobotDFPlayerMini::parseStack(){
     case 0x4D:
     case 0x4E:
     case 0x4F:
-      _isAvailable = true;
+      handleMessage(DFPlayerFeedBack, _handleParameter);
       break;
     default:
       handleError(WrongStack);
@@ -215,7 +236,6 @@ bool DFRobotDFPlayerMini::available(){
       Serial.print(F(" "));
 #endif
       if (_received[Stack_Header] == 0x7E) {
-        _isAvailable = false;
         _receivedIndex ++;
       }
     }
@@ -247,9 +267,6 @@ bool DFRobotDFPlayerMini::available(){
             if (validateStack()) {
               _receivedIndex = 0;
               parseStack();
-              if (_isAvailable && !_sending[Stack_ACK]) {
-                _isSending = false;
-              }
               return _isAvailable;
             }
             else{
@@ -387,7 +404,12 @@ void DFRobotDFPlayerMini::disableDAC(){
 int DFRobotDFPlayerMini::readState(){
   sendStack(0x42);
   if (waitAvailable()) {
-    return read();
+    if (readType() == DFPlayerFeedBack) {
+      return read();
+    }
+    else{
+      return -1;
+    }
   }
   else{
     return -1;
@@ -404,10 +426,15 @@ int DFRobotDFPlayerMini::readVolume(){
   }
 }
 
-uint8_t DFRobotDFPlayerMini::readEQ(){
+int DFRobotDFPlayerMini::readEQ(){
   sendStack(0x44);
   if (waitAvailable()) {
-    return read();
+    if (readType() == DFPlayerFeedBack) {
+      return read();
+    }
+    else{
+      return -1;
+    }
   }
   else{
     return -1;
@@ -430,7 +457,12 @@ int DFRobotDFPlayerMini::readFileCounts(uint8_t device){
   }
   
   if (waitAvailable()) {
-    return read();
+    if (readType() == DFPlayerFeedBack) {
+      return read();
+    }
+    else{
+      return -1;
+    }
   }
   else{
     return -1;
@@ -452,7 +484,12 @@ int DFRobotDFPlayerMini::readCurrentFileNumber(uint8_t device){
       break;
   }
   if (waitAvailable()) {
-    return read();
+    if (readType() == DFPlayerFeedBack) {
+      return read();
+    }
+    else{
+      return -1;
+    }
   }
   else{
     return -1;
@@ -462,7 +499,12 @@ int DFRobotDFPlayerMini::readCurrentFileNumber(uint8_t device){
 int DFRobotDFPlayerMini::readFileCountsInFolder(int folderNumber){
   sendStack(0x4E, folderNumber);
   if (waitAvailable()) {
-    return read();
+    if (readType() == DFPlayerFeedBack) {
+      return read();
+    }
+    else{
+      return -1;
+    }
   }
   else{
     return -1;
@@ -472,7 +514,12 @@ int DFRobotDFPlayerMini::readFileCountsInFolder(int folderNumber){
 int DFRobotDFPlayerMini::readFolderCounts(){
   sendStack(0x4F);
   if (waitAvailable()) {
-    return read();
+    if (readType() == DFPlayerFeedBack) {
+      return read();
+    }
+    else{
+      return -1;
+    }
   }
   else{
     return -1;