added optional argument pointer

added optional argument pointer, see arduino/ArduinoCore-sam#95 (comment)

Author: gicking

Diff for: cores/arduino/HardwareSerial.cpp

@@ -285,11 +285,12 @@ size_t HardwareSerial::write(uint8_t c)
   return 1;
 }
 
-void HardwareSerial::attachInterrupt_Receive( isrRx_t fn )
+void HardwareSerial::attachInterrupt_Receive( isrRx_t fn, void* args )
 {
   uint8_t oldSREG = SREG;
   cli();
   _isrRx = fn;
+  _rxArg = args;
   SREG = oldSREG;
 }
 

Diff for: cores/arduino/HardwareSerial.h

@@ -119,10 +119,11 @@ class HardwareSerial : public Stream
     unsigned char _tx_buffer[SERIAL_TX_BUFFER_SIZE];
 
     // custom handlers for RX and TXC interrupts 
-    typedef void (* isrRx_t)( uint8_t d, uint8_t s );
+    typedef void (* isrRx_t)( uint8_t data, uint8_t status, void* args );
     typedef void (* isrTx_t)( void );
     isrRx_t  _isrRx;
     isrTx_t  _isrTx;
+    void*    _rxArg;
 
   public:
     inline HardwareSerial(
@@ -151,7 +152,7 @@ class HardwareSerial : public Stream
     inline void _tx_complete_irq(void);
 
     // attach custom handlers for RX and TXC interrupts 
-    void attachInterrupt_Receive( isrRx_t fn );
+    void attachInterrupt_Receive( isrRx_t fn, void *args = NULL );
     void detachInterrupt_Receive( void ) { attachInterrupt_Receive( (isrRx_t) NULL ); };
     void attachInterrupt_Send( isrTx_t fn );
     void detachInterrupt_Send( void );

Diff for: cores/arduino/HardwareSerial_private.h

@@ -95,19 +95,19 @@ HardwareSerial::HardwareSerial(
     _udr(udr),
     _rx_buffer_head(0), _rx_buffer_tail(0),
     _tx_buffer_head(0), _tx_buffer_tail(0),
-    _isrRx(NULL), _isrTx(dummyTxFct)
+    _isrRx(NULL), _isrTx(dummyTxFct), _rxArg(NULL)
 {
 }
 
 // Actual interrupt handlers //////////////////////////////////////////////////////////////
 
 void HardwareSerial::_rx_complete_irq(void)
 {
-  // user receive function was attached -> call it with data and status byte 
+  // user receive function was attached -> call it with data, status byte and optional argument pointer 
   if (_isrRx) {
     unsigned char status = *_ucsra;
     unsigned char data = *_udr;
-    _isrRx( data, status );
+    _isrRx( data, status, _rxArg );
   }
 
   // default: save data in ring buffer