Add function to check I2C peripheral status

libraries/Wire/src/Wire.cpp

@@ -372,7 +372,11 @@ void TwoWire::onRequest( void (*function)(void) )
   user_onRequest = function;
 }
 
+bool TwoWire::isBusy(void)
+{
+  return twi_isSollicited();
+}
+
 // Preinstantiate Objects //////////////////////////////////////////////////////
 
 TwoWire Wire = TwoWire();
-

libraries/Wire/src/Wire.h

@@ -75,6 +75,7 @@ class TwoWire : public Stream
     virtual void flush(void);
     void onReceive( void (*)(int) );
     void onRequest( void (*)(void) );
+    bool isBusy(void);
 
     inline size_t write(unsigned long n) { return write((uint8_t)n); }
     inline size_t write(long n) { return write((uint8_t)n); }

libraries/Wire/src/utility/twi.c

@@ -500,6 +500,10 @@ bool twi_manageTimeoutFlag(bool clear_flag){
   return(flag);
 }
 
+bool twi_isSollicited(void){
+  return twi_state == TWI_SRX || twi_state == TWI_STX;
+}
+
 ISR(TWI_vect)
 {
   switch(TW_STATUS){

libraries/Wire/src/utility/twi.h

@@ -55,5 +55,6 @@
   void twi_setTimeoutInMicros(uint32_t, bool);
   void twi_handleTimeout(bool);
   bool twi_manageTimeoutFlag(bool);
+  bool twi_isSollicited(void);
 
 #endif