Merge branch 'wire-master-repeated-starts' of https://github.com/sandeepmistry/ArduinoCore-samd

Author: cmaglie

cores/arduino/SERCOM.cpp

@@ -483,8 +483,8 @@ bool SERCOM::startTransmissionWIRE(uint8_t address, SercomWireReadWriteFlag flag
   // 7-bits address + 1-bits R/W
   address = (address << 0x1ul) | flag;
 
-  // Wait idle bus mode
-  while ( !isBusIdleWIRE() );
+  // Wait idle or owner bus mode
+  while ( !isBusIdleWIRE() && !isBusOwnerWIRE() );
 
   // Send start and address
   sercom->I2CM.ADDR.bit.ADDR = address;
@@ -578,6 +578,11 @@ bool SERCOM::isBusIdleWIRE( void )
   return sercom->I2CM.STATUS.bit.BUSSTATE == WIRE_IDLE_STATE;
 }
 
+bool SERCOM::isBusOwnerWIRE( void )
+{
+  return sercom->I2CM.STATUS.bit.BUSSTATE == WIRE_OWNER_STATE;
+}
+
 bool SERCOM::isDataReadyWIRE( void )
 {
   return sercom->I2CS.INTFLAG.bit.DRDY;

cores/arduino/SERCOM.h

@@ -198,6 +198,7 @@ class SERCOM
 		bool isMasterWIRE( void ) ;
 		bool isSlaveWIRE( void ) ;
 		bool isBusIdleWIRE( void ) ;
+		bool isBusOwnerWIRE( void ) ;
 		bool isDataReadyWIRE( void ) ;
 		bool isStopDetectedWIRE( void ) ;
 		bool isRestartDetectedWIRE( void ) ;

libraries/Wire/Wire.cpp

@@ -85,7 +85,11 @@ uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity, bool stopBit)
     }
     sercom->prepareNackBitWIRE();                           // Prepare NACK to stop slave transmission
     //sercom->readDataWIRE();                               // Clear data register to send NACK
-    sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);   // Send Stop
+
+    if (stopBit)
+    {
+      sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);   // Send Stop
+    }
   }
 
   return byteRead;
@@ -131,7 +135,11 @@ uint8_t TwoWire::endTransmission(bool stopBit)
       return 3 ;  // Nack or error
     }
   }
-  sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
+  
+  if (stopBit)
+  {
+    sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
+  }   
 
   return 0;
 }