5 files changed, 35 insertions, 6 deletions
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp
index 835b794..2bd48ed 100644
--- a/libraries/Wire/Wire.cpp
+++ b/libraries/Wire/Wire.cpp
@@ -75,6 +75,11 @@ void TwoWire::begin(int address)
   begin((uint8_t)address);
 }
 
+void TwoWire::end(void)
+{
+  twi_disable();
+}
+
 void TwoWire::setClock(uint32_t frequency)
 {
   TWBR = ((F_CPU / frequency) - 16) / 2;
diff --git a/libraries/Wire/Wire.h b/libraries/Wire/Wire.h
index 7d00959..702f37d 100644
--- a/libraries/Wire/Wire.h
+++ b/libraries/Wire/Wire.h
@@ -27,6 +27,9 @@
 
 #define BUFFER_LENGTH 32
 
+// WIRE_HAS_END means Wire has end()
+#define WIRE_HAS_END 1
+
 class TwoWire : public Stream
 {
   private:
@@ -49,6 +52,7 @@ class TwoWire : public Stream
     void begin();
     void begin(uint8_t);
     void begin(int);
+    void end();
     void setClock(uint32_t);
     void beginTransmission(uint8_t);
     void beginTransmission(int);
diff --git a/libraries/Wire/library.properties b/libraries/Wire/library.properties
index 0805847..811527b 100644
--- a/libraries/Wire/library.properties
+++ b/libraries/Wire/library.properties
@@ -4,6 +4,7 @@ author=Arduino
 maintainer=Arduino <info@arduino.cc>
 sentence=Allows the communication between devices or sensors connected via Two Wire Interface Bus. For all Arduino boards, BUT Arduino DUE. 
 paragraph=
+category=Communication
 url=http://www.arduino.cc/en/Reference/Wire
 architectures=avr
 
diff --git a/libraries/Wire/utility/twi.c b/libraries/Wire/utility/twi.c
index 201d7d1..2af0597 100644
--- a/libraries/Wire/utility/twi.c
+++ b/libraries/Wire/utility/twi.c
@@ -91,6 +91,22 @@ void twi_init(void)
 }
 
 /* 
+ * Function twi_disable
+ * Desc     disables twi pins
+ * Input    none
+ * Output   none
+ */
+void twi_disable(void)
+{
+  // disable twi module, acks, and twi interrupt
+  TWCR &= ~(_BV(TWEN) | _BV(TWIE) | _BV(TWEA));
+
+  // deactivate internal pullups for twi.
+  digitalWrite(SDA, 0);
+  digitalWrite(SCL, 0);
+}
+
+/* 
  * Function twi_slaveInit
  * Desc     sets slave address and enables interrupt
  * Input    none
@@ -151,7 +167,9 @@ uint8_t twi_readFrom(uint8_t address, uint8_t* data, uint8_t length, uint8_t sen
     // up. Also, don't enable the START interrupt. There may be one pending from the 
     // repeated start that we sent outselves, and that would really confuse things.
     twi_inRepStart = false;			// remember, we're dealing with an ASYNC ISR
-    TWDR = twi_slarw;
+    do {
+      TWDR = twi_slarw;
+    } while(TWCR & _BV(TWWC));
     TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE);	// enable INTs, but not START
   }
   else
@@ -231,7 +249,9 @@ uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait
     // up. Also, don't enable the START interrupt. There may be one pending from the 
     // repeated start that we sent outselves, and that would really confuse things.
     twi_inRepStart = false;			// remember, we're dealing with an ASYNC ISR
-    TWDR = twi_slarw;				
+    do {
+      TWDR = twi_slarw;				
+    } while(TWCR & _BV(TWWC));
     TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE);	// enable INTs, but not START
   }
   else
@@ -460,18 +480,16 @@ ISR(TWI_vect)
       }
       break;
     case TW_SR_STOP: // stop or repeated start condition received
+      // ack future responses and leave slave receiver state
+      twi_releaseBus();
       // put a null char after data if there's room
       if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){
         twi_rxBuffer[twi_rxBufferIndex] = '\0';
       }
-      // sends ack and stops interface for clock stretching
-      twi_stop();
       // callback to user defined callback
       twi_onSlaveReceive(twi_rxBuffer, twi_rxBufferIndex);
       // since we submit rx buffer to "wire" library, we can reset it
       twi_rxBufferIndex = 0;
-      // ack future responses and leave slave receiver state
-      twi_releaseBus();
       break;
     case TW_SR_DATA_NACK:       // data received, returned nack
     case TW_SR_GCALL_DATA_NACK: // data received generally, returned nack
diff --git a/libraries/Wire/utility/twi.h b/libraries/Wire/utility/twi.h
index 6526593..4c52bc5 100644
--- a/libraries/Wire/utility/twi.h
+++ b/libraries/Wire/utility/twi.h
@@ -39,6 +39,7 @@
   #define TWI_STX   4
   
   void twi_init(void);
+  void twi_disable(void);
   void twi_setAddress(uint8_t);
   uint8_t twi_readFrom(uint8_t, uint8_t*, uint8_t, uint8_t);
   uint8_t twi_writeTo(uint8_t, uint8_t*, uint8_t, uint8_t, uint8_t);