diff --git a/libraries/AP_HAL_AVR/HAL_AVR_APM1_Class.cpp b/libraries/AP_HAL_AVR/HAL_AVR_APM1_Class.cpp
index ec0b74a176..c376f46b79 100644
--- a/libraries/AP_HAL_AVR/HAL_AVR_APM1_Class.cpp
+++ b/libraries/AP_HAL_AVR/HAL_AVR_APM1_Class.cpp
@@ -21,7 +21,8 @@ AVRUARTDriverInstance(avrUart0Driver, 0);
 AVRUARTDriverInstance(avrUart1Driver, 1);
 AVRUARTDriverInstance(avrUart3Driver, 3);
 
-static AVRI2CDriver     avrI2CDriver;
+static AVRSemaphore     i2cSemaphore;
+static AVRI2CDriver     avrI2CDriver(&i2cSemaphore);
 static APM1SPIDeviceManager apm1SPIDriver;
 static AVRAnalogIn      avrAnalogIn;
 static AVREEPROMStorage avrEEPROMStorage;
diff --git a/libraries/AP_HAL_AVR/HAL_AVR_APM2_Class.cpp b/libraries/AP_HAL_AVR/HAL_AVR_APM2_Class.cpp
index e739ae33f4..9d43541994 100644
--- a/libraries/AP_HAL_AVR/HAL_AVR_APM2_Class.cpp
+++ b/libraries/AP_HAL_AVR/HAL_AVR_APM2_Class.cpp
@@ -21,7 +21,8 @@ AVRUARTDriverInstance(avrUart0Driver, 0);
 AVRUARTDriverInstance(avrUart1Driver, 1);
 AVRUARTDriverInstance(avrUart2Driver, 2);
 
-static AVRI2CDriver     avrI2CDriver;
+static AVRSemaphore     i2cSemaphore;
+static AVRI2CDriver     avrI2CDriver(&i2cSemaphore);
 static APM2SPIDeviceManager apm2SPIDriver;
 static AVRAnalogIn      avrAnalogIn;
 static AVREEPROMStorage avrEEPROMStorage;
diff --git a/libraries/AP_HAL_AVR/I2CDriver.cpp b/libraries/AP_HAL_AVR/I2CDriver.cpp
index f289074fd1..66cb0b0d05 100644
--- a/libraries/AP_HAL_AVR/I2CDriver.cpp
+++ b/libraries/AP_HAL_AVR/I2CDriver.cpp
@@ -316,5 +316,4 @@ SIGNAL(TWI_vect)
     }
 }
 
-
 #endif
diff --git a/libraries/AP_HAL_AVR/I2CDriver.h b/libraries/AP_HAL_AVR/I2CDriver.h
index 91947c4c05..53b9aeac5a 100644
--- a/libraries/AP_HAL_AVR/I2CDriver.h
+++ b/libraries/AP_HAL_AVR/I2CDriver.h
@@ -9,7 +9,7 @@
 
 class AP_HAL_AVR::AVRI2CDriver : public AP_HAL::I2CDriver {
 public:
-    AVRI2CDriver() {}
+    AVRI2CDriver(AP_HAL::Semaphore *sem) : _sem(sem) {}
 
     void begin();
     void end();
@@ -26,6 +26,8 @@ public:
                           uint8_t len, uint8_t* data);
     uint8_t lockup_count() { return _lockup_count; }
 
+    AP_HAL::Semaphore* get_semaphore() { return _sem; }
+
 private:
     uint8_t _start();
     uint8_t _stop();
@@ -39,6 +41,8 @@ private:
     
     uint8_t _lockup_count;
     uint16_t _timeoutDelay;
+
+    AP_HAL::Semaphore *_sem;
 };
 
 #endif // __AP_HAL_AVR_I2C_DRIVER_H__