diff --git a/include/sta/bus/i2c/device.hpp b/include/sta/bus/i2c/device.hpp
index 88485b3..5894b5b 100644
--- a/include/sta/bus/i2c/device.hpp
+++ b/include/sta/bus/i2c/device.hpp
@@ -18,11 +18,10 @@ namespace sta
          * @param intf      %I2C hardware interface
          * @param csPin     The peripheral's address.
          */
-        I2CDevice(I2C * intf, int address, bool master=false, bool blocking=true);
+        I2CDevice(I2C * intf, int address, bool master=true, bool blocking=true);
 
     protected:
         void select() override;
-
         void deselect() override;
 
     private:
diff --git a/include/sta/config.hpp b/include/sta/config.hpp
index f798ba8..725478f 100644
--- a/include/sta/config.hpp
+++ b/include/sta/config.hpp
@@ -1,7 +1,8 @@
 #ifndef STA_CONFIG_HPP
 #define STA_CONFIG_HPP
 
-#include <sta/devices/stm32/mcu/STM32F411xE.hpp>
+// #include <sta/devices/stm32/mcu/STM32F411xE.hpp>
+#include <sta/devices/raspi/mcu/common.hpp>
 
 #define STA_DEBUGGING_ENABLED
 #define STA_PRINTF_USE_STDLIB
diff --git a/include/sta/devices/raspi/bus/i2c.hpp b/include/sta/devices/raspi/bus/i2c.hpp
index c4c8ee7..5e9d6a5 100644
--- a/include/sta/devices/raspi/bus/i2c.hpp
+++ b/include/sta/devices/raspi/bus/i2c.hpp
@@ -28,6 +28,7 @@ namespace sta
         void transfer(const uint8_t * buffer, size_t size) override;
         void receive(uint8_t * buffer, size_t size) override;
 
+        void selectAddress();
         void acquire() override;
         void release() override;
 
@@ -41,7 +42,8 @@ namespace sta
 
     class RaspiI2CDevice : public I2CDevice
     {
-        RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, Mutex* mutex=nullptr, bool master=false, bool blocking=true);
+    public:
+        RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, bool master=true, bool blocking=true);
     };
 } // namespace sta
 
diff --git a/src/bus/interface.cpp b/src/bus/interface.cpp
index b7ff0a7..8560b3b 100644
--- a/src/bus/interface.cpp
+++ b/src/bus/interface.cpp
@@ -12,16 +12,14 @@ namespace sta
 
     void Interface::acquire()
     {
-        if (mutex_ != nullptr)
-            mutex_->acquire();
-        	acquired_ = true;
+        mutex_->acquire();
+        acquired_ = true;
     }
 
     void Interface::release()
     {
-        if (mutex_ != nullptr)
-        	acquired_ = false;
-            mutex_->release();
+        mutex_->release();
+        acquired_ = false;
     }
 
     bool Interface::isAcquired()
diff --git a/src/devices/raspi/bus/i2c.cpp b/src/devices/raspi/bus/i2c.cpp
index bb23bf2..35850a3 100644
--- a/src/devices/raspi/bus/i2c.cpp
+++ b/src/devices/raspi/bus/i2c.cpp
@@ -3,6 +3,7 @@
 #ifdef STA_PLATFORM_RASPI
 
 #include <sta/debug/assert.hpp>
+#include <sta/debug/debug.hpp>
 
 #include <cstdlib>
 #include <string.h>
@@ -11,6 +12,7 @@
 #include <linux/i2c-dev.h>
 #include <sys/ioctl.h>
 #include <fcntl.h>
+#include <errno.h>
 #include <unistd.h>
 
 
@@ -41,46 +43,67 @@ namespace sta
     {
         STA_ASSERT(open_);
 
-        write(i2cfd_, &value, 1);
+        selectAddress();
+        ssize_t n_out = write(i2cfd_, &value, 1);
+
+        STA_ASSERT(n_out == 1);
     }
 
     void RaspiI2C::transfer16(uint16_t value)
     {
         STA_ASSERT(open_);
 
-        write(i2cfd_, &value, 2);
+        selectAddress();
+        ssize_t n_out = write(i2cfd_, &value, 2);
+
+        STA_ASSERT(n_out == 2);
     }
 
     void RaspiI2C::transfer(const uint8_t * buffer, size_t size)
     {
         STA_ASSERT(open_);
 
-        write(i2cfd_, buffer, size);
+        selectAddress();
+        ssize_t n_out = write(i2cfd_, buffer, size);
+
+        STA_ASSERT(n_out == size);
     }
 
     void RaspiI2C::receive(uint8_t * buffer, size_t size)
     {
         STA_ASSERT(open_);
 
-        if (read(i2cfd_, buffer, size) <= 0)
-        {
-            printf("Error while reading i2c bus.");
-        }
+        selectAddress();
+        ssize_t n_in = read(i2cfd_, buffer, size);
+
+        STA_ASSERT(n_in >= 0);
     }
 
     void RaspiI2C::fill(uint8_t value, size_t count) 
     {
         STA_ASSERT(open_);
 
+        selectAddress();
+
         // Initialize a buffer of size count and fill it with the value.
         uint8_t *buffer = new uint8_t[count];
         memset(buffer, value, count);
 
-        write(i2cfd_, buffer, count);
+        ssize_t n_out = write(i2cfd_, buffer, count);
+
+        STA_ASSERT(n_out == count);
 
         delete [] buffer; 
     }
 
+    void RaspiI2C::selectAddress()
+    {
+        // Select the slave with the given address.
+        int rslt = ioctl(i2cfd_, I2C_SLAVE, address_);
+
+        STA_ASSERT(rslt != -1);
+    }
+
     void RaspiI2C::acquire()
     {
         I2C::acquire();
@@ -99,16 +122,19 @@ namespace sta
     {
         if (!persistent_open_ && open_) {
             close(i2cfd_);
+            open_ = false;
         }
 
         I2C::release();
     }
 
-    RaspiI2CDevice::RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, Mutex* mutex, bool master, bool blocking) 
-        : I2CDevice { intf, address_10bit }
+    RaspiI2CDevice::RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, bool master, bool blocking) 
+        : I2CDevice { intf, address_10bit, master, blocking }
     {
         
     }
+
+
 } // namespace sta
 
 #endif // STA_PLATFORM_RASPI