diff --git a/build-API.sh b/build-API.sh
index 3efa949..07c175b 100644
--- a/build-API.sh
+++ b/build-API.sh
@@ -22,6 +22,7 @@ rm include_tmp.h
 
 cat include/functions.h >> gnublin.h
 
+cat drivers/driver.h >> gnublin.h
 cat drivers/gpio.h >> gnublin.h
 cat drivers/i2c.h >> gnublin.h
 cat drivers/spi.h >> gnublin.h
@@ -52,6 +53,7 @@ echo "//********************************************
 
 cat include/functions.cpp >> gnublin.cpp
 
+cat drivers/driver.cpp >> gnublin.cpp
 cat drivers/gpio.cpp >> gnublin.cpp
 cat drivers/i2c.cpp >> gnublin.cpp
 cat drivers/spi.cpp >> gnublin.cpp
diff --git a/drivers/adc.cpp b/drivers/adc.cpp
index 0e43ec2..a0252c6 100644
--- a/drivers/adc.cpp
+++ b/drivers/adc.cpp
@@ -18,45 +18,9 @@ gnublin_adc::gnublin_adc(){
 		sleep(1);
 	}
 	file.close();
-	error_flag = false;
+	clearError();
 }
 
-//-------------fail-------------
-/** @~english 
-* @brief Returns the error flag. 
-*
-* If something went wrong, the flag is true.
-* @return bool error_flag
-*
-* @~german 
-* @brief Gibt das Error Flag zurück.
-*
-* Falls das Error Flag in der Klasse gesetzt wurde, wird true zurück gegeben, anderenfalls false.
-* @return bool error_flag
-*/
-bool gnublin_adc::fail(){
-	return error_flag;
-}
-
-
-//-------------getErrorMessage-------------
-/** @~english 
-* @brief Get the last Error Message.
-*
-* This Funktion returns the last Error Message, which occurred in that Class.
-* @return ErrorMessage as c-string
-*
-* @~german 
-* @brief Gibt die letzte Error Nachricht zurück.
-*
-* Diese Funktion gibt die Letzte Error Nachricht zurück, welche in dieser Klasse gespeichert wurde.
-* @return ErrorMessage als c-string
-*/
-const char *gnublin_adc::getErrorMessage(){
-	return ErrorMessage.c_str();
-}
-
-
 //-------------getValue-------------
 /** @~english 
 * @brief Get Value.
@@ -78,16 +42,14 @@ int gnublin_adc::getValue(int pin){
 	std::string pin_str = numberToString(pin);
 	std::string device = "/dev/lpc313x_adc";
 	std::ofstream file(device.c_str());
-	if (file < 0) {
-		error_flag = true;
-		return -1;
-	}
+	if (file < 0) 
+		return setErrorMessage("Unable to open "+device);
 	file << pin_str;
 	file.close();
 	std::ifstream dev_file(device.c_str());
 	dev_file >> value;
 	dev_file.close();
-	error_flag = false;
+	clearError();
 	return hexstringToNumber(value);
 }
 
@@ -126,7 +88,7 @@ int gnublin_adc::getVoltage(int pin){
 * @return Erfolg: 1, Fehler: -1
 */
 int gnublin_adc::setReference(int ref){
-	error_flag = false;
+	clearError();
 	return 1;
 }
 
diff --git a/drivers/adc.h b/drivers/adc.h
index f744c37..1cc8663 100644
--- a/drivers/adc.h
+++ b/drivers/adc.h
@@ -15,17 +15,14 @@
 *
 * Mit der gnublin_adc API lassen sich die GPAs auf dem GNUBLIN einfach aus dem eigenem Programm heraus auslesen.  
 */
-class gnublin_adc {
+class gnublin_adc : public gnublin_driver {
 	public:
 		gnublin_adc();
 		int getValue(int pin);
 		int getVoltage(int pin);
 		int setReference(int ref);
-		bool fail();
-		const char *getErrorMessage();
 	private:
-		bool error_flag;
-		std::string ErrorMessage;
+		void onError() {};
 };
 
 #endif
diff --git a/drivers/driver.cpp b/drivers/driver.cpp
new file mode 100644
index 0000000..93e5988
--- /dev/null
+++ b/drivers/driver.cpp
@@ -0,0 +1,87 @@
+#include "driver.h"
+
+//*******************************************************************
+//Class for accessing GNUBLIN i2c Bus
+//*******************************************************************
+
+//------------------Konstruktor------------------
+/** @~english
+* @brief Sets the error_flag to "false" and the devicefile to "/dev/i2c-1"
+*
+* @~german
+* @brief Setzt das error_flag auf "false" und das devicefile auf standardmäßig "/dev/i2c-1"
+*
+*/
+gnublin_driver::gnublin_driver() 
+{
+	error_flag=false;
+        ErrorMessage="";
+}
+
+//------------------error messaging------------------
+/** @~english
+* @brief Called by the constructors to initialize class variables.
+*
+* @param message String contents that describe the error.
+* @return failure: -1
+*
+* @~german
+* @brief Wird von den Konstruktoren der Klasse Variablen zu initialisieren.
+*
+* @param message String Inhalte, die den Fehler beschreiben.
+* @return failure: -1
+*
+*/
+int gnublin_driver::setErrorMessage(std::string message)
+{
+   ErrorMessage=message;
+   error_flag=true; 
+   return -1; 
+}
+
+//------------------error messaging------------------
+/** @~english
+* @brief Resets the error_flag and other associated details.
+*
+* @~german
+* @brief Setzt die error_flag und anderen damit verbundenen Informationen.
+*
+*/
+void gnublin_driver::clearError()
+{
+   ErrorMessage="";
+   error_flag=false; 
+}
+
+//-------------------------------Fail-------------------------------
+/** @~english 
+* @brief returns the error flag to check if the last operation went wrong
+*
+* @return error_flag as boolean
+*
+* @~german 
+* @brief Gibt das error_flag zurück um zu überprüfen ob die vorangegangene Operation einen Fehler auweist
+*
+* @return error_flag als bool
+*/
+bool gnublin_driver::fail(){
+	return error_flag;
+}
+
+//-------------get Error Message-------------
+/** @~english
+* @brief Get the last Error Message.
+*
+* This function returns the last Error Message, which occurred in that Class.
+* @return ErrorMessage as c-string
+*
+* @~german
+* @brief Gibt die letzte Error Nachricht zurück.
+*
+* Diese Funktion gibt die Letzte Error Nachricht zurück, welche in dieser Klasse gespeichert wurde.
+* @return ErrorMessage als c-string
+*/
+const char *gnublin_driver::getErrorMessage(){
+	return ErrorMessage.c_str();
+}
+
diff --git a/drivers/driver.h b/drivers/driver.h
new file mode 100644
index 0000000..2d682a1
--- /dev/null
+++ b/drivers/driver.h
@@ -0,0 +1,28 @@
+#include "../include/includes.h"
+//*******************************************************************
+//Class for accessing GNUBLIN i2c Bus
+//*******************************************************************
+/**
+* @class gnublin_i2c
+* @~english
+* @brief Class for accessing GNUBLIN i2c bus
+*
+* The GNUBLIN I2C bus can easily accessed with this class
+* @~german 
+* @brief Klasse für den zugriff auf den GNUBLIN I2C Bus
+*
+* Die GNUBLIN I2C Klasse gewährt einfachen Zugriff auf den I2C Bus
+*/ 
+
+class gnublin_driver {
+	bool error_flag;
+	std::string ErrorMessage;
+	virtual void onError() = 0;
+protected:
+	gnublin_driver();
+public:
+	bool fail();
+	int setErrorMessage(std::string message);
+	const char *getErrorMessage();
+        void clearError();
+};
diff --git a/drivers/gpio.cpp b/drivers/gpio.cpp
index b639134..36619c8 100644
--- a/drivers/gpio.cpp
+++ b/drivers/gpio.cpp
@@ -1,4 +1,5 @@
 #include "gpio.h"
+#include "driver.h"
 
 /** @~english 
 * @brief Reset the ErrorFlag.
@@ -7,8 +8,7 @@
 * @brief Setzt das ErrorFlag zurück.
 *
 */
-gnublin_gpio::gnublin_gpio(){
-	error_flag = false;
+gnublin_gpio::gnublin_gpio() : gnublin_driver() {
 }
 
 
@@ -29,49 +29,15 @@ int gnublin_gpio::unexport(int pin){
 	std::string pin_str = numberToString(pin);
 	std::string dir = "/sys/class/gpio/unexport";
 	std::ofstream file (dir.c_str());
-	if (file < 0) {
-		error_flag = true;
-		return -1;
-	}
+	if (file < 0) 
+		return setErrorMessage("Unable to open " + dir +"\n");
 	file << pin_str;
 	file.close();
-	error_flag = false;
+	clearError();
 	return 1;
 }
 
 
-/** @~english 
-* @brief Returns the error flag. 
-*
-* If something went wrong, the flag is true.
-* @return bool error_flag
-*
-* @~german 
-* @brief Gibt das Error Flag zurück.
-*
-* Falls das Error Flag in der Klasse gesetzt wurde, wird true zurück gegeben, anderenfalls false.
-* @return bool error_flag
-*/
-bool gnublin_gpio::fail(){
-	return error_flag;
-}
-
-/** @~english 
-* @brief Get the last Error Message.
-*
-* This Funktion returns the last Error Message, which occurred in that Class.
-* @return ErrorMessage as c-string
-*
-* @~german 
-* @brief Gibt die letzte Error Nachricht zurück.
-*
-* Diese Funktion gibt die Letzte Error Nachricht zurück, welche in dieser Klasse gespeichert wurde.
-* @return ErrorMessage als c-string
-*/
-const char *gnublin_gpio::getErrorMessage(){
-	return ErrorMessage.c_str();
-}
-
 /** @~english 
 * @brief Change the PinMode.
 *
@@ -94,31 +60,26 @@ const char *gnublin_gpio::getErrorMessage(){
 */
 int gnublin_gpio::pinMode(int pin, std::string direction){
 	#if (BOARD != RASPBERRY_PI)
-	if (pin == 4 && direction == "out"){
-		error_flag = true;
-		return -1;
-	}
+	if (pin == 4 && direction == "out")
+                return setErrorMessage("Pin 4 can not be set to 'out'\n");
 	#endif
 	std::string pin_str = numberToString(pin);
 	std::string dir = "/sys/class/gpio/export";
 	std::ofstream file (dir.c_str());
-	if (file < 0) {
-		error_flag = true;
-		return -1;
-	}
+	if (file < 0) 
+                return setErrorMessage("Unable to open " + dir + "\n");
 	file << pin;
 	file.close();
 
 	dir = "/sys/class/gpio/gpio" + pin_str + "/direction";
 
 	file.open(dir.c_str());
-	if (file < 0) {
-		error_flag = true;
-		return -1;
-	}
+	if (file < 0) 
+                return setErrorMessage("Unable to open " + dir + "\n");
 	file << direction;
 	file.close();
-	error_flag = false;
+
+	clearError();
 	return 1;
 }
 
@@ -141,27 +102,21 @@ int gnublin_gpio::pinMode(int pin, std::string direction){
 */
 int gnublin_gpio::digitalWrite(int pin, int value){
 	#if (BOARD != RASPBERRY_PI)
-	if (pin == 4){
-		error_flag = true;
-		return -1;
-	}
+	if (pin == 4)
+                return setErrorMessage("Pin 4 is not available for usage\n");
 	#endif
-	if (value != 0 && value != 1){
-		error_flag = true;
-		return -1;
-	}
+	if (value != 0 && value != 1)
+                return setErrorMessage("Value ["+numberToString(value)+"] must be 0 or 1\n");
 	std::string value_str = numberToString(value);
 	std::string pin_str = numberToString(pin);
 	std::string dir = "/sys/class/gpio/gpio" + pin_str + "/value";
 
 	std::ofstream file (dir.c_str());
-	if (file < 0) {
-		error_flag = true;
-		return -1;
-	}
+	if (file < 0) 
+                return setErrorMessage("Unable to open " + dir + "\n");
 	file << value_str;
 	file.close();
-	error_flag = false;
+	clearError();
 	return 1;
 }
 
@@ -185,13 +140,11 @@ int gnublin_gpio::digitalRead(int pin) {
 	std::string pin_str = numberToString(pin);
 	std::string device = "/sys/class/gpio/gpio" + pin_str + "/value";
 	std::ifstream file(device.c_str());
-	if (file < 0){
-		error_flag = true;
-		return -1;
-	}
+	if (file < 0)
+                return setErrorMessage("Unable to open " + device + "\n");
 	file >> value;
 	file.close();
-	error_flag = false;
+	clearError();
 	return stringToNumber(value);
 	
 }
diff --git a/drivers/gpio.h b/drivers/gpio.h
index 4fbbbe0..0fb7a9e 100644
--- a/drivers/gpio.h
+++ b/drivers/gpio.h
@@ -1,5 +1,4 @@
 #include "../include/includes.h"
-
 /**
 * @class gnublin_gpio
 * @~english
@@ -11,16 +10,12 @@
 *
 * Mit der gnublin_gpio API lassen sich die GPIO-Ports auf dem GNUBLIN einfach aus dem eigenem Programm heraus ansteuern.  
 */
-class gnublin_gpio {
+class gnublin_gpio : public gnublin_driver {
 	public:
 		gnublin_gpio();
-		bool fail();
 		int pinMode(int pin, std::string direction); //Defines GPIO<pin> as INPUT or OUTPUT
 		int digitalWrite(int pin, int value); //Writes value on GPIO
 		int digitalRead(int pin); //Reads value from GPIO<pin>
 		int unexport(int pin);
-		const char *getErrorMessage();
-	private:
-		bool error_flag;
-		std::string ErrorMessage;
+		void onError() {};
 };
diff --git a/drivers/i2c.cpp b/drivers/i2c.cpp
index 867e105..dc7a698 100644
--- a/drivers/i2c.cpp
+++ b/drivers/i2c.cpp
@@ -4,33 +4,149 @@
 //Class for accessing GNUBLIN i2c Bus
 //*******************************************************************
 
-//------------------Konstruktor------------------
+//------------------local defines-----------------
 /** @~english 
-* @brief Sets the error_flag to "false" and the devicefile to "/dev/i2c-1"
+* @brief creates macro reference for default device "/dev/i2c-1"
 *
 * @~german 
-* @brief Setzt das error_flag auf "false" und das devicefile auf standardmäßig "/dev/i2c-1"
+* @brief schafft Makro Referenz für Standard-Gerät "/ dev/i2c-1"
 *
 */
-gnublin_i2c::gnublin_i2c()
+#define DEFAULTDEVICE "/dev/i2c-1"
+
+//------------------Konstruktor------------------
+/** @~english
+* @brief Sets the devicefile to "/dev/i2c-1"
+*
+* @~german
+* @brief Setzt das devicefile auf standardmäßig "/dev/i2c-1"
+*
+*/
+gnublin_i2c::gnublin_i2c() : gnublin_driver()
 {
-	devicefile="/dev/i2c-1";
-	error_flag=false;
+	init(DEFAULTDEVICE, -1);
 }
 
-//-------------------------------Fail-------------------------------
-/** @~english 
-* @brief returns the error flag to check if the last operation went wrong
+//------------------Konstruktor------------------
+/** @~english
+* @brief Sets the devicefile to "/dev/i2c-1"
 *
-* @return error_flag as boolean
+* @~german
+* @brief Setzt das devicefile auf standardmäßig "/dev/i2c-1"
 *
-* @~german 
-* @brief Gibt das error_flag zurück um zu überprüfen ob die vorangegangene Operation einen Fehler auweist
+*/
+gnublin_i2c::gnublin_i2c(int Address) : gnublin_driver()
+{
+	init(DEFAULTDEVICE, Address);
+}
+
+//------------------Konstruktor------------------
+/** @~english
+* @brief Sets the devicefile to "/dev/i2c-1"
+*
+* @~german
+* @brief Setzt das devicefile auf standardmäßig "/dev/i2c-1"
+*
+*/
+gnublin_i2c::gnublin_i2c(std::string Devicefile, int Address) : gnublin_driver()
+{
+	init(Devicefile, Address);
+} 
+
+//------------------destructor------------------
+/** @~english
+* @brief Closes the file handle 
+*
+* @~german
+* @brief Schließt die Datei Griff
 *
-* @return error_flag als bool
 */
-bool gnublin_i2c::fail(){
-	return error_flag;
+gnublin_i2c::~gnublin_i2c()
+{
+	close_fd();
+}
+
+//------------------init------------------
+/** @~english
+* @brief Called by the constructors to initialize class variables.
+*
+* @~german
+* @brief Wird von den Konstruktoren der Klasse Variablen zu initialisieren.
+*
+*/
+void gnublin_i2c::init(std::string Devicefile, int Address) 
+{
+	devicefile=Devicefile;
+        slave_address = Address;
+        fd = 0;
+}
+
+//------------------Error message------------------
+/** @~english
+* @brief Closes the file if open and resets the variable.
+* called from base class when error message is set
+*
+* @~german
+* @brief Schließt die Datei, wenn offen und setzt die Variable.
+* Wird aufgerufen, wenn Fehlermeldung Basisklasse eingestellt ist.
+*
+*/
+void gnublin_i2c::onError()
+{
+   close_fd();
+}
+
+//------------------close file descriptor------------------
+/** @~english
+* @brief Closes the file if open and resets the variable.
+*
+* @~german
+* @brief Schließt die Datei, wenn offen und setzt die Variable.
+*
+*/
+void gnublin_i2c::close_fd()
+{
+    if (fd) {
+        close(fd);
+        fd = 0;
+    }
+}
+
+//------------------open file descriptor------------------
+/** @~english
+* @brief if a file is already open it is closed first.  A new file is opened
+* and io operations defined based on the class values for devicefile 
+* and slave_address.
+*
+* @return failure: -1
+*
+* @~german
+* @brief wenn eine Datei bereits geöffnet ist, wird es zunächst geschlossen. 
+* Eine neue Datei wird geöffnet und IO-Operationen werden auf Basis der Klasse
+* Werte für Device-Datei und Slave_Address definiert.
+*
+* @return failure: -1
+*
+*/
+int gnublin_i2c::open_fd() 
+{
+    clearError();
+
+    if (fd) { 
+        close_fd(); 
+        fd = 0;
+    }
+
+    if (slave_address == -1) 
+        return setErrorMessage("ERROR slave address is not set\n");
+
+    if ((fd = open(devicefile.c_str(), O_RDWR)) < 0) 
+        return setErrorMessage("ERROR opening: " + devicefile + "\n");
+
+    if (ioctl(fd, I2C_SLAVE, slave_address) < 0) 
+        return setErrorMessage("ERROR address: " + numberToString(slave_address) + "\n");
+
+    return 0;
 }
 
 //-------------set Address-------------
@@ -39,15 +155,18 @@ bool gnublin_i2c::fail(){
 *
 * With this function you can set the individual I2C Slave-Address.
 * @param Address new I2C slave Address
+* @return failure: -1 
 *
 * @~german 
 * @brief Setzt die i2c slave Adresse
 *
 * Mit dieser Funktion kann die individuelle I2C Slave-Adresse gesetzt werden.
 * @param Address neue I2C slave Adresse
+* @return failure: -1 
 */
-void gnublin_i2c::setAddress(int Address){
+int gnublin_i2c::setAddress(int Address){
 	slave_address = Address;
+	return open_fd();
 }
 
 //-------------get Address-------------
@@ -67,38 +186,24 @@ int gnublin_i2c::getAddress(){
 	return slave_address;
 }
 
-//-------------get Error Message-------------
-/** @~english 
-* @brief Get the last Error Message.
-*
-* This function returns the last Error Message, which occurred in that Class.
-* @return ErrorMessage as c-string
-*
-* @~german 
-* @brief Gibt die letzte Error Nachricht zurück.
-*
-* Diese Funktion gibt die Letzte Error Nachricht zurück, welche in dieser Klasse gespeichert wurde.
-* @return ErrorMessage als c-string
-*/
-const char *gnublin_i2c::getErrorMessage(){
-	return ErrorMessage.c_str();
-}
-
 //-------------------set devicefile----------------
 /** @~english
 * @brief set i2c the device file. default is "/dev/i2c-1"
 *
 * This function sets the devicefile you want to access. by default "/dev/i2c-1" is set.
 * @param filename path to the devicefile e.g. "/dev/i2c-0"
+* @return failure: -1 
 *
 * @~german
 * @brief setzt die I2C Device Datei. Standard ist die "/dev/i2c-1"
 *
 * Diese Funktion setzt die Geräte Datei, auf die man zugreifen möchte. Standardmäßig ist bereits "/dev/i2c-1" gesetzt.
 * @param filename Dateipfad zur Geräte Datei, z.B. "/dev/i2c-0"
+* @return failure: -1 
 */
-void gnublin_i2c::setDevicefile(std::string filename){
+int gnublin_i2c::setDevicefile(std::string filename){
 	devicefile = filename;
+	return open_fd();
 }
 
 
@@ -126,32 +231,21 @@ void gnublin_i2c::setDevicefile(std::string filename){
 * @return Erfolg: 1, Misserfolg: -1
 */
 int gnublin_i2c::receive(unsigned char *RxBuf, int length){
-	error_flag=false;
-	int fd;
 
+	if (RxBuf == 0)
+		return setErrorMessage("Receive method received a null TxBuf pointer.\n");
+	if (length < 1)
+		return setErrorMessage("Receive method received an invalid buffer length.\n");
 
-	if ((fd = open(devicefile.c_str(), O_RDWR)) < 0) {
-		ErrorMessage="ERROR opening: " + devicefile + "\n";
-		error_flag=true;
-		close(fd);    	
-		return -1;
-	}
-
-	if (ioctl(fd, I2C_SLAVE, slave_address) < 0) {
-		ErrorMessage="ERROR address: " + numberToString(slave_address) + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-  	}
-
-	if (read(fd, RxBuf, length) != length){
-		ErrorMessage="i2c read error! Address: " + numberToString(slave_address) + " dev file: " + devicefile + "\n";		
-		error_flag=true; 
-		close(fd);
-		return -1;
-	}
+	if (!fd)
+		if (open_fd() == -1)
+			return -1;
+
+	clearError();	
+
+	if (read(fd, RxBuf, length) != length)
+		return setErrorMessage("i2c read error! Address: " + numberToString(slave_address) + " dev file: " + devicefile + "\n");		
 
-	close(fd); 
 	return 1;
 }
 
@@ -187,39 +281,24 @@ int gnublin_i2c::receive(unsigned char *RxBuf, int length){
 * @return Erfolg: 1, Misserfolg: -1
 */
 int gnublin_i2c::receive(unsigned char RegisterAddress, unsigned char *RxBuf, int length){
-	error_flag=false;	
-	int fd;
-
-	if ((fd = open(devicefile.c_str(), O_RDWR)) < 0) {
-		ErrorMessage="ERROR opening: " + devicefile + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-	}
-
-	if (ioctl(fd, I2C_SLAVE, slave_address) < 0) {
-		ErrorMessage="ERROR address: " + numberToString(slave_address) + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-  	}
-
-	if (write(fd, &RegisterAddress, 1) != 1){
-		ErrorMessage="i2c write error!\n";
-		error_flag=true; 
-		close(fd);
-		return -1;
-		}
 
+	if (RxBuf == 0)
+		return setErrorMessage("Receive method received a null TxBuf pointer.\n");
+	if (length < 1)
+		return setErrorMessage("Receive method received an invalid buffer length.\n");
 
-	if (read(fd, RxBuf, length) != length){
-		ErrorMessage="i2c read error! Address: " + numberToString(slave_address) + " dev file: " + devicefile + "\n";
-		error_flag=true; 
-		close(fd);
-		return -1;
-	}
+	if (!fd)
+		if (open_fd() == -1)
+			return -1;
+
+	clearError();
+
+	if (write(fd, &RegisterAddress, 1) != 1)
+  		return setErrorMessage("i2c write error!\n");
+
+	if (read(fd, RxBuf, length) != length)
+		return setErrorMessage("i2c read error! Address: " + numberToString(slave_address) + " dev file: " + devicefile + "\n");
 
-	close(fd); 	 
 	return 1;
 }
 
@@ -247,31 +326,21 @@ int gnublin_i2c::receive(unsigned char RegisterAddress, unsigned char *RxBuf, in
 * @return Erfolg: 1, Misserfolg: -1
 */
 int gnublin_i2c::send(unsigned char *TxBuf, int length){
-	error_flag=false;	
-	int fd; 
-
-	if ((fd = open(devicefile.c_str(), O_RDWR)) < 0) {
-		ErrorMessage="ERROR opening: " + devicefile + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-	}
-
-	if (ioctl(fd, I2C_SLAVE, slave_address) < 0) {
-		ErrorMessage="ERROR address: " + numberToString(slave_address) + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-  	}
-
-	if(write(fd, TxBuf, length) != length){
-		ErrorMessage="i2c write error!\n";
-		error_flag=true; 
-		close(fd);
-		return -1;
-	}
 
-	close(fd);	
+	if (TxBuf == 0)
+		return setErrorMessage("Send method received a null TxBuf pointer.\n");
+	if (length < 1)
+		return setErrorMessage("Send method received an invalid buffer length.\n");
+
+	if (!fd)
+		if (open_fd() == -1)
+			  return -1;
+
+        clearError();
+
+	if(write(fd, TxBuf, length) != length)
+		return setErrorMessage("i2c write error!\n");
+
 	return 1;
 }
 
@@ -307,38 +376,24 @@ int gnublin_i2c::send(unsigned char *TxBuf, int length){
 * @return Erfolg: 1, Misserfolg: -1
 */
 int gnublin_i2c::send(unsigned char RegisterAddress, unsigned char *TxBuf, int length){
-	error_flag=false;	
-	int fd, i;
-	unsigned char data[length+1];
-	data[0]=RegisterAddress;
-
-	for ( i = 0; i < length ; i++ ) {
-		data[ i + 1 ] = (char)TxBuf[ i ];
-	}
-
-	if ((fd = open(devicefile.c_str(), O_RDWR)) < 0) {
-		ErrorMessage="ERROR opening: " + devicefile + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-	}
-
-	if (ioctl(fd, I2C_SLAVE, slave_address) < 0) {
-		ErrorMessage="ERROR address: " + numberToString(slave_address) + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-  	}
-	
-	
-	if(write(fd, data, length+1) != length+1){
-		ErrorMessage="i2c write error!\n";
-		error_flag=true; 
-		close(fd);
+
+	if (TxBuf == 0)
+		return setErrorMessage("Send method received a null TxBuf pointer.\n");
+	if (length < 1)
+		return setErrorMessage("Send method received an invalid buffer length.\n");
+
+	if (!fd)
+		if (open_fd() == -1)
+			return -1;
+
+	clearError();
+
+	if (send(RegisterAddress) == -1)
 		return -1;
-	}
 
-	close(fd);	
+	if(write(fd, TxBuf, length) != length)
+		return setErrorMessage("i2c write error!\n");
+
 	return 1;
 }
 
@@ -363,33 +418,16 @@ int gnublin_i2c::send(unsigned char RegisterAddress, unsigned char *TxBuf, int l
 * @param value Byte das gesendet wird.
 * @return Erfolg: 1, Misserfolg: -1
 */
-int gnublin_i2c::send(int value){
-	error_flag=false;
-	int buffer[1];
-	buffer[0]=value;	
-	int fd; 
-
-	if ((fd = open(devicefile.c_str(), O_RDWR)) < 0) {
-		ErrorMessage="ERROR opening: " + devicefile + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-	}
-
-	if (ioctl(fd, I2C_SLAVE, slave_address) < 0) {
-		ErrorMessage="ERROR address: " + numberToString(slave_address) + "\n";
-		error_flag=true; 
-		close(fd);
-    	return -1;
-  	}
-
-	if(write(fd, buffer, 1) != 1){
-		ErrorMessage="i2c write error!\n";
-		error_flag=true; 
-		close(fd);
-		return -1;
-	}
+int gnublin_i2c::send(unsigned char value){
+
+	if (!fd)
+		if (open_fd() == -1)
+			  return -1;
+
+	clearError();
+
+	if(write(fd, &value, 1) != 1)
+		return setErrorMessage("i2c write error!\n");
 
-	close(fd);	
 	return 1;
 }
diff --git a/drivers/i2c.h b/drivers/i2c.h
index 107a73b..eb2abfe 100644
--- a/drivers/i2c.h
+++ b/drivers/i2c.h
@@ -1,4 +1,5 @@
 #include "../include/includes.h"
+#include "driver.h"
 //*******************************************************************
 //Class for accessing GNUBLIN i2c Bus
 //*******************************************************************
@@ -14,21 +15,25 @@
 * Die GNUBLIN I2C Klasse gewährt einfachen Zugriff auf den I2C Bus
 */ 
 
-class gnublin_i2c {
-	bool error_flag;
+class gnublin_i2c : public gnublin_driver {
 	int slave_address;
 	std::string devicefile;
-	std::string ErrorMessage;
+	int fd;
+	int open_fd();
+	void close_fd();
+	void init(std::string DeviceFile, int Address);
+        void onError();
 public:
 	gnublin_i2c();
-	bool fail();
-	void setAddress(int Address);
+	gnublin_i2c(int Address);
+	gnublin_i2c(std::string DeviceFile, int Address);
+	~gnublin_i2c();
+	int setAddress(int Address);
 	int getAddress();
-	const char *getErrorMessage();
-	void setDevicefile(std::string filename);
+	int setDevicefile(std::string filename);
 	int receive(unsigned char *RxBuf, int length);
 	int receive(unsigned char RegisterAddress, unsigned char *RxBuf, int length);
 	int send(unsigned char *TxBuf, int length);
 	int send(unsigned char RegisterAddress, unsigned char *TxBuf, int length);
-	int send(int value);
+	int send(unsigned char value);
 };
diff --git a/drivers/spi.cpp b/drivers/spi.cpp
index a608709..8f61d12 100644
--- a/drivers/spi.cpp
+++ b/drivers/spi.cpp
@@ -1,6 +1,5 @@
 #include "spi.h"
 
-
 //***************************************************************************
 // Class for accessing the SPI-Bus
 //***************************************************************************
@@ -19,8 +18,8 @@
 * GNUBLIN: CS = 11
 * RASPBERRY PI: CS = 0
 */
-gnublin_spi::gnublin_spi(){
-	error_flag = false;
+gnublin_spi::gnublin_spi() : gnublin_driver()
+{
 	#if BOARD == RASPBERRY_PI
 	std::string device = "/dev/spidev0.0";
 	#else
@@ -35,6 +34,8 @@ gnublin_spi::gnublin_spi(){
 		#endif
 		sleep(1);
 		fd = open(device.c_str(), O_RDWR);
+		if (fd < 0)
+			setErrorMessage("Unable to open file "+device+"\n");
 	}
 }
 
@@ -45,41 +46,6 @@ gnublin_spi::~gnublin_spi(){
 	close(fd);
 }
 
-
-//******************** fail() ***********************************************
-/**
-* @~english
-* @brief Returns the errorflag to detect error in the previous called method.
-*
-* @return error_flag
-*
-* @~german
-* @brief Gibt das errorflag zurück, um Fehler in der zuvor aufgerugfenen Methode zu erkennen.
-*
-* @return error_flag
-*/
-bool gnublin_spi::fail(){
-	return error_flag;
-}
-
-
-//-------------get Error Message-------------
-/**
-* @~english
-* @brief Returns the ErrorMessage of the previous error if one exist.
-*
-* @return ErrorMessage as C-String
-*
-* @~german
-* @brief Gibt die Fehlernachricht des zuvor aufgetretenen Fehlers zurück, wenn weine exisitert.
-*
-* @return ErrorMessage als C-String
-*/
-const char *gnublin_spi::getErrorMessage(){
-	return ErrorMessage.c_str();
-}
-
-
 //*********************** setCS *********************************************
 
 /**
@@ -108,12 +74,10 @@ int gnublin_spi::setCS(int cs){
 		system(command.c_str());
 		sleep(1);
 		fd = open(device.c_str(), O_RDWR);
-		if (fd < 0){
-			error_flag = true;
-			return -1;
-		}
+		if (fd < 0)
+		    return setErrorMessage("Unable to open file "+device+"\n");
 	}
-	error_flag = false;
+        clearError();
 	return 1;
 }
 
@@ -134,11 +98,9 @@ int gnublin_spi::setCS(int cs){
 * @return 1 bei Erfolg, -1 im Fehlerfall
 */
 int gnublin_spi::setMode(unsigned char mode){
-	if (ioctl(fd, SPI_IOC_WR_MODE, &mode) < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (ioctl(fd, SPI_IOC_WR_MODE, &mode) < 0)
+		return setErrorMessage("ioctl failed.");
+        clearError();
 	return 1;
 }
 
@@ -158,11 +120,9 @@ int gnublin_spi::setMode(unsigned char mode){
 */
 int gnublin_spi::getMode(){
 	__u8 mode;
-	if (ioctl(fd, SPI_IOC_RD_MODE, &mode) < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (ioctl(fd, SPI_IOC_RD_MODE, &mode) < 0)
+		return setErrorMessage("ioctl failed.");
+	clearError();
 	return mode;
 }
 
@@ -183,11 +143,9 @@ int gnublin_spi::getMode(){
 * @return 1 bei Erfolg, -1 im Fehlerfall
 */
 int gnublin_spi::setLSB(unsigned char lsb){
-	if (ioctl(fd, SPI_IOC_WR_LSB_FIRST, &lsb) < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (ioctl(fd, SPI_IOC_WR_LSB_FIRST, &lsb) < 0)
+		return setErrorMessage("ioctl failed.");
+	clearError();
 	return 1;
 }
 
@@ -207,11 +165,9 @@ int gnublin_spi::setLSB(unsigned char lsb){
 */
 int gnublin_spi::getLSB(){
 	__u8 lsb;
-	if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) {
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) 
+		return setErrorMessage("ioctl failed.");
+	clearError();
 	return lsb;
 }
 
@@ -232,11 +188,9 @@ int gnublin_spi::getLSB(){
 * @return 1 bei Erfolg, -1 im Fehlerfall
 */
 int gnublin_spi::setLength(unsigned char bits){
-	if (ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits) < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits) < 0)
+		return setErrorMessage("ioctl failed.");
+	clearError();
 	return 1;
 }
 
@@ -256,11 +210,9 @@ int gnublin_spi::setLength(unsigned char bits){
 */
 int gnublin_spi::getLength(){
 	__u8 bits;
-	if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0)
+		return setErrorMessage("ioctl failed.");
+	clearError();
 	return bits;
 }
 
@@ -281,11 +233,9 @@ int gnublin_spi::getLength(){
 * @return 1 bei Erfolg, -1 im Fehlerfall
 */
 int gnublin_spi::setSpeed(unsigned int speed){
-	if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = true;
+	if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) < 0)
+		return setErrorMessage("ioctl failed.");
+	clearError();
 	return 1;
 }
 
@@ -305,11 +255,9 @@ int gnublin_spi::setSpeed(unsigned int speed){
 */
 int gnublin_spi::getSpeed(){
 	__u32 speed;
-	if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0)
+		return setErrorMessage("ioctl failed.");
+	clearError();
 	return speed;
 }
 
@@ -331,11 +279,9 @@ int gnublin_spi::getSpeed(){
 * @return 1 bei Erfolg, -1 im Fehlerfall
 */
 int gnublin_spi::receive(char* buffer, int len){
-	if (read(fd, buffer, len) < 0) {
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (read(fd, buffer, len) < 0) 
+		return setErrorMessage("read failed.");
+	clearError();
 	return 1;
 }
 
@@ -366,11 +312,9 @@ int gnublin_spi::send(unsigned char* tx, int length){
 	xfer.speed_hz = 0;
 	xfer.bits_per_word = 0;
 	status = ioctl(fd, SPI_IOC_MESSAGE(1), &xfer);
-	if ( status < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if ( status < 0)
+		return setErrorMessage("ioctl status shows failure.");
+	clearError();
 	return 1;
 }
 
@@ -414,11 +358,9 @@ int gnublin_spi::message(unsigned char* tx, int tx_length, unsigned char* rx, in
 	xfer[1].bits_per_word = 0;
 
 	status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer);
-	if (status < 0){
-		error_flag = true;
-		return -1;
-	}
-	error_flag = false;
+	if (status < 0)
+		return setErrorMessage("ioctl status shows failure.");
+	clearError();
 	return 1;
 }
 
diff --git a/drivers/spi.h b/drivers/spi.h
index 81d521e..3e80fff 100644
--- a/drivers/spi.h
+++ b/drivers/spi.h
@@ -1,5 +1,5 @@
 #include "../include/includes.h"
-
+#include "driver.h"
 //***************************************************************************
 // Class for accessing the SPI-Bus
 //***************************************************************************
@@ -15,7 +15,7 @@
 *
 * Diese Klasse ermöglicht das Senden und Empfangen von Daten über den SPI-Bus.
 */
-class gnublin_spi{
+class gnublin_spi : gnublin_driver {
 	public:
 		gnublin_spi();
 		~gnublin_spi();
@@ -31,11 +31,7 @@ class gnublin_spi{
 		int send(unsigned char* tx, int length);
 		int setCS(int cs);
 		int message(unsigned char* tx, int tx_length, unsigned char* rx, int rx_length);
-		const char *getErrorMessage();
-		bool fail();
 	private:
 		int fd;
-		bool error_flag;
-		std::string ErrorMessage;
-		
+		void onError() {};	
 };