diff --git a/platform/osd-merkur/Makefile.osd-merkur b/platform/osd-merkur/Makefile.osd-merkur
index 31e3afb92..3fb160bdd 100644
--- a/platform/osd-merkur/Makefile.osd-merkur
+++ b/platform/osd-merkur/Makefile.osd-merkur
@@ -7,6 +7,8 @@ CONTIKI_TARGET_SOURCEFILES += contiki-main.c params.c node-id.c
 CONTIKI_TARGET_SOURCEFILES += temperature-sensor.c adc.c led.c sensors.c slip_uart0.c slip.c leds-arch.c
 #Needed for Button
 CONTIKI_TARGET_SOURCEFILES += button-sensor.c
+# i2c Master
+CONTIKI_TARGET_SOURCEFILES += i2c.c
 #Needed for DHT11 humidity sensor
 CONTIKI_TARGET_SOURCEFILES += dht11.c
 #Needed for DS18S20 temperature sensor
diff --git a/platform/osd-merkur/dev/i2c.c b/platform/osd-merkur/dev/i2c.c
new file mode 100644
index 000000000..d5fe8d34a
--- /dev/null
+++ b/platform/osd-merkur/dev/i2c.c
@@ -0,0 +1,391 @@
+/*
+ * Copyright (c) 2014, Ingo Gulyas Intembsys
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ */
+
+ /**
+ * \file
+ *         I2C driver for ATMEGA128rfa1
+ *
+ * \author
+ *         Ingo Gulyas Intembsys
+ *         office@intembsys.at
+ *         www.intembsys.at
+ */
+
+
+#include "i2c.h"
+#include "contiki-conf.h"
+#include <stdint.h>
+#include <avr/power.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#if I2C_TD != 0
+#include <stdio.h>
+#include <avr/pgmspace.h>
+#include "system_mgmt.h"
+#define PRINTD(FORMAT,args...) {sleep_acquire_lock(); printf_P(PSTR(FORMAT),##args); sleep_release_lock();}
+#else
+#define PRINTD(...)
+#endif
+
+#if WITH_RTDEBUG == 1
+#include "rtdebug.h"
+#define RTDEBUG_PUSH(x) rtdebug_push(x)
+#else
+#warning "I2C Driver compiling without RTDEBUG!"
+#define RTDEBUG_PUSH(x)
+#endif
+
+#ifndef TIMEOUT_TIMER
+#warning "I2C Driver compiling without TIMEOUT!"
+#endif
+
+
+static int8_t wait_job();
+static int8_t wait_stop();
+
+static int8_t i2c_ioctl(const i2c_driver* const me, uint8_t cmd, uint8_t arg);
+static int8_t i2c_read(const i2c_driver* const me, uint8_t cmd_flags, uint8_t* buffer, uint8_t len);
+static int8_t i2c_write(const i2c_driver* const me, uint8_t cmd_flags, const uint8_t* data, uint8_t len);
+
+
+// static linkage of member functions
+i2c_driver i2c_drv = {i2c_ioctl, i2c_read, i2c_write};
+// lock spi if driver opened to prevent further opening access
+static volatile bool i2c_lock = false;
+
+
+///////////////////////////////////////////////////////////////
+// global functions
+///////////////////////////////////////////////////////////////
+
+i2c_driver* i2c_open(void)
+{
+	if(i2c_lock == true)
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_OPEN__DEVICE_BUSY);
+		return NULL;
+	}	
+	 
+	i2c_lock = true;
+	power_twi_enable();
+	I2C_INIT();	
+
+	TWBR = I2C_FREQ_STANDARD;
+	TWSR &= ~((1<<TWPS1) | (1<<TWPS0));
+	TWSR |= (1<<TWPS0);
+	TWCR = (1<<TWEN);
+	
+	return &i2c_drv;
+}
+
+void i2c_close(i2c_driver* const me)
+{
+	if(me == NULL || i2c_lock == false)
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_CLOSE__NO_DEVICE);
+		return;
+	}
+	
+	i2c_reset();
+	
+	return;
+}
+
+void i2c_reset(void)
+{
+	TWCR &= ~(1<<TWEN);
+	I2C_DEINIT();
+	power_twi_disable();
+	i2c_lock = false;
+	
+	return;
+}
+
+
+///////////////////////////////////////////////////////////////
+// local helper functions
+///////////////////////////////////////////////////////////////
+
+#ifdef TIMEOUT_TIMER
+	static int8_t wait_job()
+	{
+		int8_t status = I2C_OK;	
+		uint16_t timeout = TIMEOUT_TIMER_NOW_ADD(I2C_TIMEOUT);
+	
+
+		while (!(TWCR & (1<<TWINT)))
+		{
+			if(!(TIMEOUT_TIMER_LT(TIMEOUT_TIMER_NOW(), timeout)))
+			{
+				status = I2C_ERROR_TIMEOUT;
+				break;
+			}	
+		}
+	
+		return status;
+	}
+	
+	static int8_t wait_stop()
+	{
+		int8_t status = I2C_OK;	
+		uint16_t timeout = TIMEOUT_TIMER_NOW_ADD(I2C_TIMEOUT);
+	
+
+		while (TWCR & (1<<TWSTO))
+		{
+			if(!(TIMEOUT_TIMER_LT(TIMEOUT_TIMER_NOW(), timeout)))
+			{
+				status = I2C_ERROR_TIMEOUT;
+				break;
+			}	
+		}
+	
+		return status;
+	}
+#else
+	static int8_t wait_job()
+	{
+		while (!(TWCR & (1<<TWINT)));
+		return I2C_OK;
+	}
+	
+	static int8_t wait_stop()
+	{
+		while (TWCR & (1<<TWSTO));
+		return I2C_OK;
+	}
+#endif
+
+
+///////////////////////////////////////////////////////////////
+// member functions
+///////////////////////////////////////////////////////////////
+
+static int8_t i2c_ioctl(const i2c_driver* const me, uint8_t cmd, uint8_t arg)
+{
+	if(me == NULL || i2c_lock == false)
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_IOCTL__DEVICE_CLOSED);
+		return I2C_ERROR_DRIVER;
+	}
+		
+	if(cmd == I2C_IOCTL_CMD_SET_FREQ)
+	{
+		switch(arg)
+		{
+			case I2C_FREQ_400KHZ:	TWBR = I2C_FREQ_400KHZ; break;
+			case I2C_FREQ_250KHZ:	TWBR = I2C_FREQ_250KHZ; break;
+			case I2C_FREQ_100KHZ:	TWBR = I2C_FREQ_100KHZ; break;
+			case I2C_FREQ_50KHZ:	TWBR = I2C_FREQ_50KHZ; break;
+			case I2C_FREQ_10KHZ:	TWBR = I2C_FREQ_10KHZ; break;
+			default:
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_IOCTL__ARG_INVALID);
+				return I2C_ERROR_DRIVER;
+			}			
+		}
+	}
+	else
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_IOCTL__CMD_INVALID);
+		return I2C_ERROR_DRIVER;
+	}
+	
+	return I2C_OK;
+}
+
+static int8_t i2c_read(const i2c_driver* const me, uint8_t cmd_flags, uint8_t* buffer, uint8_t len)
+{
+	uint8_t i = 0;
+	int8_t status = I2C_OK;
+	
+	
+	if(me == NULL || i2c_lock == false)
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__DEVICE_CLOSED);
+		return I2C_ERROR_DRIVER;
+	}	
+	
+	if((len > 0) && (buffer == NULL))
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__ERROR_NULLPOINTER);
+		return I2C_ERROR_DRIVER;
+	}
+	
+	do 
+	{
+		if(cmd_flags & I2C_CMD_FLAG_START)
+		{
+			I2C_START();
+			if(wait_job() != I2C_OK)
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__START_TIMEOUT);
+				status = I2C_ERROR_TIMEOUT;
+				break;
+			}
+			if((I2C_STATUS() != I2C_STATUS_START) && (I2C_STATUS() != I2C_STATUS_START_REP))
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__START_ERROR);
+				status = I2C_ERROR_START;
+				break;
+			}
+			PRINTD("I2C-RD-START\n");
+		}
+		
+		if(len == 0) break;
+		
+		for(i=0; i<(len-1); i++)
+		{
+			I2C_READ_BYTE_ACK();
+			if(wait_job() != I2C_OK)
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__READ_BYTE_ACK_TIMEOUT);
+				status = I2C_ERROR_TIMEOUT;
+				break;
+			}
+			if(I2C_STATUS() != I2C_STATUS_DATAR_ACK)
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__READ_BYTE_ACK_ERROR);
+				status = I2C_ERROR_READ;
+				break;
+			}
+			buffer[i] = I2C_RX_REG;
+			PRINTD("I2C-RD-RACK: 0x%02X\n", buffer[i]);
+		}
+		
+		I2C_READ_BYTE_NACK();
+		if(wait_job() != I2C_OK)
+		{
+			RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__READ_BYTE_NACK_TIMEOUT);
+			status = I2C_ERROR_TIMEOUT;
+			break;
+		}
+		if(I2C_STATUS() != I2C_STATUS_DATAR_NACK)
+		{
+			RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__READ_BYTE_NACK_ERROR);
+			status = I2C_ERROR_READ;
+			break;
+		}
+		buffer[i] = I2C_RX_REG;
+		PRINTD("I2C-RD-RNACK: 0x%02X\n", buffer[i]);
+		
+	} while (0);
+	
+	if(cmd_flags & I2C_CMD_FLAG_STOP)
+	{
+		I2C_STOP();
+		if(wait_stop() != I2C_OK)
+		{
+			RTDEBUG_PUSH(RTDEBUG_CODE__I2C_READ__STOP_TIMEOUT);
+			status = I2C_ERROR_TIMEOUT;
+		}
+		PRINTD("I2C-RD_STOP\n");
+	}
+	
+	return status;
+}
+
+static int8_t i2c_write(const i2c_driver* const me, uint8_t cmd_flags, const uint8_t* data, uint8_t len)
+{
+	uint8_t i = 0;
+	int8_t status = I2C_OK;
+	
+	
+	if(me == NULL || i2c_lock == false)
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_WRITE__DEVICE_CLOSED);
+		return I2C_ERROR_DRIVER;
+	}
+	
+	if((len > 0) && (data == NULL))
+	{
+		RTDEBUG_PUSH(RTDEBUG_CODE__I2C_WRITE__ERROR_NULLPOINTER);
+		return I2C_ERROR_DRIVER;
+	}
+	
+	do 
+	{		
+		if(cmd_flags & I2C_CMD_FLAG_START)
+		{
+			I2C_START();
+			if(wait_job() != I2C_OK)
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_WRITE__START_TIMEOUT);
+				status = I2C_ERROR_TIMEOUT;
+				break;
+			}
+			if((I2C_STATUS() != I2C_STATUS_START) && (I2C_STATUS() != I2C_STATUS_START_REP))
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_WRITE__START_ERROR);
+				status = I2C_ERROR_START;
+				break;
+			}
+			PRINTD("I2C-WR-START\n");
+		}
+		
+		
+	
+		for(i=0; i<len; i++)
+		{
+			I2C_TX_REG = data[i];
+			I2C_WRITE_BYTE();
+			if(wait_job() != I2C_OK)
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_WRITE__WRITE_BYTE_TIMEOUT);
+				status = I2C_ERROR_TIMEOUT;
+				break;
+			}
+			if((I2C_STATUS() != I2C_STATUS_DATAW_ACK) && (I2C_STATUS() != I2C_STATUS_SLAW_ACK) && (I2C_STATUS() != I2C_STATUS_SLAR_ACK))
+			{
+				RTDEBUG_PUSH(RTDEBUG_CODE__I2C_WRITE__WRITE_BYTE_ERROR);
+				status = I2C_ERROR_WRITE;
+				break;
+			}
+			PRINTD("I2C-WR-BYTE: 0x%02X\n", data[i]);
+		}
+
+	} while (0);
+	
+	if(cmd_flags & I2C_CMD_FLAG_STOP)
+	{
+		I2C_STOP();
+		if(wait_stop() != I2C_OK)
+		{
+			RTDEBUG_PUSH(RTDEBUG_CODE__I2C_WRITE__STOP_TIMEOUT);
+			status = I2C_ERROR_TIMEOUT;
+		}
+		PRINTD("I2C-WR-STOP\n");
+	}
+	
+	return status;
+}
diff --git a/platform/osd-merkur/dev/i2c.h b/platform/osd-merkur/dev/i2c.h
new file mode 100644
index 000000000..ea56b214d
--- /dev/null
+++ b/platform/osd-merkur/dev/i2c.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2014, Ingo Gulyas Intembsys
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ */
+
+ /**
+ * \file
+ *         I2C driver for ATMEGA128rfa1
+ *
+ * \author
+ *         Ingo Gulyas Intembsys
+ *         office@intembsys.at
+ *         www.intembsys.at
+ */
+ 
+
+#ifndef I2C_H_
+#define I2C_H_
+
+
+#include <stdint.h>
+
+////////////////////////////////////////////////////////////////////////////////////////////
+// CONFIGURATION SECTION:
+
+#define I2C_TD          0			// compiler switch: i2c testdriver code
+
+#define I2C_PORT            PORTD
+#define I2C_DDR             DDRD
+#define I2C_SCL_PIN         0
+#define I2C_SDA_PIN         1
+
+// END OF CONFIGURATION SECTION
+////////////////////////////////////////////////////////////////////////////////////////////
+
+#define I2C_INIT()          ({I2C_DDR &= ~((1<<I2C_SCL_PIN) | (1<<I2C_SDA_PIN)); I2C_PORT |= ((1<<I2C_SCL_PIN) | (1<<I2C_SDA_PIN));})
+#define I2C_DEINIT()        ({I2C_DDR &= ~((1<<I2C_SCL_PIN) | (1<<I2C_SDA_PIN)); I2C_PORT |= ((1<<I2C_SCL_PIN) | (1<<I2C_SDA_PIN));})
+
+#define I2C_FREQ_STANDARD I2C_FREQ_50KHZ
+
+#if F_CPU == 16000000UL
+	#define	I2C_FREQ_400KHZ  0x03
+	#define	I2C_FREQ_250KHZ  0x06
+	#define	I2C_FREQ_100KHZ  0x12
+	#define	I2C_FREQ_50KHZ   0x26
+	#define I2C_FREQ_10KHZ   0xC6
+#else
+	#error "NO I2C FREQUENCY DEFINED -> CHECK F_CPU SETTINGS!"
+#endif
+
+
+#define I2C_STATUS_REG        TWSR
+#define I2C_TX_REG            TWDR
+#define I2C_RX_REG            TWDR
+
+#define I2C_START()           (TWCR = (1<<TWINT) |(1<<TWSTA) | (1<<TWEN))
+#define I2C_STOP()            (TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO))
+#define I2C_WRITE_BYTE()      (TWCR = (1<<TWINT) | (1<<TWEN))
+#define I2C_READ_BYTE_ACK()   (TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA))
+#define I2C_READ_BYTE_NACK()  (TWCR = (1<<TWINT) | (1<<TWEN))
+#define I2C_STATUS()          (I2C_STATUS_REG & I2C_STATUS_MASK)
+
+#define I2C_STATUS_MASK       0xF8
+#define I2C_STATUS_START      0x08
+#define I2C_STATUS_START_REP  0x10
+#define I2C_STATUS_SLAW_ACK   0x18
+#define I2C_STATUS_DATAW_ACK  0x28
+#define I2C_STATUS_SLAR_ACK   0x40
+#define I2C_STATUS_DATAR_ACK  0x50
+#define I2C_STATUS_DATAR_NACK 0x58
+
+#define I2C_ADR_WR(adr)       ((adr<<1) & ~(1<<0))
+#define I2C_ADR_RD(adr)       ((adr<<1) | (1<<0))
+
+#define I2C_CMD_FLAG_NONE     0x00
+#define I2C_CMD_FLAG_START    (1<<0)
+#define I2C_CMD_FLAG_STOP     (1<<1)
+
+
+#define I2C_OK                0
+#define I2C_ERROR_DRIVER      -1
+#define I2C_ERROR_TIMEOUT     -2
+#define I2C_ERROR_START       -3
+#define I2C_ERROR_WRITE       -4
+#define I2C_ERROR_READ        -5
+
+
+#define I2C_IOCTL_CMD_SET_FREQ 0x01
+
+
+typedef struct i2c_driver i2c_driver;
+struct i2c_driver
+{
+	int8_t (*ioctl)(const i2c_driver* const me, uint8_t cmd, uint8_t arg);
+	int8_t (*read)(const i2c_driver* const me, uint8_t cmd_flags, uint8_t* buffer, uint8_t len);
+	int8_t (*write)(const i2c_driver* const me, uint8_t cmd_flags, const uint8_t* data, uint8_t len);
+};
+
+i2c_driver* i2c_open(void);
+void i2c_close(i2c_driver* const me);
+void i2c_reset(void);
+
+
+#endif /* I2C_H_ */