diff --git a/firmware/Makefile b/firmware/Makefile
index a8fbe3f..4493978 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -4,7 +4,7 @@ CFLAGS += -std=gnu99 # implements C99, for <util/atomic.h>
 # this removes dead code and does global linker optimization
 #CFLAGS += -ffunction-sections -Wl,--gc-sections -Wl,--relax 
 
-OBJECTS = usbdrv/usbdrvasm.o  usbdrv/usbdrv.o main.o display.o lcd/lcd.o mcp_adc.o 
+OBJECTS = usbdrv/usbdrvasm.o  usbdrv/usbdrv.o main.o display.o lcd/lcd.o mcp_adc.o i2c_simple.o
 
 
 
diff --git a/firmware/i2c_simple.c b/firmware/i2c_simple.c
new file mode 100644
index 0000000..f946064
--- /dev/null
+++ b/firmware/i2c_simple.c
@@ -0,0 +1,23 @@
+
+#include <stdint.h>
+
+#include "i2c_simple.h"
+
+
+
+void i2c_init(){
+    //TODO: implement
+}
+
+uint8_t i2c_read(uint8_t addr, uint8_t len, uint8_t *data){
+    return 0; //TODO: implement
+}
+
+uint8_t i2c_write(uint8_t addr, uint8_t len, uint8_t *data){
+    return 0; //TODO: implement
+}
+
+uint8_t i2c_write_read(uint8_t addr, uint8_t writelen, uint8_t* writedata, uint8_t readlen, 
+        uint8_t* readdata){
+    return 0; //TODO: implement
+}
diff --git a/firmware/i2c_simple.h b/firmware/i2c_simple.h
new file mode 100644
index 0000000..c7aee5f
--- /dev/null
+++ b/firmware/i2c_simple.h
@@ -0,0 +1,17 @@
+
+
+
+
+
+/* initializes i2c interface (master, 400kHz) */
+void i2c_init();
+
+/* reads len bytes from the i2c device addr into data */
+uint8_t i2c_read(uint8_t addr, uint8_t len, uint8_t *data);
+
+/* writes to an i2c device */
+uint8_t i2c_write(uint8_t addr, uint8_t len, uint8_t *data);
+
+/* writes, followed by a repeated start and a read */
+uint8_t i2c_write_read(uint8_t addr, uint8_t writelen, uint8_t* writedata, uint8_t readlen, 
+        uint8_t* readdata);
diff --git a/firmware/mcp_adc.c b/firmware/mcp_adc.c
index 04e0f83..d6d04cb 100644
--- a/firmware/mcp_adc.c
+++ b/firmware/mcp_adc.c
@@ -1,5 +1,9 @@
 #include <stdint.h>
 
+#include "i2c_simple.h"
+
+#include "mcp_adc.h"
+
 /* analog digital converter
  * scratchpad
  * 
@@ -43,7 +47,7 @@ int32_t mcpadc_get_data()
 	value = (value << 16) | (r[0] << 8) | r[1];/*endianess ???*/
 	if((uint8_t) r[3] & ADC_BITS_MASK == ADC_BITS_18)
 	{
-		value = (value << 8) | r[3];
+		value = (value << 8) | r[2];
 	}
 	return value;
 }
@@ -52,7 +56,7 @@ int16_t mcpadc_get_data()
 {
 	i2c_read(ADC_ADDR, 2, r);/* this will NOT work in 18 bit mode */
 	int16_t value = (r[0] << 8) | r[1];/*endianess ???*/
-	return r;
+	return value;
 }
 #endif