diff --git a/firmware/slavechip/i2c_simple.c b/firmware/slavechip/i2c_simple.c
index 9b1dd7d..4523863 100644
--- a/firmware/slavechip/i2c_simple.c
+++ b/firmware/slavechip/i2c_simple.c
@@ -5,33 +5,34 @@
 
 #include "i2c_simple.h"
 
+#define I2C_WAIT() while(!(TWCR & _BV(TWINT)))
+
 void i2c_init()
 {
 	TWBR = 32;//bit rate
 	TWSR = 0;//Prescaler
 	
-	TWAR = 0x80;//our address 1000 000, don't listen to general call
-	TWAMR = 0;
+//	TWAR = 0x80;//our address 1000 000, don't listen to general call
+//	TWAMR = 0;
 	
-	TWCR = TWEA | TWEN;/* TWINT clear -> we must do something; unset TWSTA manually!, TWSTO */
+	TWCR = _BV(TWEA) | _BV(TWEN);/* _BV(TWINT) clear -> we must do something; unset _BV(TWSTA) manually!, _BV(TWSTO) */
 	//TWDR - data
 }
 
 uint8_t i2c_read(uint8_t addr, uint8_t len, uint8_t *data)
 {
-	TWCR &= ~TWSTO;
-	TWCR |= TWINT | TWSTA;
-	while(~TWCR & TWINT) {;}/* get bus access */
+	TWCR |= _BV(TWINT) | _BV(TWSTA);
+	I2C_WAIT();
 	/* no error possible */
 	
 	TWDR = addr | 1;
-	TWCR &= ~(TWSTA | TWSTO);
-	TWCR |= TWINT;
-	while(~TWCR & TWINT) {;}/* transmit address */
+	TWCR &= ~(_BV(TWSTA));
+	TWCR |= _BV(TWINT);
+	I2C_WAIT();
 	/* possible results: ACK, NAK, abitration lost */
 	if(TW_STATUS == TW_MR_SLA_NACK)
 	{
-		TWCR |= TWINT | TWSTO;
+		TWCR |= _BV(TWINT) | _BV(TWSTO);
 		return 0;
 	}
 	else if(TW_STATUS == TW_MR_ARB_LOST) {return 0;}
@@ -39,37 +40,36 @@ uint8_t i2c_read(uint8_t addr, uint8_t len, uint8_t *data)
 	uint8_t done = 0;
 	while(done + 1 < len)
 	{
-		TWCR |= TWEA | TWINT;/* send ack after byte */
-		while(~TWCR & TWINT) {;}/* read data */
+		TWCR |= _BV(TWEA) | _BV(TWINT);/* send ack after byte */
+		I2C_WAIT();
 		data[done] = TWDR;
 		done++;
-		TWCR |= TWINT;
+		TWCR |= _BV(TWINT);
 	}
 	
-	TWCR &= ~TWEA;
-	TWCR |= TWINT;/* send nak after byte */
-	while(~TWCR & TWINT) {;}/* read data */
+	TWCR &= ~_BV(TWEA);
+	TWCR |= _BV(TWINT);/* send nak after byte */
+	I2C_WAIT();
 	data[done] = TWDR;
 	done++;
-	TWCR |= TWINT | TWSTO;
+	TWCR |= _BV(TWINT) | _BV(TWSTO);
 	return done;
 }
 
 uint8_t i2c_write_i(uint8_t addr, uint8_t len, uint8_t *data, uint8_t stop)
 {
-	TWCR &= ~TWSTO;
-	TWCR |= TWINT | TWSTA;
-	while(~TWCR & TWINT) {;}/* get bus access */
+	TWCR |= _BV(TWINT) | _BV(TWSTA);
+	I2C_WAIT();
 	/* no error possible */
 	
 	TWDR = addr;
-	TWCR &= ~(TWSTA | TWSTO);
-	TWCR |= TWINT;
-	while(~TWCR & TWINT) {;}/* transmit address */
+	TWCR &= ~(_BV(TWSTA));
+	TWCR |= _BV(TWINT);
+	I2C_WAIT();
 	/* possible results: ACK, NAK, abitration lost */
 	if(TW_STATUS == TW_MT_SLA_NACK)
 	{
-		TWCR |= TWINT | TWSTO;
+		TWCR |= _BV(TWINT) | _BV(TWSTO);
 		return 0;
 	}
 	else if(TW_STATUS == TW_MT_ARB_LOST) {return 0;}
@@ -78,19 +78,19 @@ uint8_t i2c_write_i(uint8_t addr, uint8_t len, uint8_t *data, uint8_t stop)
 	while(done < len)
 	{
 		TWDR = data[done];
-		TWCR |= TWINT;
-		while(~TWCR & TWINT) {;}/* write data */
+		TWCR |= _BV(TWINT);
+		I2C_WAIT();
 		/* possible results: ACK, NAK, abitration lost */
 		if(TW_STATUS == TW_MT_DATA_NACK)
 		{
-			TWCR |= TWINT | TWSTO;
+			TWCR |= _BV(TWINT) | _BV(TWSTO);
 			return done;
 		}
 		else if(TW_STATUS == TW_MT_ARB_LOST) {return done;}
 		done++;
 	}
 	
-	if(stop) {TWCR |= TWINT | TWSTO;}
+	if(stop) {TWCR |= _BV(TWINT) | _BV(TWSTO);}
 	return done;
 }