diff --git a/Control/firmware/uart_echo/main.c b/Control/firmware/uart_echo/main.c
index 4c02925..ffec580 100755
--- a/Control/firmware/uart_echo/main.c
+++ b/Control/firmware/uart_echo/main.c
@@ -110,6 +110,85 @@ void timer_init()
 	
 }
 
+enum I2C
+{
+	I2C_START = 0x08,
+	I2C_REPEATED_START = 0x10,
+	I2C_SLA_ACK = 0x18,
+	I2C_SLA_NACK = 0x20,
+	I2C_DATA_ACK = 0x28,
+	I2C_DATA_NACK = 0x30,
+	I2C_LOST = 0x38,
+	I2C_READ = 0x01,
+	I2C_WRITE = 0x00
+};
+
+void i2c_init()
+{
+	TWBR = 0xFF;
+	TWSR = 0x03;
+}
+
+void i2c_send(uint8_t addr, uint8_t rw, uint8_t *data, size_t size)
+{
+	TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);
+									// Send START condition
+	do 
+	{
+		while (!(TWCR &(1<<TWINT)));	// Wait for TWINT Flag set. This indicates
+										// that the START condition has been
+										// transmitted.	
+		if((TWSR & 0xF8) != I2C_START)
+		{
+			printf("Error I2C_START\n");
+			break;
+		}
+		TWDR = addr<<1 | rw;					// Load SLA_W into TWDR Register. Clear
+										// TWINT bit in TWCR to start transmission of
+										// address.
+		TWCR = (1<<TWINT) | (1<<TWEN);									
+		while (!(TWCR &(1<<TWINT)));	// Wait for TWINT Flag set. This indicates
+										// that the SLA+W has been transmitted, and
+										// ACK/NACK has been received.
+
+
+		if ((TWSR & 0xF8) != I2C_SLA_ACK)
+		{
+			printf("Error I2C_SLA_ACK\n");
+			break;
+		}
+										// Check value of TWI Status Register. Mask
+										// prescaler bits. If status different from
+										// MT_SLA_ACK go to ERROR
+		for (size_t i=0; i < size; i++)
+		{
+			
+			TWDR = *(data++);
+			TWCR = (1<<TWINT) | (1<<TWEN);
+											// Load DATA into TWDR Register. Clear
+											// TWINT bit in TWCR to start transmission of
+											// data.
+
+			while (!(TWCR & (1<<TWINT)));
+											// Wait for TWINT Flag set. This indicates
+											// that the DATA has been transmitted, and
+											// ACK/NACK has been received}
+
+			if ((TWSR & 0xF8) != I2C_DATA_ACK)
+			{
+				printf("Error I2C_DATA_ACK\n");
+				break;
+			}
+											//	Check value of TWI Status Register. Mask
+											//	prescaler bits. If status different from
+											//	MT_DATA_ACK go to ERROR.
+		}
+	
+	} while (0);
+	TWCR = (1<<TWINT)| (1<<TWEN)|(1<<TWSTO);	// Transmit STOP condition.
+
+}
+
 void adc_init()
 {
 	PRR &= ~(1 << PRADC);
@@ -125,8 +204,8 @@ void adc_start_conversion(int ch)
 int adc_is_fininshed()
 {
 	return (int)(0 == (ADCSRA & (1 << ADSC)));
-	
 }
+
 int16_t adc_read()
 {
 	return adc_value;
@@ -177,6 +256,7 @@ void port_init()
 }
 FILE uart_file = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
 
+
 int main(void)
 {
 	
@@ -184,10 +264,14 @@ int main(void)
 	uart_init();
 	timer_init();
 	adc_init();
+	i2c_init();
 	
 	stdout = &uart_file;
 	printf("UART test version 1.0\n\n");
-	
+
+	uint8_t write_dac_full[] = {0x40, 0x00, 0x00};		// 6.1 Write Volatile DAC Register (C2:C0 = ‘00x’)
+	i2c_send(0x60, I2C_WRITE, write_dac_full, sizeof(write_dac_full));
+
 	sei();
 	adc_start_conversion(adc_ch);
 	while (1) 
@@ -196,15 +280,21 @@ int main(void)
 		if (msgCode)
 		{
 			cli();
-			switch(msgCode)
+			uint8_t _msgCode = msgCode;
+			uint8_t _msgData = msgData;
+			sei();
+			
+			switch(_msgCode)
 			{
 				case Command:
-				printf("Command : %c\n", msgData);
+				printf("Command : %c\n", _msgData);
+				uint8_t write_dac[] = {0x00+(_msgData-'0'), 0x00};					// 6.2 Write Volatile Memory (C2:C0 = ‘010’)
+				i2c_send(0x60, I2C_WRITE, write_dac, sizeof(write_dac));
 				break;
 			
 				case AdcComplete:
 				{
-					size_t ch = msgData;
+					size_t ch = _msgData;
 					if (ch == 6)
 					{
 						printf("ADC=%d\n", adc_value[ch]);
@@ -235,8 +325,6 @@ int main(void)
 				printf("Error!!!\n");
 				break;
 			}
-			msgCode = NOP;
-			sei();
 		}
     }
 }