Hi,

I've edited the code in the write function. I may do wrong in sending the Write address?

#include <REG51F.H>
#include <stdio.h>
#include <INPUT_OUTPUT.h>
#include <delay1.h>

// Function declarations
void initRS(); 												
void initPort();											
void I2C_Init();
void I2C_Start();
void I2C_Restart();
void I2C_Stop();
void I2C_SendAck();
void I2C_SendNack();
bit I2C_Write(unsigned char Data);
unsigned char I2C_Read();
unsigned char I2C_GetAck();

#define SDA p1_0
#define SCL p1_1

//Main function
void main()
{
	initRS();
	initPort();
	I2C_Init();
	
	//unsigned char RxByte = 0;

	I2C_Start();
	I2C_Write(0x40);
	I2C_Write(0xAA);
	I2C_Write(0xF0);
	//I2C_Read();
	//I2C_SendAck();
	I2C_Stop();

	while(1)
	{
	}

}


//Function : I2C Write Byte	transfer 1 bytes

bit I2C_Write(unsigned char Data)
	{
	unsigned char i;		// Variable to be used in for loop
	
	for(i=0;i<8;i++)		// Repeat for every bit
	{
		SCL = 0;			// Make SCL pin low
		delay1();		    // Data pin should change it's value,
									      // when it is confirm that SCL is low

		if ((Data & 0x80) == 0)			  // Decimal = 128 
			SDA = 0;
		else
			SDA = 1;
			delay1();
		SCL = 1;
		Data<<=1;
		delay1();
		SCL = 0;			// All routines must exit with clock LOW or bus clear
	}
	
// Get ACK from slave

     //unsigned char i;	    // Variables to be used in for loop
	 SCL = 0;
	 delay1();
	 SDA = 1;
	 delay1();
	 SCL = 1;
	 delay1();
	 SCL = 0;
	 return SDA;
	}
	
		
		

/*//	Function : I2C Read Byte
	unsigned char I2C_Read()
	{
	unsigned char i, Data=0;
	for(i=0;i<8;i++)
	{
		SCL = 0;
		SCL = 1;
		delay1();  */
		/*if(SDA)
			Data |=1;
		if(i<7)
			Data<<=1;*/

		/*Data<<=1;
		if(SDA) data|=1;
	}
	SCL = 0;
	SDA = 1;
	return Data;
	}  */
		


// Function : To set initial values of SDA and SCL
void I2C_Init()
{
	SDA = 1;				// Set SDA pin HIGH
	SCL = 1;			    // Set SCL pin LOW
}

// Function : Master sending START condition, HIGH to LOW transition on SDA while SCL keeping high
void I2C_Start()
{
	SCL = 1;
	SDA = 1;
	delay1();
	SDA = 0;
	delay1();
	SCL =0;
	delay1();
}

void I2C_Restart()
{
	SDA = 1;
	delay1();
	SCL = 1;
	delay1();
	SDA = 0;
	delay1();
	SDA = 0; 		//Always exit with clock LOW
	delay1();
}

void I2C_Stop()
{
	SDA = 0;
	delay1();
	SCL = 1;
	delay1();
	SDA = 1 ;
	delay1();

}

void I2C_Ack()
{
	SDA = 0;
	SCL = 1;
	SCL = 0;
}

void I2C_Nack()
{
	SDA = 1;
	SCL = 1;
	SCL = 0;
}

// Initialize serial port 
void initRS ()
{
    SCON  = 0x50;		        // SCON: mode 1, 8-bit UART, enable rcvr      
    TMOD  = 0x20;               // TMOD: timer 1, mode 2, 8-bit reload        
    TH1   = 253;                // TH1:  reload value for 9600 baud @ 11.0592MHz   FDH
    TR1   = 1;                  // TR1:  timer 1 run                          
    TI    = 1;                 	// TI:   set TI to send first char of UART    
}

//Initialize port
void initPort()
{
	P1 = 0xFF;                 
	P2 = 0x00;
	P0 = 0x00;
}
 

Thanks.

Regards,