MSP430 IIC bus program

#ifndef _I2C_H
#define _I2C_H
#define SDA_1      P4OUT|=0x02               //SDA = 1
#define SDA_0      P4OUT&=~0x02              //SDA = 0
#define SCL_1      P4OUT|=0x01               //SCL = 1
#define SCL_0      P4OUT&=~0x01              //SCL = 0
#define SDA_IN      P4DIR&=~0x02;            //I/O port is input
#define SDA_OUT     P4DIR|=0x02               //I/0 port is output
#define J_SDA_1_or_0   (P4IN&0x02)==0x02
//--------------------------------------------
//--------The following is the 24C64 read and write sub-function
//DELAY Function program //Function: delay subroutine
//==============================================
static void Delay(unsigned int n)
{
while(n!=0)
{n--;}
}
//===========================================
//START Function program
//Function: start flash memory operation
/==============================================
void Start(void)
{
  SDA_OUT;
  SDA_1;
  Delay(10);
  SCL_1;
  Delay(10);
  SDA_0;
  Delay(10);
  SCL_0;
  Delay(10);
}
//===========================================
//STOP function program
//Function: stop flash memory operation
//===============================================
void Stop(void)
{
  SDA_0;
  Delay(10);
  SCL_1;
  Delay(10);
  SDA_1;
  Delay(10);
}

void TX_Byte(unsigned char WriteData)
{
  unsigned char i,j;
  j=WriteData;
  SDA_OUT;
  for (i=0; i<8; i++)
  {
   if ((j&0x80)==0)
   { SDA_0;}
   else
   { SDA_1;}
   j <<=1;
   Delay(10);
   SCL_1;
   Delay(10);
   SCL_0;
   Delay(10);
  }
}

unsigned char RX_Byte(void)
{
  unsigned char i;
  unsigned char TempData = 0;
  SDA_IN;
  for (i=0; i<8; i++)
  {
   Delay(10);
   SCL_1;
   Delay(10);
   TempData <<= 1;
   if (J_SDA_1_or_0)
   { TempData++; }
   SCL_0;
   Delay(10);
  }
  SDA_OUT;
  return(TempData);
}
//===========================================
//ACK function program
//Function: high level indicates flash memory clock signal
//==============================================
void ReceiveAck(void)
{
  SDA_IN;
  SCL_1;
  Delay(10);
  while (J_SDA_1_or_0)
  {   }
  SCL_0;
  SDA_OUT;
  Delay(10);
}

unsigned char ReadWord(unsigned long int unit)
{
  unsigned char LowAdd  = 0;
  unsigned char HighAdd = 0;
  unsigned char  TempData = 0;
  LowAdd  = (unsigned char)unit;
  HighAdd = (unsigned char)(unit >> 8);
  SDA_OUT;
  Start();
  TX_Byte(0xa0);
  ReceiveAck();
  TX_Byte(HighAdd);
  ReceiveAck();
  TX_Byte(LowAdd);
  ReceiveAck();
  Start();
  TX_Byte(0xa1);
  ReceiveAck();
  TempData  = RX_Byte();  
  Stop();
  Delay(8000);  
  return(TempData);
}

void WriteWord(unsigned long int unit, unsigned char WriteData)
{
  unsigned char LowAdd  = 0;
  unsigned char HighAdd = 0;
  LowAdd  = (unsigned char)unit;
  HighAdd = (unsigned char)(unit >> 8);
  Start();
  TX_Byte(0xa0);
  ReceiveAck();
  TX_Byte(HighAdd);
  ReceiveAck();
  TX_Byte(LowAdd);
  ReceiveAck();
  TX_Byte(WriteData);
  ReceiveAck();
  Stop();
  Delay(8000);
}
#endif