这是主程序
#include "msp430f5438.h"
#include "IIC.H"

void main( void )
{ 
  WDTCTL = WDTPW + WDTHOLD                                ;
  init_IIC();
  send_IIC(255);
  delay_us(2);
  STOP_IIC();
  while(1);  
}

这是IIC.C
#include "IIC.H"
#include "msp430x54x.h"

#define SDA_H                  P2OUT  |= BIT0;
#define SDA_L                  P2OUT  &= ~BIT0;

#define SCK_H                  P2OUT  |= BIT1;
#define SCK_L                  P2OUT  &= ~BIT1;

#define SDA_send               P2DIR  |= 0xff;
#define SDA_receive            P2DIR  &= 0xfe;

#define SDA_IN                 P1IN;

unsigned char receive_success = 0;

void delay_us(unsigned char a)
{
  while(a--);
}
void START_IIC(void)
{
  SDA_H;
  SCK_H;
  delay_us(100);
  SDA_L;
  delay_us(20);
}

void STOP_IIC(void)
{
  SDA_L;
  SCK_H;
  delay_us(100);
  SDA_L;
  delay_us(20);
}

unsigned char send_IIC(unsigned char data)
{
  unsigned char i;
  for(i=0;i<=8;i++)
  {
    if(i == 8)
    {
      SDA_receive;
      SCK_H;
      SCK_L;
      delay_us(2);
      if(P1IN&&0xfe)
        receive_success = 1;
      else 
        receive_success = 0;
      SDA_send;
      break;  
    }
    else
    {
      SDA_send;
      SCK_H;
      if(data&0x80)
        SDA_H; 
      if((data&0x80) == 0)
        SDA_L;
      SCK_L;
      delay_us(1);
      data <<= 1;
    }
  }
}

void init_IIC()
{
  SDA_send;
  START_IIC();
  send_IIC(0x98);
  delay_us(1);
  send_IIC(0x90);
  delay_us(1);
  send_IIC(0x00);
  delay_us(1);
}


这是IIC.H
#ifndef __IIC_H__
#define __IIC_H__
#include "msp430x54x.h"

void START_IIC(void);
void STOP_IIC(void);
unsigned char send_IIC(unsigned char data);

#endif