这是电路图，这是从这个项目中取得的文件里面有电路图和仿真文件：http://www.51hei.com/bbs/dpj-22586-1.html
下面是 i2c.c文件：
#include <reg52.h>
#include "i2c.h"
#include "delay_ms.h"
void delay()
{
;;
}
void i2cinit()//总线初始化
{
SDA = 1;
delay();
SCL = 1;
delay();
}
void start()//启动信号
{
SDA = 1;
SCL = 1;
delay();
SDA = 0;
delay();
}
void stop()//停止信号
{
SDA = 0;
delay();
SCL = 1;
delay();
SDA = 1;
delay();
}
void respons()//应答信号
{
unsigned char i = 0;
SCL = 1;
delay();
while(SDA == 1 && i < 255)//等待应答，过一段时间不应答退出循环
i++;
SCL = 0;
delay();
}
void writebyte(unsigned char date)//写一个字节
{
unsigned char i,temp;
temp = date;
for(i = 0; i < 8; i++)
{
temp <<= 1;//temp左移一位后高位进CY
SCL = 0;
delay();
SDA = CY;
delay();
SCL = 1;
delay();
}
SCL = 0;//应答信号中SCL = 1，所以这里要置0
delay();
SDA = 1;//用完要释放数据总线
delay();
}
unsigned char readbyte()//读一个字节
{
unsigned char i,k;
SCL = 0;
delay();
SDA = 1;
for(i = 0; i < 8; i++)
{
SCL = 1;
delay();
k = (k << 1) | SDA; //和最低位或，一位位送到K
SCL = 0;
delay();
}
delay();
return k;
}
void write_add(unsigned char address,unsigned char date)//向地址写一个字节数据
{
start();
writebyte(0xa0);//A0,A1,A2接地，AT24C02芯片地址为1010，送控制字为1010A2A1A0R/~W
respons();
writebyte(address);
respons();
writebyte(date);
respons();
stop();
}
unsigned char read_add(unsigned char address)//向地址读一个字节数据
{
unsigned char date;
start();
writebyte(0xa0);//A0,A1,A2接地，AT24C02芯片地址为1010，送控制字为1010A2A1A0R/~W
respons();
writebyte(address);
respons();
start();
writebyte(0xa1);//A0,A1,A2接地，AT24C02芯片地址为1010，送控制字为1010A2A1A0R/~W
respons();
date = readbyte();
stop();
return date;
}
//向地址写n个字节数据,数据存放在指针P指的数组中
void write_n_add(unsigned char * p,unsigned char address,unsigned char n)
{
unsigned char i;
for(i = 0; i < n; i++)
{
write_add((address + i),*(p + i));
delay_ms(20);//一定要适当延时，不然写不进去
}
}
//向地址读n个字节数据,数据存放在指针P指的数组中
void read_n_add(unsigned char * p,unsigned char address,unsigned char n)
{
unsigned char i;
for(i = 0; i < n; i++)
{
*(p + i) = read_add(address + i);
}
}