51单片机模拟I2C总线程序

#include
#include
sbitled=P1^0;
sbitled2=P1^1;
sbit scl=P3^5;//24c02 SCL
sbit sda=P3^4;//24c02 SDA
sbit DOG=P1^7;//狗
uchar x24c02_read(uchar address);

//从24c02的地址address中读取一个字节数据
void x24c02_write(uchar address,uchar info);
//向24c02的address地址中写入一字节数据info
void x24c02_init();//24c02初始化子程序
void delay1(uchar x);
void flash();
void x24c01_init();
void start();
void stop();
void writex(uchar j);
uchar readx();
void clock();
void delay1(uchar x)
{
uint i;
for(i=0;iDOG=~DOG;
}
void flash()
{
uchar u;
DOG=~DOG;
}
void x24c02_init()
{
scl=1; flash(); sda=1; flash();
}
void start()
{
sda=1; flash(); scl=1; flash(); sda=0; flash(); scl=0; flash();
}
void stop()
{
sda=0; flash(); scl=1; flash(); sda=1; flash();
}
void writex(uchar j)
{
uchar i,temp;
temp=j;
for (i=0;i<8;i++){
temp=temp<<1; scl=0; flash(); sda=CY; flash(); scl=1; flash();
}
scl=0; flash(); sda=1; flash();
}
uchar readx()
{
uchar i,j,k=0;
scl=0; flash(); sda=1;
for (i=0;i<8;i++){
flash(); scl=1; flash();
if (sda==1) j=1;
else j=0;
k=(k<<1)|j; scl=0;
}
flash(); return(k);
}
void clock()
{
uchar i=0;
scl=1; flash();
while ((sda==1)&&(i<255))i++;
scl=0; flash();
}
uchar x24c02_read(uchar address)
{
uchar i;
start(); writex(0xa0);
clock(); writex(address);
clock(); start();
writex(0xa1); clock();
i=readx(); stop();
delay1(10);
return(i);
}
void x24c02_write(uchar address,uchar info)
{
EA=0;
start(); writex(0xa0);
clock(); writex(address);
clock(); writex(info);
clock(); stop();
EA=1;
delay1(50);
}


//====================================================================//
main(){
uchar data a=2,b=10,c=0;
x24c02_init();
x24c02_write(a,b);
delay1(200);
c=x24c02_read(a);

if(c==b)led=0;
led2=0;

}
//===================================================================//
//==========================================================