24c02掉电保护求一个具体的程序

......
24c02是串行I2 C总线EEPROM
写进去的掉电后数据不会丢失。
#include
#define uchar unsigned char
sbit sda=P2^0;
sbit scl=P2^1;
uchar a;
void delay()
{ ; ; }
void start() //开始信号
{
sda=1;
delay();
scl=1;
delay();
sda=0;
delay();
}

void stop() //停止
{
sda=0;
delay();
scl=1;
delay();
sda=1;
delay();
}

void respons() //应答
{
uchar i;
scl=1;
delay();
while((sda==1)&&(i<250))i++;
scl=0;
delay();
}

void init()
{
sda=1;
delay();
scl=1;
delay();
}

void write_byte(uchar date)
{
uchar i,temp;
temp=date;
for(i=0;i<8;i++)
{
temp=temp<<1;
scl=0;
delay();
sda=CY;
delay();
scl=1;
delay();
}
scl=0;
delay();
sda=1;
delay();
}

uchar read_byte()
{
uchar i,k;
scl=0;
delay();
sda=1;
delay();
for(i=0;i<8;i++)
{
scl=1;
delay();
k=(k<<1)|sda;
scl=0;
delay();
}
return k;
}

void delay1(uchar x)
{
uchar a,b;
for(a=x;a>0;a--)
for(b=100;b>0;b--);
}

void write_add(uchar address,uchar date)
{
start();
write_byte(0xa0);
respons();
write_byte(address);
respons();
write_byte(date);
respons();
stop();
}

uchar read_add(uchar address)
{
uchar date;
start();
write_byte(0xa0);
respons();
write_byte(address);
respons();
start();
write_byte(0xa1);
respons();
date=read_byte();
stop();
return date;
}

void main()
{
init();
write_add(23,0xaa);
delay1(100);
P1=read_add(23);
while(1);
}