用51实现断电保护的程序，但断电后还是回到0开始加，麻烦哪位大哥帮忙看下程序那里有错误啊！！！
#include<reg52.h>#define uchar unsigned char
sbit scl=P3^4;
sbit sda=P3^5;
sbit H1=P2^0;
sbit H2=P2^1;
#define uchar unsigned char
#define uint unsigned int
uchar code table[]={0xc0,0xf9,0xa4,0xb0
,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e};
uchar num,a,shi,ge,aa;
void delay2(uint z)
{
uint x, y;
for(x=z;x>0;x--)
for(y=110;y>0;y--);
}
void display(uchar shi,uchar ge)
{
H1=0;
P0=table[shi];
delay2(10);
H2=1; //ΪʲÃǼÓÒ»¸ö»á±äµÃ²»Ò»ÑùÄØ//
H1=1;
H2=0;
P0=table[ge];
delay2(10);
H1=1; //ͬÉÏ°¡/?/
H2=1;
}
void delay()
{
; ;
}
void start()
{
sda=1;
delay();
scl=1;
delay();
sda=0;
delay();
}
void stop()
{
sda=0;
delay();
scl=1;
delay();
sda=1;
delay();
}
void init()
{
num=0;
TMOD=0X01;
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
ET0=1;
EA=1;
TR0=1;
sda=1;
delay();
scl=1;
delay();
}
void respons()
{
uchar i;
scl=1;
delay();
while((sda==1)&&(i<250))i++;
scl=0;
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 z)
{
uchar a, b;
for(a=z;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();
while(1)
{
if(a==20)
{
a=0;
num++;
if(num==99)
{num=0;}
write_add(23,num);
delay1(100);
aa=read_add(23);
P1=read_add(23);
shi=aa/10;
ge=aa%10 ;
}
display(shi,ge);
}
}
void timeo() interrupt 1
{
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
a++;
}
