液晶1602电子时钟程序的键盘加减程序

#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit dula=P2^6;
sbit wela=P2^7;
sbit rs=P3^5;
sbit lcden=P3^4;
sbit rd=P3^7;
sbit wr=P3^6;
uchar count,s1num;
char miao,shi,fen;
uchar code table[]=" 2008-8-08 MON";
uchar code table1[]=" 08:08:08";
void delay(uint z)
{
uint x,y;
for(x=z;x>0;x--)
for(y=110;y>0;y--);
}
void write_com(uchar com)
{
rs=0;
lcden=0;
P0=com;
delay(5);
lcden=1;
delay(5);
lcden=0;
}
void write_date(uchar date)
{
rs=1;
lcden=0;
P0=date;
delay(5);
lcden=1;
delay(5);
lcden=0;
}
void init()
{
// wr=0;
uchar num;
dula=0;
wela=0;
lcden=0;
// fen=59;
// miao=53;
// shi=23;
write_com(0x38);
write_com(0x0c);
write_com(0x06);
write_com(0x01);
write_com(0x80);
for(num=0;num<15;num++)
{
write_date(table[num]);
delay(5);
}
write_com(0x80+0x40);
for(num=0;num<12;num++)
{
write_date(table1[num]);
delay(5);
}
TMOD=0x01;
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
EA=1;
ET0=1;
TR0=1;
}
void write_sfm(uchar add,uchar date)
{
uchar shi,ge;
shi=date/10;
ge=date%10;
write_com(0x80+0x40+add);
write_date(0x30+shi);
write_date(0x30+ge);
}
void main()
{
wr=0;
init();
while(1);
}
void timer0() interrupt 1
{
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
count++;
if(count==18)
{
count=0;
miao++;
if(miao==60)
{
miao=0;
fen++;
if(fen==60)
{
fen=0;
shi++;
if(shi==24)
{
shi=0;
}
write_sfm(4,shi);
}
write_sfm(7,fen);
}
write_sfm(10,miao);

}
}
这个是个时钟程序 我想用键盘进行对秒 分 时 日期 进行调整 怎么编写程序