用液晶显示的时钟不能正确设置光标闪烁！

程序如下，按下into0键后显示情况如图（附件）

#include<reg52.h>
#include<51hei.h>
#define uchar unsigned char
#define uint unsigned int
uchar code table1[]=" 2012-04-23 TUR";
uchar code table2[]="    00:00:00";
sbit duan=P2^6;
sbit wei=P2^7;
sbit lcdrs=P3^5;
sbit lcden=P3^4;
//sbit key=P3^7;
sbit key1=P3^2;
sbit key2=P3^6;
sbit key3=P3^7;
uchar count,shi,fen,miao,keynum;

void delay(uint z)
{
 uint x,y;
 for(x=z;x>0;x--)
  for(y=110;y>0;y--);
}

void write_cmd(uchar cmd)
{
 lcdrs=0;
// lcden=0;
 P0=cmd;
 delay(5);
 lcden=1;
 delay(5);
 lcden=0;
}

void write_dat(uchar dat)
{
 lcdrs=1;
// lcden=0;
 P0=dat;
 delay(5);
 lcden=1;
 delay(5);
 lcden=0;
}

void init()
{
 uchar num;
 guandz();
 guanled();
 duan=0;
 wei=0;
 lcden=0;
 keynum=0;
// miao=59;
// fen=58;
// shi=23;
 write_cmd(0x38);
 write_cmd(0x0c);
 write_cmd(0x06);
 write_cmd(0x01);
 write_cmd(0x80);
 for(num=0;num<15;num++)
 {
  write_dat(table1[num]);
  delay(20);
 }
 write_cmd(0x80+40);
 for(num=0;num<12;num++)
 {
  write_dat(table2[num]);
  delay(20);
 }
 TMOD=0X01;
 TH0=(65536-50000)/256;
 TL0=(65536-50000)%256;
 EA=1;
 ET0=1;
 TR0=1;
}

void write_sfm(uchar add,uchar dat)
{
 uchar shi,ge;
 shi=dat/10;
 ge=dat%10;
 write_cmd(0x80+0x40+add);
 write_dat(0x30+shi);
 write_dat(0x30+ge);
}

void keyscan()
{
// key=0;
 if(key1==0)
 {
  delay(5);
  if(key1==0)
  {
   keynum++;
   while(!key1);
   if(keynum==1)
   {
    TR0=0;
    write_cmd(0x80+0x40+11);
    write_cmd(0x0f);
   }
   if(keynum==2)
   {
    write_cmd(0x80+0x40+8);
   }
   if(keynum==3)
   {
    write_cmd(0x80+0x40+5);
   }
   if(keynum==4)
   {
    keynum=0;
    write_cmd(0x0c);
    TR0=1;
   }
  }
 }
}

void main()
{
 init();

 while(1)
 {
  keyscan();
  if(count==20)
  {
   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);
 }
}

void timer0() interrupt 1
{
 TH0=(65536-50000)/256;
 TL0=(65536-50000)%256;
 count++;
}