/*用動態掃描方法和定時器在數碼管的前三位顯示出秒表，
精確到%1秒，即后兩位顯示%1秒，一直顯循環下去。*/
#include<reg52.h>
#define uc unsigned char
sbit duans=P2^6;
sbit weis=P2^7;
uc count,i,j;
unsigned int num;
uc code table[]={
0x3f,0x06,0x5b,0x4f,
0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,
0x39,0x5e,0x79,0x71};
uc code table1[]={
0xbf,0x86,0xdb,0xcf,
0xe6,0xed,0xfd,0x87,
0xff,0xef};
display(uc,uc,uc);
delay(uc);
void main()
{
	EA=1;
	ET1=1;
	TMOD=0x10;
	TH1=(65536-5000)/256;
	TL1=(65536-5000)%256;
	TR1=1;
	
	while(1)
	  {
       	
        if(count==2)//控制數字變化的速度
         {
		  count=0;
		  if(num==1000)
			  num=0;
          num++;
		  }
         display(num/100,num%100/10,num%100%10);
	   }
}
void time1() interrupt 3 using 1
{
	TH1=(65536-5000)/256;
	TL1=(65536-5000)%256;	
    count++;
 
}
display(uc bai,uc shi,uc ge)
{
P0=0xff;//消除余輝
weis=1;
weis=0;

P0=table1[bai];
duans=1;
duans=0;
P0=0xfe;
weis=1;
weis=0;
delay(1);//控制動態掃描的時間

P0=0xff;
weis=1;
weis=0; 

P0=table[shi];
duans=1;
duans=0;
P0=0xfd;
weis=1;
weis=0;
delay(1);

P0=0xff;
weis=1;
weis=0;

P0=table[ge];
duans=1;
duans=0;
P0=0xfb;
weis=1;
weis=0;
delay(1);
}
delay(uc x)
{
	for(i=20;i>0;i--)
 	for(j=x;j>0;j--);
}