#include<AT89X51.h>
unsigned char code dispcode[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x40};//共陰極
unsigned char dispbitcode[]={0x00,0x21,0x42,0x63,0x84,0xA5,0xC6,0xE7};//管子的選擇
unsigned char dispbuf[8]={0,0,10,0,0,10,2,1};   //16為顯示間斷號符
unsigned char dispbym[8]={1,2,7,0,6,0,0,2};
unsigned char dispbitcnt;
unsigned char second;
unsigned char minite;
unsigned char hour;
unsigned char day;
unsigned char month;
unsigned char yearh;
unsigned char yearl;
unsigned int tcnt;
unsigned char mstcnt;
unsigned char i,j;
void main(void)
{
 TMOD=0x02;                    //設置模式為定時器T0的模式2 （8位自動重裝計數初值的計數值）        
 TH0=0x06;                     //設置計數器初值，靠TH0存儲重裝的計數值X0=256-250=6
 TL0=0x06;
 TR0=1;                //啟動T0
 ET0=1;                //開啟定時器T0中斷允許
 EA=1;                 //開啟中斷總控制
 yearh=20;
 yearl=6;
 month=7;
 day=21;
 hour=12;              //初始值為12:00:00
 while(1)	
 {
  if(P0_0==0)                //掃描秒鐘按鈕
  {
   for(i=5;i>0;i--)            //按鈕抖動消除
   for(j=248;j>0;j--);       //計時
   if(P0_0==0)
   {
    second++;
    if(second==60)
    {
     second=0;
    }
    dispbuf[0]=second%10;
    dispbuf[1]=second/10;
    while(P0_0==0);
   }
  }

  if(P0_1==0)             //掃描分鐘按鈕
  {
   for(i=5;i>0;i--)       
   for(j=248;j>0;j--);
   if(P0_1==0)
   {
    minite++;
    if(minite==60)
    {
     minite=0;
    }
    dispbuf[3]=minite%10;
    dispbuf[4]=minite/10;
    while(P0_1==0);
   }
  }

  if(P0_2==0)           //掃描時鐘按鈕
  {
   for(i=5;i>0;i--)
   for(j=248;j>0;j--);
   if(P0_2==0)
   {
    hour++;
    if(hour==24)
    {
     hour=0;
    }
    dispbuf[6]=hour%10;
    dispbuf[7]=hour/10;
    while(P0_2==0);
   }
  }
 
  if(P0_3==0)
  {
   for(i=5;i>0;i--)
   for(j=248;j>0;j--);
   if(P0_3==0)
   {
    day++;
    if(month==2&&((yearl==0&&yearh%4==0)||(yearl!=0&&yearl%4==0))&&day==30)day=1;  
    else if(month==2&&day==29)day=1;
    else if((month==4||month==6||month==9||month==11)&&day==31)day=1;
    else if(day==32)day=1;
    dispbym[0]=day%10;
    dispbym[1]=day/10;
    while(P0_3==0);
   }
  }

  if(P0_4==0)
  {
   for(i=5;i>0;i--)
   for(j=248;j>0;j--);
   if(P0_4==0)
   {
    month++;
    if(month==13)month=1;
    dispbym[2]=month%10;
    dispbym[3]=month/10;
    while(P0_4==0);
   }
  }

  if(P0_5==0)
  {
   for(i=5;i>0;i--)
   for(j=248;j>0;j--);
   if(P0_5==0)
   {
    yearl++;
    if(yearl==100)
    {
     yearl=0;
     yearh++;
     if(yearh==100)yearh=20;
    }
    dispbym[4]=yearl%10;
    dispbym[5]=yearl/10;
    dispbym[6]=yearh%10;
    dispbym[7]=yearh/10;
    while(P0_5==0);
   }
  }

 }
}

void t0(void)interrupt 1 using 0   //t0的中斷程序
{
 mstcnt++;
 if(mstcnt==8)                    //8次250us為2ms,即每隔2ms掃描一個數碼管
 {
  mstcnt=0;
  P1=dispcode[dispbuf[dispbitcnt]];
  P2=dispcode[dispbym[dispbitcnt]];
  P3=0xff;
  P3=dispbitcode[dispbitcnt];          //管子的選擇
  dispbitcnt++;                    
  if(dispbitcnt==8)
  {
   dispbitcnt=0;
  }
 }
 tcnt++;
 if(tcnt==4000)                    //定時器的定時計數，4000次250us為1秒
 {
  tcnt=0;
  second++;
  if(second==60)                  //從秒到時層層嵌套，程序較為精練
  {
   second=0;
   minite++;
   if(minite==60)
   {
    minite=0;
	hour++;
	if(hour==24)
	{
	 hour=0;
	 day++;
	 if(month==2&&((yearl==0&&yearh%4==0)||(yearl!=0&&yearl%4==0))&&day==30)day=1;  
     else if(month==2&&day==29)day=1;
     else if((month==4||month==6||month==9||month==11)&&day==31)day=1;
     else if(day==32)day=1;
	 if(day==1)
     {
	  month++;
	  if(month==13)
	  {
	   month=1;
	   yearl++;
	   if(yearl==100)
	   {
	    yearl=0;
	    yearh++;
		if(yearh==100)
		{
		 yearh=20;
		}
	   }
	  }
	 }
	}
   }
  }
  dispbuf[0]=second%10;          //送顯示數據
  dispbuf[1]=second/10;

  dispbuf[3]=minite%10;
  dispbuf[4]=minite/10;

  dispbuf[6]=hour%10;
  dispbuf[7]=hour/10;

  dispbym[0]=day%10;
  dispbym[1]=day/10;

  dispbym[2]=month%10;
  dispbym[3]=month/10;

  dispbym[4]=yearl%10;
  dispbym[5]=yearl/10;

  dispbym[6]=yearh%10;
  dispbym[7]=yearh/10;
 }
}