#include
#include

void somenop()
{
 uchar i=5;
 while(i--)
 {
  _nop_();
 }
}

//8位扫描显示，共阳数码管
uchar shum[]={
              0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
void delaym()
{
 uchar i;
 for(i=0;i<0xff;i++);
 
}

void init();
void star();
void stop();
void ack();
void write_byte(uchar date);
uchar read_byte();
sbit scl=P1^2;
sbit sda=P1^3;
uchar sec,min=30,tt;

void init()
{
 sda=1;
 somenop();
 scl=1;
 somenop();
  
}

void star()
{
 sda=1;
 somenop();
 scl=1;
 somenop();
 sda=0;
 somenop();
}
void stop()
{
 sda=0;
 somenop();
 scl=1;
 somenop();
 sda=1;
 somenop();
}
void ack()
{
 scl=1;
 somenop();
 
 scl=0;
 somenop();
}
void write_byte(uchar date)
{
 uchar i,temp;
 temp=date;
 for(i=0;i<8;i++)
 {
        scl=0;
  somenop();
  
        if((temp&0x80)==0x80)
        { sda=1;}
  else
  { sda=0;}
  temp=temp<<1;
  somenop();
  scl=1;
  somenop();
  scl=0;
  somenop();
 }
 scl=0;
 somenop();
 sda=1;
 somenop();
}
uchar read_byte()
{
 uchar i,temp1,j;
 scl=0;
 somenop();
 sda=1;
 somenop();
 for(i=0;i<8;i++)
 {
  scl=1;
  somenop();
  j=sda;
  temp1=(temp1<<1)|j;
  scl=0;
  somenop();
 }
   return temp1;
}


void write_address(uchar address,uchar date)
{
 star();
 write_byte(0xa0);
 ack();
 write_byte(address);
 ack();
 write_byte(date);
 ack();
 stop();
}
uchar read_address(uchar address)
{    
    uchar redata;
 star();
 write_byte(0xa0);
 ack();
 write_byte(address);
 ack();
 star();
 write_byte(0xa1);
 ack();
 redata=read_byte();
 stop();
 return redata;
}


void timer0() interrupt 1
{
 TH0=(65536-50000)/256;
 TL0=(65536-50000)%256;
 tt++;
    if(tt==20)
 {
        tt=0;
  sec++;
  if(sec==60)
         {sec=0;min++;
          
          if(min==60)
          { min=0;}
           write_address(100,min); delaym();
         }
        write_address(10,sec); delaym();  //把秒写入AT24C02的10地址
                                         //单片机写数据会占用一些时间，所以延时一会儿较好
        
 }
}

void int0(void) interrupt 0
{
 EA=0;
 min++;
 if(min==60)
 {
  min=0;
 }
 write_address(100,min);    //把分写入AT24C02的100地址
 delaym();
  EA=1;
}


void disp()
{
 P0=shum[sec%10];//sec 个位
 P2=0x08;
 delaym();

 P0=shum[sec/10];//sec 十位
 P2=0x04;
 delaym();

 P0=shum[min%10]&0x7f;   //加小数点
 P2=0x02;
 delaym();

 P0=shum[min/10];
 P2=0x01;
 delaym();
}

void main()
{
    TMOD=0x01;
 ET0=1;
    EX0=1;
    IT0=1;
    EA=1;
 TH0=(65536-50000)/256;
 TL0=(65536-50000)%256;
    TR0=1;
     init();
        sec=read_address(10);     ／／从ＡＴ２４Ｃ０２的１０地址读出秒数据
        min=read_address(100);／／从ＡＴ２４Ｃ０２的１００地址读出分数据

        while(1)
        {
          disp();
        }
}