#include<at89x51.h>
#include<intrins.h>
unsigned char code dispcode[]=
{0x3f,0x06,0x5b,0x4f,0x66, 
0x6d,0x7d,0x07,0x7f,0x6f}; 
unsigned char dispbuf[15]=
{2,0,0,8,1,2,3,0,0,0,0,0,0,0,1};//定義顯示緩存數組
sbit ds1302_data=P3^7;
sbit cs=P3^5;
sbit clk=P3^6;
unsigned char mscnt;
unsigned char dispbitcnt;
//短延時程序
void short_delay()
{
  unsigned char i;
  for(i=0;i<5;i++);
}
//長延時程序
void long_delay()
{
  unsigned char i;
  for(i=0;i<125;i++);
}
//向ds1302寫入一字節子程序
void ds1302_write(unsigned char ds1302_temp)
{
   unsigned char i,temp;
   long_delay();
   temp=ds1302_temp;
   for(i=0;i<8;i++)
     {
	   ds1302_data=temp&0x01;
	   short_delay();
	   clk=1;
	   short_delay();
	   clk=0;
	   temp=temp>>1;
	 }
}
//從ds1302讀取一字節子程序
unsigned char ds1302_read(void)
{
   unsigned char i,temp;
   long_delay();
   temp=0;
   for(i=0;i<8;i++)
     {
	    temp=temp>>1;
		if(ds1302_data)
		  {
		     temp=temp|0x80;
		  }
		clk=1;
		short_delay();
		clk=0;
		short_delay(); 
	 }
	return(temp);
}
//主程序
void main(void)
{
   unsigned char i;
   TMOD=0x02;
   TL0=0x06;
   TH0=0x06;
   TR0=1;
   ET0=1;
   EA=1;
   cs=0;
   while(1)
     {
	    clk=0;		
		short_delay();
		cs=1;
		ds1302_write(0x81);
		i=ds1302_read();
		cs=0;
		short_delay();
		clk=1;
		
		dispbuf[12]=(i>>4)&0x07;//秒
		dispbuf[13]=i&0x0f;
		
		clk=0;		
		short_delay();
		cs=1;
		ds1302_write(0x83);
		i=ds1302_read();
		cs=0;
		short_delay();
		clk=1;
		
		dispbuf[10]=(i>>4)&0x07;//分
		dispbuf[11]=i&0x0f;
		 
		clk=0;		
		short_delay();
		cs=1;
		ds1302_write(0x85);
		i=ds1302_read();
		cs=0;
		short_delay();
		clk=1;
			
		dispbuf[8]=(i>>4)&0x03;//小時
		dispbuf[9]=i&0x0f;

		clk=0;		
		short_delay();
		cs=1;
		ds1302_write(0x87);
		i=ds1302_read();
		cs=0;
		short_delay();
		clk=1;
		
		dispbuf[6]=(i>>4)&0x03;//日
		dispbuf[7]=i&0x0f;

		clk=0;		
		short_delay();
		cs=1;
		ds1302_write(0x89);
		i=ds1302_read();
		cs=0;
		short_delay();
		clk=1;
		
		dispbuf[4]=(i>>4)&0x01;//月
		dispbuf[5]=i&0x0f;

		clk=0;		
		short_delay();
		cs=1;
		ds1302_write(0x8d);
		i=ds1302_read();
		cs=0;
		short_delay();
		clk=1;
		
		dispbuf[2]=(i>>4)&0x0f;//年
		dispbuf[3]=i&0x0f;

		clk=0;		
		short_delay();
		cs=1;
		ds1302_write(0x8b);
		i=ds1302_read();
		cs=0;
		short_delay();
		clk=1;
		
		dispbuf[14]=((i&0x07)-1);//周
	
	 }
}
void t0(void)interrupt 1 using 0
{
   mscnt++;
   if(mscnt==8)//2ms數碼管掃描顯示
     {
	    mscnt=0;
		P2=dispbitcnt;
		P1=dispcode[dispbuf[dispbitcnt]];
		dispbitcnt++;
		if(dispbitcnt==15)
		  dispbitcnt=0;
	 }
}