timer.c

一个用C51编写的倒计时程序

//------------------------------
//设置当前值：FE A0 02 MM NN  （BCD码）
//要当前值：  FE A1 01 00 回传值 FE A1 02 MM NN   BCD码）
//------------------------------
#include<At89x52.h>
#include<initled.h>
//------------------------------------------
#define condition_1 time_min==0&&time_sec==0
#define condition_2 time_min==0&&time_sec!=0
#define condition_3 time_min!=0&&time_sec==0
#define condition_4 time_min!=0&&time_sec!=0
#define so_pclength    p_pc_head-so_pc_buf
//------------------------------------------
sbit d_clk=P3^7;		
sbit d_dat=P3^6;		
sbit d_st=P3^5;			

bit bit_timech=0;

unsigned char d[5];
unsigned char so_pc_buf[10];
unsigned char time60,time_min=99,time_sec=59,*p_pc_head=so_pc_buf;
//////////////////////
void out_disp(unsigned char *p) 
{unsigned char i,j;	
	for(i=0;i<5;i++,p++) 
       {for (j=0;j<8;j++) 
           {if (*p&1) d_dat=1;else d_dat=0;
		       d_clk=1;*p>>=1;d_clk=0;
		   }
	   }
d_st=1;
for(i=0;i<10;i++);
d_st=0;
}
//------------------------------------
//d0min/ d1min% d2- d3sec/ d4sec%
//------------------------------------
void calculattime(void )
{    if(condition_1);
else if(condition_2)time_sec-=1;
else if(condition_3){time_sec=59;time_min-=1;}
else if(condition_4)time_sec-=1;
  else {time_sec=88;time_min=88;}

d[0]=un_disp[time_min/10];d[1]=un_disp[time_min%10];
d[2]=l_;
d[3]=un_disp[time_sec/10];d[4]=un_disp[time_sec%10];
out_disp(d);
}
////////////////////
void int_t0(void) interrupt 1 using 1
{	TL0=0xa0;TH0=0x42;	
	if ((++time60)>=19) {time60=0;bit_timech=1;}	
}
////////////////////
void int_pc(void) interrupt 4 using 2
{	 if(RI) {RI=0;
             if((SBUF==0xfe)||(so_pclength>=8))p_pc_head=so_pc_buf;
             *p_pc_head++=SBUF;
            }
}
//------------------
void pc_comand(void )
{unsigned char datebuf;
if((so_pclength)>=4)//while
       {if(so_pclength>=(so_pc_buf[2]+3))
	       {switch(so_pc_buf[1]){
              case 0xa0:if(so_pc_buf[3]<=0x99&&so_pc_buf[4]<=0x99)
			               {datebuf=so_pc_buf[3];
			            	time_min=(datebuf>>4)*10+(so_pc_buf[3]&=0x0f);
					 		datebuf=so_pc_buf[4];
			         		time_sec=(datebuf>>4)*10+(so_pc_buf[4]&=0x0f);}					 
					 	break;
              case 0xa1:SBUF=0xfe;
                        while(TI==0);TI=0;SBUF=0xa1;
				    	while(TI==0);TI=0;SBUF=0x02;
						while(TI==0);TI=0;SBUF=((datebuf=time_min/10)<<4)|(time_min%10);
						while(TI==0);TI=0;SBUF=((datebuf=time_sec/10)<<4)|(time_sec%10);
						while(TI==0);TI=0;
						break;
                default:break;}
            p_pc_head=so_pc_buf;
   	      }
       }
//return(0);
}
////////////////////
void watchdog(void )
{unsigned char i;
d_clk=1;
for(i=0;i<10;i++);
d_clk=0;
}
////////////////////
void main(void) 
{	TMOD=0x21;
	SCON=0x50;
    TH1=TL1=0xE8; //1200
    TH0=0x42;// ;50MS
	TL0=0xA0;
    TR1=TR0=ET0=ES=1;
    ET1=0;
	EA=1;
    d_clk=d_dat=d_st=0;
         
	while (1) 
	{if(bit_timech){bit_timech=0;calculattime();}
	watchdog();
    pc_comand();
	}
}
//////////////////////