求助大神STC89C52单片机，用数码管显示时间，请看程序

ID:87568 · 发表于 2015-8-27 15:55

STC89C52单片机，用数码管显示时间，请看程序：
#include<reg52.h>
#define uint unsigned int
#define uchar unsigned char
uchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
uchar num,a,a1,b,b1,c,c1;
uchar shi,fen,miao;
sbit fm=P3^4;

void delay(uchar time)
{
  uchar i,j;
  for(i=time;i>0;i--)
for(j=110;j>0;j--);
}

void init()
{
  TMOD=0x01;
  TH0=(65536-45872)/256;
  TL0=(65536-45872)%256;
  EA=1;
  ET0=1;
  TR0=1;
}

void display(char a,a1,b,b1,c,c1)
{
  P1=0x00;
  P2=table[a];
  delay(5);
  P1=0x01;
  P2=table[a1];
  delay(5);
  P1=0x02;
  P2=0x40;
  delay(5);

  P1=0x03;
  P2=table;
  delay(5);
  P1=0x04;
  P2=table[b1];
  delay(5);
  P1=0x05;
  P2=0x40;
  delay(5);

  P1=0x06;
  P2=table[c];
  delay(5);
  P1=0x07;
  P2=table[c1];
  delay(5);
}

void t0_time() interrupt 1
{
  TH0=(65536-45872)/256;
  TL0=(65536-45872)%256;
  num++;
}

void main()
{
  init();
  shi=15;
  fen=31;
  miao=00;
  while(1)
  {
if(num==20)
{
   num=0;
   if(miao==59) //问题一：为什么miao==59而不等于60
   {
      miao=-1;    //问题二：为什么不是miao=0
      if(fen==59)
      {
   fen=-1;
      if(shi==24)
            shi=-1;
   shi++;
   }
   fen++;
   if(fen==50){fm=0;delay(80);fm=1;}
   }
   miao++;
   }
a=shi/10;
a1=shi%10;
b=fen/10;
b1=fen%10;
c=miao/10;
c1=miao%10;
display(a,a1,b,b1,c,c1);
  }
}