單片機10秒計時程序錯誤

ID:884109 · 發表于 2021-5-31 18:20

單片機實現秒表計時程序，按一次按鍵，開始計時，第二次按下暫停，再按則清零。
但是不知為什么，第二次按鍵時，顯示全是0.
#include <reg51.h>
#include <intrins.h>

#define uint unsigned int
#define uchar unsigned char

//共陰數碼管段選表0~9和-
uchar  code tabeld[]= {0xBF, 0x86, 0xDB, 0xCF, 0xE6, 0xED, 0xFD, 0x87, 0xFF, 0xEF,0x40};
uchar  code tabel[]= {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F,0x40};
uchar  code wei[]= {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};

//uchar hour,minute,second,i;
uchar times=0,second,keyNum=0;
sbit key = P2^7;

void delay();
void display();
void timerInit();

void main(void)
{
      timerInit();

      second = 0;
      key = 1;


      while(1){
            display();
            if(       !key){
                     keyNum++;
                     switch(keyNum){
                              case 1:
                                    TH0 = 0xED;
                                    TL0 = 0xFF;
                                    TR0 = 1;
                                    break;
                              case 2:
                                    TR0  = 0;
                                    display();
                                    break;
                              case 3:
                                    second = 0;
                                    keyNum = 0;
                                    display();
                     }
                     while(       key & 1 == 0);
            }
      }
}

void timerInit()
{
      TMOD = 0x01;
      TH0 = 0xED;
      TL0 = 0xFF;

      EA = 1;
      ET0 = 1;
}

void delay()
{
      uchar i;
      for( i = 0; i < 111; i++ ) ;
}

void display()
{
      P0 = P1 = 0;
      delay();
      P0 = tabeld[second/10];
      P1 = wei[ 1 ];
      delay();
      P0 = P1 = 0;
      delay();
      P0 =  tabel[second%10];
      P1 = wei[ 0 ];
      delay();
}

void timer0Int() interrupt 1
{
      TH0 = 0xED;
      TL0 = 0xFF;
      TR0 = 0;
      times++;
      if( 20 == times){
               times = 0;
            second++;
            display();
      }
      if(second == 99){
               TR0 = 0;
            second = 0;
            keyNum = 2;
      } else{
               TR0 = 1;
      }
}