Dynamic display of digital tube stopwatch of single chip microcomputer

Based on MCU STC89C52RC, Use timer 1, Adopt the method of dynamic scanning , The stopwatch is displayed in the first three digits of the nixie tube , Accurate to 0.01 second , such as 5.03 second , Cycle all the time .

First, set the display refresh rate to 6ms, Every time 2ms Refresh 1 A digital tube , Every time 10ms Calculate the time .

Time displayed 3 Bits are structured .

The first is the circuit structure , Adopt common cathode digital tube ,74573 Latch and 138 Decoder .

Then there is the program code

/*********************************
@title:Óö¨Ê±Æ÷1ºÍ¶¯Ì¬É¨Ãè·½·¨£¬ÔÚÊýÂë¹ÜµÄÇ°Èýλ
                ÏÔʾ³öÃë±í£¬¾«È·µ½1%Ã룬¼´ºóÁ½Î»ÏÔʾ1%Ã룬
                Ò»Ö±Ñ­»·
@MCU:STC89C52
@name: Wang Yongxing
@date: 2014.08.18
**********************************/

# include "MacroAndConst.h"
# include <stc89c5xrc.h>
# include <intrins.h>


sbit LE_74573 = P1^0;
sbit LSA_74LS138 = P2^2;
sbit LSB_74LS138 = P2^3;
sbit LSC_74LS138 = P2^4;


//¹²ÒõÊýÂë¹Ü0-F dp-a£º0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
//0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71
char SegLed[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
                                0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};

void InitTimer1(void);
void SegLedDisplay(void);

struct
{
    char sec0;//Ãë±í×î¸ßλ
    char sec1;//Ãë±íСÊýµãºóµÚһλ
    char sec2;//Ãë±íСÊýµãºóµÚ¶þλ
}sec;

uchar num = 7;
char ms10flag = 0;


int main(void)
{
    
    
    InitTimer1();//¶¨Ê±Æ÷0³õʼ»¯
    EA = 1;//ʹÄÜϵͳ×ÜÖжÏ
    LE_74573 = 1;
    sec.sec0 = 0;
    sec.sec1 = 0;
    sec.sec2 = 0;
    while(1)
    {}    
    return 0;
}

void InitTimer1(void)
{
    TMOD = 0x10;//¶¨Ê±Æ÷0£¬16λ¶¨Ê±Æ÷
    TH1 = 0xF8;//¶¨Ê±Îª2ms£¬50*1000us
    TL1 = 0x2F;
    ET1 = 1;    //ʹÄܶ¨Ê±Æ÷0µÄÖжÏ
    TR1 = 1;//¶¨Ê±Æ÷0¿ªÊ¼ÔËÐÐ
}

void Timer1Isr() interrupt 3 using 1
{
    TH1 = 0xF8;//¶¨Ê±Îª2ms£¬50*1000us
    TL1 = 0x2F;
    ms10flag++;
    if(ms10flag == 5)
    {
        ms10flag = 0;
        P0 = 0X00;//Çå³ýÏÔʾ
            if(++sec.sec2 == 10)//¼ÆËãʱ¼ä
            {
                sec.sec2 = 0;
                if(++sec.sec1 == 10)
                {
                    sec.sec1 = 0;
                    if(++sec.sec0 == 10)
                    {
                        sec.sec0 = 0;
                    }
                }
            }        
    }    
    SegLedDisplay();
}    


void SegLedDisplay(void)
{

    
        switch(num)
        {
    //        case 0:LSC_74LS138 = 0;LSB_74LS138 = 0;LSA_74LS138 = 0;break;
    //        case 1:LSC_74LS138 = 0;LSB_74LS138 = 0;LSA_74LS138 = 1;break;
    //        case 2:LSC_74LS138 = 0;LSB_74LS138 = 1;LSA_74LS138 = 0;break;
    //        case 3:LSC_74LS138 = 0;LSB_74LS138 = 1;LSA_74LS138 = 1;break;
    //        case 4:LSC_74LS138 = 1;LSB_74LS138 = 0;LSA_74LS138 = 0;break;
            case 5:
            {
                LSC_74LS138 = 1;
                LSB_74LS138 = 0;
                LSA_74LS138 = 1;
                P0 = SegLed[sec.sec2];
                break;
            }
            case 6:
            {
                LSC_74LS138 = 1;
                LSB_74LS138 = 1;
                LSA_74LS138 = 0;
                P0 = SegLed[sec.sec1];
                break;
            }
            case 7:
            {
                LSC_74LS138 = 1;
                LSB_74LS138 = 1;
                LSA_74LS138 = 1;    
                P0 = SegLed[sec.sec0];
                P0 |= 0x80;//ÏÔʾСÊýµã
                break;
            }
        }    
        if(--num == 4)
        {
            num = 7;
        }
}

I don't know what happened ,keil The Chinese comments of the code are all garbled .

There is a problem in the middle , To show the decimal point , The topmost display uses the statement

P0 = 0x80|SegLed[sec.sec0];

Digital tube with the highest display of seconds , stay 0,6,9 The display is abnormal , Full flash

Later, the sentence was changed to

                P0 = SegLed[sec.sec0];
                P0 |= 0x80;//ÏÔʾСÊýµã

Fangzhengchang , But I still don't know why . But the effect is very good .