Single-chip microcomputer: C language Implementation stopwatch count (start, end, reset button)

The stopwatch counting function is implemented using timers and external interrupts. The number 8th button represents the start/end of the timer, the C key represents a reset of 0, and is limited to 15 seconds for demonstration purposes.

There is a detailed comment in the code:

#include <reg52.h>sbit wei=p2^7;sbit duan=p2^6;sbit l1=p3^4;unsigned char code dofly_duanma[11]={0x3f,0x06,0x5b , 0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x40};//displays the segment code value 0~9unsigned char code DOFLY_WEIMA[]={0XFE,0XFD,0XFB,0XF7,0XEF,  0xdf,0xbf,0x7f};//corresponding to the corresponding digital tube lit, the accession code void delay (int t) {while (t--);}     The first parameter I represents the control of the first few digital tubes, n represents the number to be displayed in void screen (int i,int n) {p0=0; Duan=1;          duan=0;     P0=dofly_weima[i]; Wei=1;         wei=0;      P0=dofly_duanma[n];       Duan=1; duan=0;}    int Sec;int num;int i;int flag;int Main () {flag=1;    i=0;  num=0;sec=0;  wei=0;   duan=0;          Open interrupt ex0=1;           It0=1;          Ex1=1;               It1=1;           Timer initialization tmod |= 0x01;               Ea=1;              Et0=1;      Tr0=1;    l1=0; while (1) {if (num>=10) screen (3,NUM/10);     Screen (4,NUM%10);     Delay (10); Screen (5,10);     Screen (6,SEC/10);         Screen (7,sec%10);} return 0;}   void Timer_0 () Interrupt 1 using 1{th0= (65536-10000)/256; TL0= (65535-10000)%256;    if (flag==1) {i++;     Sec++;if (sec==100)//0.1mssec=0;    if (i==101)//1s {i=0;    num++;     if (num==15) num=0; }}}void ACTION1 () interrupt 0 {Flag=!flag;}    void ACTION2 () Interrupt 2 {if (flag==0) {screen (7,0);  num=0;sec=0; }}

Single-chip microcomputer: C language Implementation stopwatch count (start, end, reset button)