77、基于51单片机倒计时控制继电器电路图及程序

#include <reg52.h> #define uint unsigned int #define uchar unsigned char sbit beep=P1^4; sbit s1=P1^0; sbit s2=P1^1; sbit s3=P1^2; sbit jdq=P1^3; uint qian,bai,shi,ge,num,s1num; uchar code table[]= {/*0,1,2,3,4,5,6,7,8,9,*/ 0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90, }; uchar count; void delay(uint x) { uint a,b; for(a=x;a>0;a--) for(b=110;b>0;b--); } void display(qian,bai,shi,ge) { qian=num/1000; bai=num%1000/100; shi=num%100/10; ge=num%10; P0=table[qian]; P2=0xfe; delay(5); P0=table[bai]; P2=0xfd; delay(5); P0=table[shi]; P2=0xfb; delay(5); P0=table[ge]; P2=0xf7; delay(5); } void init() { EA=1; ET1=1; TR1=0; TMOD=0x10; TH1=(65536-45872)/256; TL1=(65536-45872)%256; num=99; } void keyscan() { if(s2==0) { delay(5); if(s2==0) { while(!s2); num+=1; if(num==9999) num=99; } } if(s3==0) { delay(5); if(s3==0) { while(!s3); num-=1; if(num==0) num=99; } } } void main() { init(); while(1) { keyscan(); display(qian,bai,shi,ge); if(s1==0) { delay(5); if(s1==0) { TR1=1; while(1) { display(qian,bai,shi,ge); jdq=0; if(num==-1) { jdq=1; beep=0; delay(5000); beep=1; beep=0; delay(5000); beep=1; beep=0; delay(5000); beep=1; while(1); } } } } } } void time1() interrupt 3 { TH1=(65536-45872)/256; TL1=(65536-45872)%256; count++; if(count==20) { count=0; num--; } }