24秒倒计时器系统设计
一、仿真图
（一）Proteus元器件查找
1、芯片：89C51
2、电阻：res
3、缓冲器74HC244
4、数码管7SEG-------CC共阴极
5、非门74LS04
6、按键button
二、程序
#include
unsigned char code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f}; typedef unsigned int uint;
uint i,j,f1=0;
uint q=4,p=2;
uint sum = 0;
sbit P2_0=P2^0;
sbit P2_1=P2^1;
sbit P2_2=P2^2;
sbit P2_3=P2^3;
uint num2=0,num=24,shi=2,ge=4;
void T1_time()interrupt 3
{
TH1=(65536-49000)/256;
TL1=(65536-49000)%256;
num2++;
if(num2==20){
num2=0;
if(!f1){
if(num!=0)num--;
shi=num/10;
ge=num%10;
}
}
}
void ex_int()interrupt 0
{
num=24;
}
void ex_int1()interrupt 2
{
sum++;
if(sum%2==1)
f1=1;
else
f1=0;
}
void delay()
{
uint j;
for(j=0;j<200;j++);
}
void disply()
{
P2&=0XF0;
P1=table[shi];
P2_0=1;
delay();
P2&=0XF0;
P1=table[ge];
P2_1=1;
delay();
P1=0;
P2&=0XF0;
}
main()
{
TMOD=0X10;
TH1=(65536-49000)/256;
TL1=(65536-49000)%256;
EA=1;
EX0=1;
IT0=1;
EX1=1;
IT1=1;
ET1=1;
TR1=1;
while(1)
{
disply();
}
}