1.功能

倒计时器的设计与制作

2.程序

#include <REGX51.H>

#define uchar unsigned char

#define uint unsigned int

uchar counter=0;

uchar i=9;

uchar code SEG[16]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e};

void timer0(void) interrupt 1 using 0

{

TH0=-50000/256;

TL0=-50000%256;

counter++;

if(counter ==40)

{

counter=0;

if(i==16)

i=0;

else

i++;

P0=SEG[i];

}

}

void main(void)

{

P0=SEG[0];

P2=0xef;

TMOD=0X01;

TH0=-50000/256;

TL0=-50000%256;

EA=1;

ET0=1;

TR0=1;

while(1)

{;}

}

3.小结

´本电路实现了0-16正计时，每2s进一位，逢16归0，数码管上第123位显示。