单片机计时程序

sbit P3_5 =P3^5

unsigned char code dispcode[]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,

0x80,0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E,0x00}

unsigned char second

unsigned char keycnt

unsigned int tcnt

void main(void)

{

unsigned char i,j

TMOD=0x02

ET0=1

EA=1

second=0

P1=dispcode[second/10]

P2=dispcode[second%10]

while(1)

{

if(P3_5==0)

{

for(i=20i>0i--)

for(j=248j>0j--)

if(P3_5==0)

{

keycnt++

switch(keycnt)

{

case 1:

TH0=0x06

TL0=0x06

TR0=1

break

case 2:

TR0=0

break

case 3:

keycnt=0

second=0

P1=dispcode[second/10]

P2=dispcode[second%10]

break

}

while(P3_5==0)

}

}

}

}

void t0(void) interrupt 1 using 0

{

tcnt++

if(tcnt==4000)

{

tcnt=0

second++

if(second==100)

{

second=0

}

P1=dispcode[second/10]

P2=dispcode[second%10]

}

}

#include

#define

uint

unsigned

int

#define

uchar

unsigned

char

sbit

p27=P2^7//数码管位选端定义

uchar

c,i

//数码管译码表

unsigned

char

code

NumDecode[]

=

{

0XC0,//0

0XF9,//1

0XA4,//2

0XB0,//3

0X99,//4

0X92,//5

0X82,//6

0XF8,//7

0X80,//8

0X90,//9

}

void

main()

{

i=0//10秒计时设置

c=0//中断次数计数

p27=1//数码管位选端关闭

TMOD=1//设置定时器0为工作方式1

TH0=(65536-46080)/256//定时50ms高8位求模

TL0=(65536-46080)%256//定时50ms低8位求余

EA=1//开总中断

ET0=1//定时器0中断

TR0=1//启动定时器0

while(1)

{

if(c==20)//50ms中断20次

{

c=0

i++//倒计时总数每秒减1

}

if(i<10)

{

p27=0//数码管位选选通

P0=NumDecode[i]//显示数据

}

else

//循环计时设置

{

i=0

}

}

}

void

timer0()

interrupt

1//定时器0中断入口

{

TH0=(65536-46080)/256//定时器重新赋初值

TL0=(65536-46080)%256

c++//中断次数

}