用數碼管的前兩位顯示一個十進制數,,變化范圍為00~59,開始時顯示00,每按下S2鍵一次,數值加1;每按下S3鍵一次,數值減一;每按下S4鍵一次,數值歸零;按下S5鍵一次,利用定時器功能使數值開始自動每秒加1,再次按下S5鍵,數值停止自動加1,保持顯示原數。
#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit key1=P3^4;
sbit key2=P3^5;
sbit key3=P3^6;
sbit key4=P3^7;
sbit dula=P2^6;
sbit wela=P2^7;
uchar code table[]={
0x3f,0x06,0x5b,0x4f,
0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,
0x39,0x5e,0x79,0x7c};
void delayms(uint);
uchar num0,num;
void display(uint num)
{
uint shi,ge;
shi=num/10;
ge=num%10;
dula=1;
P0=table[shi];
dula=0;
P0=0xff;
wela=1;
P0=0xfe;
wela=0;
delayms(5);
dula=1;
P0=table[ge];
dula=0;
P0=0xff;
wela=1;
P0=0xfd;
wela=0;
delayms(5);
}
void delayms(uint xms)
{
uint i,j;
for(i=xms;i>0;i--)
for(j=110;j>0;j--);
}
void init()
{
TMOD=0x01;
TH0=(65536-45872)/256;
TL0=(65536-45872)%256;
EA=1;
ET0=1;
}
void keyscans()
{
if(key1==0)
{
delayms(10);
if(key1==0)
{
num++;
if(num==60)
num=0;
while(!key1);
}
}
if(key2==0)
{
delayms(10);
if(key2==0)
{
if(num==0)
num=60;
num--;
while(!key2);
}
}
if(key3==0)
{
delayms(10);
if(key3==0)
{
num=0;
while(!key3);
}
}
if(key4==0)
{
delayms(10);
if(key4==0)
{
while(!key4);
TR0=~TR0;
}
}
}
void main()
{
init();
while(1)
{
keyscans();
display(num);
}
}
void T0_time()interrupt 1
{
TH0=(65536-45872)/256;
TL0=(65536-45872)%256;
num0++;
if(num0==20)
{
num0=0;
num++;
if(num==60)
num=0;
}
}
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