//程序功能：按下按键S1~S20数码管显示相应的键值
#include "reg52.h"
#define uchar unsigned char
#define uint unsigned int
uchar code disptab[]={0x3f,0x6,0x5b,0x4f,0x66,
0x6d,0x7d,0x27,0x7f,0x6f,0x77,0x7c,0x39,0x5e,
0x79,0x71,0x0};
uchar code dispbit[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf};
uchar dispbuf[6];
uchar code th0=(65536-2536)/256;
uchar code tl0=(65536-2536)%256;
sbit we=P2^7;
sbit du=P2^6;
void dlms(uchar x)
{ uchar y;
for(;x>0;x--)
for(y=200;y>0;y--);
}
uchar keyscan()
{
uchar sccode;
uchar recode;
P3=0xf0;
if((P3&0xf0)!=0xf0)
{
dlms(2);
if((P3&0xf0)!=0xf0)
{
sccode=0xfe;
while((sccode&0x10)!=0)
{
P3=sccode;
if((P3&0xf0)!=0xf0)
{
recode=(P3&0xf0)|0x0f;
return(~recode+~sccode);
}
else
{
sccode=(sccode<<1)|0x01;
}
}
}
}
return(0);
}
void Init_timer0()
{
TMOD=0x01;
TH0=th0;
TL0=tl0;
EA=1;
ET0=1;
TR0=1;
}
void timer0() interrupt 1
{ static uchar count;
uchar tmp;
P0|=0x3f;
we=1;
tmp=dispbit[count];
P0=tmp;
we=0;
du=1;
tmp=dispbuf[count];
tmp=disptab[tmp];
P0=tmp;
du=0;
count++;
if(count==6)
{
count=0;
}
TH0=th0;
TL0=tl0;
}
void main()
{ uchar key;
Init_timer0();
P1=0xff;
dispbuf[5]=16;
dispbuf[4]=16;
dispbuf[3]=16;
dispbuf[2]=16;//关闭其余位
while(1)
{
key=keyscan();
if(key)
{
dispbuf[1]=key/16;
dispbuf[0]=key%16;
}
}
}
