单片机键盘扫描程序(4*4)

//—-键盘扫描程序——-
//—-用数码管显现相应的键值—–
//P1.0－－P1.3接行——-
//P1.4—P1.7接列——-
#include

unsigned char code table[ ]={0x3F,0x06,0x5B,0x4F,
0x66,0x6D,0x7D,0x07,
0x7F,0x6F,0x77,0x7C,
0x39,0x5E,0x79,0x71};//0到F的16个键植
unsigned char dis[4]={1,2,3,4};
unsigned int h=0;
unsigned long f=0;

void delayt(unsigned char t)//延时函数
{
unsigned char a;
while( –t != 0)
{
for(a=0;a<125;a++);
}
}

bit pkey(void)//判别键的否被按下，经过返回值确认
{
P1=0xf0;
if(P1!=0xf0)
{
delayt(20);
if(P1 != 0xf0)
return 1;
else
return 0;
}
else
return 0;
}
void getkey()
{
unsigned char key, j ,k, s;

if(pkey()== 1)//确认键被按下
{
P1=0xfe;
k=0xfe;
for(j=0;j<4;j++)
{
s=P1&0xf0;
switch(s)
{
case 0xe0: key=4*j+0; break;
case 0xd0: key=4*j+1; break;
case 0xb0: key=4*j+2; break;
case 0x70: key=4*j+3; break;
default: break;
}
k=(k<<1)|0x01;
P1=k;
}
}
if(key==11)
{
dis[0]=0;
dis[1]=0;
dis[2]=0;
dis[3]=0;
f=0;
}
else if(key==10)
{
f=1000*dis[3]+100*dis[2]+10*dis[1]+dis[0];
}
else if(key<10)
{
h=h+1;
if(h==1)
{
dis[0]=key;
}
else if(h==2)
{
dis[1]=dis[0];
dis[0]=key;
}
else if(h==3)
{
dis[2]=dis[1];
dis[1]=dis[0];
dis[0]=key;
}
else if(h==4)
{
dis[3]=dis[2];
dis[2]=dis[1];
dis[1]=dis[0];
dis[0]=key;
}
else if(h>4)
{
h=0;
dis[0]=0;
dis[1]=0;
dis[2]=0;
dis[3]=0;
}

}
}
void display()
{
P0=table[dis[0]];
P2=0x01;
delayt(100);

P0=table[dis[1]];
P2=0x02;
delayt(100);

P0=table[dis[2]];
P2=0x04;
delayt(100);

P0=table[dis[3]];
P2=0x08;
delayt(100);
}

void main(void)//主函数
{

while(1)
{
getkey();
display();

}
}