矩阵键盘中断扫描

#include

#define uchar unsigned char

#define KeyPort P1

bit keyflag;

uchar code tab[16]={0xc0,0xf9,0xa4,0xb0,0x99,

0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e}; void p_INT0(void) interrupt 0 //外部中断0中断处理函数{

keyflag=1;

}

void delay(uchar i)

{

uchar j,k;

for(j=50;j>0;j--)

for(k=i;k>0;k--);

}

uchar keyscan(void) //按键扫描子函数

{

unsigned char Val;

KeyPort=0xf0;//高四位置高，低四位拉低

if(KeyPort!=0xf0)//表示有按键按下

{

delay(40); //去抖

if(KeyPort!=0xf0)

{ //表示有按键按下

KeyPort=0xfe; //检测第一行

if(KeyPort!=0xfe)

{

Val=KeyPort&0xf0;

Val+=0x0e;

while(KeyPort!=0xfe);

delay(40); //去抖

while(KeyPort!=0xfe);

return Val;

}

KeyPort=0xfd; //检测第二行

if(KeyPort!=0xfd)

{

Val=KeyPort&0xf0;

Val+=0x0d;

while(KeyPort!=0xfd);

delay(40); //去抖

while(KeyPort!=0xfd);

return Val;

}

KeyPort=0xfb; //检测第三行

if(KeyPort!=0xfb)

{

Val=KeyPort&0xf0;

Val+=0x0b;

while(KeyPort!=0xfb);

delay(40); //去抖

while(KeyPort!=0xfb);

return Val;

}

KeyPort=0xf7; //检测第四行

if(KeyPort!=0xf7)

{

Val=KeyPort&0xf0;

Val+=0x07;

while(KeyPort!=0xf7);

delay(40);//去抖

while(KeyPort!=0xf7);

return Val;

}

}

}

return 0xff;

}

uchar KeyPro(void) //按键处理子函数{

switch(keyscan())

{

case 0x7e:return 0;break;

case 0xbe:return 1;break;

case 0xde:return 2;break;

case 0xee:return 3;break;

case 0x7d:return 4;break;

case 0xbd:return 5;break;

case 0xdd:return 6;break;

case 0xed:return 7;break;

case 0x7b:return 8;break;

case 0xbb:return 9;break;

case 0xdb:return 10;break;

case 0xeb:return 11;break;

case 0x77:return 12;break;

case 0xb7:return 13;break;

case 0xd7:return 14;break;

case 0xe7:return 15;break; default:return 0xff;break;

}

}

void main (void)

{

uchar num;

EA=1;

EX0=1;

IT0=1;

while(1)

{

KeyPort=0xf0; // 赋值用于中断检测if(keyflag==1)

{

keyflag=0;

num=KeyPro();

if(num!=0xff)

P0=tab[num];

}

}

}