程序如下：

#include<reg52.h>

#define uchar unsigned char

#define uint unsigned int

void delayMS(unsigned int z);

uchar keyscan(void);

void main(void)

{

uchar key;

while(1)

{

key=keyscan();

delayMS(50);

}

}

void delayMS(unsigned int z)

{

unsigned i,j;

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

for(j=122;j>0;j--);

}

uchar keyscan(void)

{

uchar scode,scode1,scode2,k;

P1=0xf0;

scode1=P1&0xf0;

if(scode1!=0xf0)

{

delayMS(10);

scode1=P1&0xf0;

if(scode1!=0xf0)

{

scode1=P1^0xf0; //行号

P1=0x0f;

scode2=P1^0x0f; //列号

scode=scode1+scode2;

switch(scode)

{

case 0x11: k=1;break;

case 0x12: k=2;break;

case 0x14: k=3;break;

case 0x18: k=4;break;

case 0x21: k=5;break;

case 0x22: k=6;break;

case 0x24: k=7;break;

case 0x28: k=8;break;

case 0x41: k=9;break;

case 0x42: k=10;break;

case 0x44: k=11;break;

case 0x48: k=12;break;

case 0x81: k=13;break;

case 0x82: k=14;break;

case 0x84: k=15;break;

case 0x88: k=16;break;

default: k=0;break;

}

}

}

return k;

}