5.c

键盘测试的源文件 是一个简单的C语言程序,在KEIL C中已经成功仿真了

#include "reg51.h"
#define uchar unsigned char
#define uint unsigned int
void d1ms(void);
uchar kbscan(void); 

void main(void)
{
uchar key;
while(1)
{
key=kbscan();

d1ms();
//ACC=key;
}
}

void d1ms(void)
{
uchar i;
for(i=200;i>0;i--) {}
}

uchar kbscan(void)
{
uchar sccode,recode;
P1=0xf0;
if((P1&0xf0)!=0xf0)
{
  d1ms();
  if((P1&0xf0)!=0xf0)
   {
    sccode=0xfe;
    while((sccode&0x10)!=0)
    {
     P1=sccode;
     if((P1&0xf0)!=0xf0)
      {
       recode=(P1&0xf0)|0x0f;
       return((~sccode)+(~recode));
      }
     else sccode=(sccode<<1)|0x01;
    }
   }
  }
return(0);
}