关于单片机C编程的菜鸟问题.

#include"main.h"
unsigned char getbutton(void){
int i=0;
unsigned char j=1;
unsigned char k=0;
unsigned char l=0;
while(j){
keyboard=0;
while(j){
k=keyboard&0xfc;
if(k==0)
j=1;
else
j=0;
}
while(i++<2000);
keyboard=0;
k=keyboard&0xfc;
if(k==0)
j=1;
else j=0;
}
j=1;
keyboard=0;
while(j){
l=keyboard&0xfc;
if(l==0)
j=0;
else
j=1;
}
switch(k){
case 0x04:return(1);
case 0x08:return(2);
case 0x10:return(3);
case 0x20:return(4);
case 0x40:return(5);
case 0x80:return(6);
default:;
}
}

这个有没问题啊?请高手指点..

相关了解……