key.c

里面有c和单片机的程序

# include<reg52.h>
# include<stdio.h>

unsigned char state;

void key()
{
unsigned char key;
key=(P2&&0X0F);
delay();
switch(key)
{case 0X0E: state=1;
            break;
 case 0X0D: state=2;
            break;
 case 0X0B: state=3;
            break;
 case 0X07: state=4;
            break;
 default:   state=0;
 }
}