2.独立按键

include <REGX52.H>

include "delay.h"

unsigned char i;
void main(){
while(1){

if(P3_11){
delay(0.02);
while(P3_11);
delay(0.02);

P2=~(0X00+i);
i++;

}}
}

include <REGX52.H>

include "delay.h"

unsigned char key(){//??????
unsigned char keynum=0;
if(P3_10){delay(0.02);while(P3_00);delay(0.02);keynum=1;}
if(P3_00){delay(0.02);while(P3_10);delay(0.02);keynum=2;}
if(P3_20){delay(0.02);while(P3_20);delay(0.02);keynum=3;}
if(P3_30){delay(0.02);while(P3_30);delay(0.02);keynum=4;}
return keynum;
}