//按下

#include <reg52.h>
sbit ADDR0=P1^0;
sbit ADDR1=P1^1;
sbit ADDR2=P1^2;
sbit ADDR3=P1^3;
sbit ENLED=P1^4;
sbit KEY1=P2^4;
sbit KEY2=P2^5;
sbit KEY3=P2^6;
sbit KEY4=P2^7;

unsigned char LedChar[]={//数码管
   0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,
   0x80,0x90
};
void delay()//延时
{
   unsigned int i=1000;
    while(i--);
}
void main()
{
 bit keybuf=1;//按键值暂存
 bit backup=1;//键值备份
 unsigned char cnt=0;//按键计数
 ENLED=0;
 ADDR3=1;
 ADDR2=0;
 ADDR1=0;
 ADDR0=0;
 P2=0xF7;
 P0=LedChar[cnt];//初始显示0

while(1)//按下时执行一次循环，弹起在执行一次循环
 {
    keybuf=KEY4; 把当前值扫描暂存
    if(keybuf !=backup) //当前值与前一次值不同说明按键有动作
    {
       delay();
    if(keybuf==KEY4) //判断按键值发没发生改变。防止抖动
    {
    if(backup==1)//如果前次值位1，说明当前动作是按下
   {
           cnt++;//按键次数加1
     if(cnt>=10)
     {
        cnt=0;
     }
     P0=LedChar[cnt];
   }
    }
    backup=keybuf;   //更新备份，下一次作比较
    }
 }
}

//弹起

#include <reg52.h>
sbit ADDR0=P1^0;
sbit ADDR1=P1^1;
sbit ADDR2=P1^2;
sbit ADDR3=P1^3;
sbit ENLED=P1^4;
sbit KEY1=P2^4;
sbit KEY2=P2^5;
sbit KEY3=P2^6;
sbit KEY4=P2^7;

unsigned char LedChar[]={
   0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,
   0x80,0x90
};
void delay()
{
   unsigned int i=1000;
    while(i--);
}
void main()
{
    bit keybuf=1;
 bit backup=1;
 unsigned char cnt=0;
 ENLED=0;
 ADDR3=1;
 ADDR2=0;
 ADDR1=0;
 ADDR0=0;
 P2=0xF7;
 P0=LedChar[cnt];

while(1)
 {
    keybuf=KEY4;
    if(keybuf !=backup) 
    {
       delay();
    if(keybuf==KEY4)
    {
      if(backup==0)//只是这里改为0
   {
           cnt++;
     if(cnt>=10)
     {
        cnt=0;
     }
     P0=LedChar[cnt];
   }
    }
    backup=keybuf;  
    }
 }
}