<code class="lang-cpp">#include <reg51.h> 
#define uchar unsigned char 
#define uint unsigned int
  
/*
变量定义
*/
uchar key_stime_counter,hight_votage=15,timeT_counter; 
bit key_stime_ok;
  
/*
引脚定义
*/
sbit control_signal=P0^0; 
sbit turn_left=P3^4;
sbit turn_right=P3^5;
  
/*****************************************************************
名称：定时器0初始化
功能：20ms定时,11.0592M晶振
初值=65536-11059200*0.02/12=65536-18432=47104=0xB800   20ms
初值=65536-11059200*0.0001/12=65536-92.16=64430=0xFFA3 0.1ms
*****************************************************************/
void TimerInit()
{     
    control_signal=0;
    TMOD=0x01;                               //设置定时器0为工作方式1
    EA=1;                                   //开总中断
    ET0=1;                                   //定时器0中断允许
    TH0 = 0xFF;                        //定时器装初值
    TL0 = 0xA3;
    TR0=1;          //启动定时器0                                
}
  
/**********************************************
定时器0中断服务函数
***********************************************/
void timer0(void) interrupt 1 using 0 
{
    TH0=0xFF;
    TL0=0xA3; //定时器0重新装入数值
  
if (++key_stime_counter>=200)
{
    key_stime_counter=0;
    control_signal=1;
    key_stime_ok = 1;               // 20ms到 
    timeT_counter=0;
}
  
if (key_stime_ok&&(++timeT_counter>=hight_votage))
{
    key_stime_ok=0;
    timeT_counter=0;
    control_signal=0;              // hight_votage*0.1ms到 
}
}
  
/*********************************************
名称：键盘扫描
功能：在按键稳定期内判断键值，并返回键值
**********************************************/
uchar keyscan(void)
{
    static char key_state = 0;
    static char key_value = 0;
    uchar key_press, key_return = 0;
    key_press = turn_left & turn_right;     //读按键I/O电平
               
    switch (key_state) 
    {
        case 0 :     // 按键初始态
            if (key_press==0) key_state = 1; // 键被按下，但需要确认是否是干扰
            break;
        case 1 :     // 按键确认态
            if (key_press==0)//如有键按下则不是干扰，判断键值
            {                   
                if(turn_left==0)               //判断是哪一个按键被按下
                {
                    key_value=1;       //按键较多时可采用switch选择结构
                } 
                else if(turn_right==0)
                {
                    key_value=2;
               }
                else
                {
                   key_value=0;
                    key_state = 2; // 状态转换到键释放态
                }
            }
            else
            {
                key_state = 0; // 按键已抬起，属于干扰，转换到按键初始态
            }
            break;
        case 2 :
            if (key_press==1) 
            {
                key_return=key_value;//按键释放后再输出键值,如果按下键就输出则可省略key_value
                key_value=0;
                key_state = 0; //如果按键释放，转换到按键初始态
            }
            break;
    }
    return key_return; //返回键值
}
  
/*********************************************
名称：按键处理
功能：
**********************************************/
void key_operation(void)
{    
    switch (keyscan())      //根据键值不同，执行不同的内容
    {
        case 1:
            hight_votage -= 1;
            if(hight_votage < 5)
            {
                hight_votage = 5;
            }
            break;
        case 2:
            hight_votage += 1;
            if(hight_votage > 25)
            {
                hight_votage = 25;
            }
            break;
        default :
            break;
    } 
}
  
  
//LED显示函数
void diplay()
{
    if(hight_votage>=5&&hight_votage<=7) p1="0xFD;  " 1灯亮，舵机接近或到达右转极限位置     if(hight_votage>7&&hight_votage<=10) p1="0xFB;  " 2灯亮     if(hight_votage>10&&hight_votage<=13) p1="0xF7;  //3灯亮"     if(hight_votage>13&&hight_votage<=16) p1="0xEF;  //4灯亮，舵机到达中间位置"     if(hight_votage>16&&hight_votage<=19) p1="0xDF;  //5灯亮"     if(hight_votage>19&&hight_votage<=22) p1="0xBF;  //6灯亮"     if(hight_votage>22&&hight_votage<=25) p1="0x7F;  //7灯亮，舵机接近或到达左转极限位置" }    *主程序* void main(void) {     timerinit();     while(1)     {         key_operation();         diplay();     } }< code></=25)></=22)></=19)></=16)></=13)></=10)></=7)></reg51.h></code>