PWM方波控制舵机

只看该作者 · 2023-5-14 19:51

#include <reg52.h>
sbit PWMOUT = P1^7;                   //方波输出通道
sbit KEY1 = P3^0;
sbit KEY2 = P3^1;
sbit KEY3 = P3^2;
unsigned char HighRH = 0;                //高电平重载值的高字节
unsigned char HighRL = 0;                //高电平重载值的低字节
unsigned char LowRH = 0;                   //低电平重载值的高字节
unsigned char LowRL = 0;                   //低电平重载值的低字节
unsigned char KeySta[4] = {                //按键的当前状态
1,1,1,1
};
void ConfigPWM(unsigned int fr, unsigned char dc);//启动PWM，fr是频率，dc为占空比
void ClosePWM();                         //关闭方波输出
void KeyScan();                            //按键扫描函数，需在定时中断中调用
void KeyDriver();                         //按键驱动函数，检测按键动作，调度相应动作函数，需在主循环中调用

void main()
{
unsigned int i;
EA = 1; //开总中断
while (1)
{
      //ConfigPWM(100, 5);             //频率100Hz，占空比10%
      for (i=0; i<40000; i++);          //不断发送ConfigPWM中的方波
      //ClosePWM();
      KeyScan();
      KeyDriver();
}
}
/* 配置并启动PWM，fr-频率，dc-占空比 */
void ConfigPWM(unsigned int fr, unsigned char dc)
{
unsigned int high, low;
unsigned long tmp;
tmp = (11059200/12) / fr;             //计算一个周期所需的计数值
high = (tmp*dc) / 100;                //计算高电平所需的计数值
low = tmp - high;                      //计算低电平所需的计数值
high = 65536 - high + 12;             //计算高电平的重载值并补偿中断延时
low = 65536 - low + 12;                //计算低电平的重载值并补偿中断延时
HighRH = (unsigned char)(high>>8);    //高电平重载值拆分为高低字节
HighRL = (unsigned char)high;
LowRH = (unsigned char)(low>>8);       //低电平重载值拆分为高低字节
LowRL = (unsigned char)low;
TMOD &= 0xF0;                         //清零T0 的控制位
TMOD |= 0x01;                         //配置T0 为模式1
TH0 = HighRH;                         //加载T0 重载值
TL0 = HighRL;
ET0 = 1;                               //使能T0 中断
TR0 = 1;                               //启动T0
PWMOUT = 1;                            //输出高电平
}
/* 关闭PWM */
void ClosePWM()
{
TR0 = 0;                               //停止定时器
ET0 = 0;                               //禁止中断
PWMOUT = 0;                            //输出低电平
}
/* 按键扫描函数，需在定时中断中调用 */
void KeyScan()
{
unsigned char i;
static unsigned char keybuf[4] = { //按键扫描缓冲区
0xFF, 0xFF, 0xFF, 0xFF
};
//按键值移入缓冲区
keybuf[0] = (keybuf[0] << 1) | KEY1;  //按键按下的时候，KEY会变成0XFF，使得keybuf = 0x00
keybuf[1] = (keybuf[1] << 1) | KEY2;
keybuf[2] = (keybuf[2] << 1) | KEY3;
//消抖后更新按键状态
for (i=0; i<3; i++)
{
      if (keybuf == 0x00)
      { //连续8 次扫描值为0，即16ms 内都是按下状态时，可认为按键已稳定的按下
         KeySta = 0;
      }
      else if (keybuf == 0xFF)
      { //连续8 次扫描值为1，即16ms 内都是弹起状态时，可认为按键已稳定的弹起
         KeySta = 1;
      }
}
}
/* 按键驱动函数，检测按键动作，调度相应动作函数，需在主循环中调用 */
void KeyDriver()
{
unsigned char i;
static unsigned char backup[4] = {1,1,1,1};//备份按键扫描
for (i=0; i<4; i++) //循环检测4 个按键
{
      if (backup != KeySta)       //检测按键动作
      {                                  //如果不一样，代表该按键已经被按下
         if (backup != 0)          //按键按下时执行动作
         {
            if (i == 0)                //按键为0，旋转-90
            {
                  ConfigPWM(50, 3); //频率50Hz，20ms,占空比10%
                  for (i=0; i<40000; i++);
                  ClosePWM();

            }
            else if (i == 1)          //按键为1，旋转0
            {
                  ConfigPWM(50, 8); //频率50Hz，20ms,占空比3%
                  for (i=0; i<40000; i++);
                  ClosePWM();
            }
            else if (i == 2)          //按键为0，旋转90
            {
                  ConfigPWM(50, 13);  //频率50Hz，20ms,占空比8%
                  for (i=0; i<40000; i++);
                  ClosePWM();
            }
         }
      backup = KeySta;             //刷新前一次的备份值
      }
}
}
/* T0 中断服务函数，产生PWM 输出 */
void InterruptTimer0() interrupt 1
{
//如果一开始是高，那么中断到了之后输出低即可完成PWM
if (PWMOUT == 1)                      //当前输出为高电平时，装载低电平值并输出低电平
{
      TH0 = LowRH;
      TL0 = LowRL;
      PWMOUT = 0;
}
//如果一开始是低，那么中断到了之后输出高即可开始产生PWM
else                                  //当前输出为低电平时，装载高电平值并输出高电平
{
      TH0 = HighRH;
      TL0 = HighRL;
      PWMOUT = 1;
}
}