想请教关于pwm控制电机的问题 -

标题: 想请教关于pwm控制电机的问题 [打印本页]

作者: callmesbplease 时间: 2019-11-18 13:11
标题: 想请教关于pwm控制电机的问题
题主写了一个程序来测速，想用pwm来控制电机快慢，但是在keil仿真后发现，pwm产生了0.2314s后自动停止，不知道是哪方面的原因，自己觉得是其他中断打断了pwm产生的中断，但是又不知道是怎么回事，还有该怎么改代码，想请教一下大家，谢谢

#include<reg51.h>
//#include<intrins.h>
#define uch unsigned char
#define uin unsigned int

uch code table[]="Duty Ratio:";
uch code able[]="Rev:";
uin count,countt,rad,f,t,g,s,b,q,w;
uin b = 0;
uin PWM_T = 0; //占空比控制变

sbit rs=P1^2;
sbit rw=P1^1;
sbit en=P1^0;

sbit down = P1^5;
sbit up = P1^6;
sbit fan=P1^4;

void delay(uin time)
{
uin i,j;
for(i=time;i>0;i--)
      for(j=120;j>0;j--);
}

void time0()
{

TMOD=0x21;

TH0=0xdc;
TL0=0x00;
ET0=1;
TR0=1;

IT1=1;
EX1=1;
// EA=1;

TH1=255;    //写入预置初值（取值1-255，数越大PWM频率越高）
TL1=255;    //写入预置值（取值1-255，数越大PWM频率越高）
ET1=1;       //允许定时器0中断
TR1=1;    //启动定时器

EA=1;       //允许总中断
fan=0xff;    //初始化输出端口
PWM_T=50;
}

//uch lcd_readbusy()
//{
// uch temp;
// rs=0;
// rw=1;
// _nop_();
// P2=0xff;
// _nop_();
// en=1;
// _nop_();
// temp=P2;
// _nop_();
// en=0;
// return(temp&0x80);
//}
void write_com(uch com)
{
while(lcd_readbusy());
rs=0;
rw=0;
P2=com;
delay(5);
en=1;
delay(10);
en=0;
}
void write_data(uch dat)
{
while(lcd_readbusy());
rs=1;
rw=0;
P2=dat;
delay(5);
en=1;
delay(5);
en=0;
}
void display1() {

countt=count/3;
f=count*10/3%10;
g=countt%10;
s=(countt/10)%10;
b=(countt/100)%10;
q=(countt/1000)%10;
w=countt/10000;

write_com(0xc0+5);
write_data(w+0x30);  //万位
write_com(0xc0+6);
write_data(q+0x30); //千位
write_com(0xc0+7);
write_data(b+0x30); //百位
write_com(0xc0+8);
write_data(s+0x30); //十位
write_com(0xc0+9);
write_data(g+0x30); //个位
write_com(0xc0+11);
write_data(f+0x30); //浮点位
}
void init()
{ uin i=0;

write_com(0x38);
write_com(0x0c);
write_com(0x01);

write_com(0x80);
      for(i=0;i<11;i++)
{
      write_data(table[i]);
}
write_com(0x80+15);
write_data('%');

write_com(0xc0);
for(i=0;i<4;i++)
{
      write_data(able[i]);
}

write_com(0xc0+10);
write_data('.');
write_com(0xc0+13);
write_data('R');
write_data('P');
write_data('S'); // 转每秒

}
//void button()
//{
//    if(!up)
//          {
//             if(PWM_T<250)
//                   {
//                   PWM_T++;
//                   }
//
//             delay(10);
//          }
//       if(!down)
//          {
//             if(PWM_T>0)
//                   {
//                   PWM_T--;
//                   }
//
//             delay(10);
//          }
//}
void main()
{
// init();
time0();
count=0;
t=0;
b=0;

while(1)
{
//       button();

}
  }
writerdown_time1() interrupt 2
{
count++;
}
taker_time2() interrupt 1
{
t++;
TH0=0xdc;
TL0=0x00;
if(t==200)
{
      display1();
      count=0;
      t=0;
}
}
time3() interrupt 3
{
      b++; //每次定时器溢出加1

   if(b==250) //PWM周期 100个单位
      {
            b=0;  //使t=0，开始新的PWM周期
            fan=0x00;  //输出端口
      }

   if(PWM_T==b)  //按照当前占空比切换输出为高电平
      {
         fan=0xff;       //
      }
}

作者: pcbboy 时间: 2019-11-19 08:52
用硬件PWM吧

作者: pcbboy 时间: 2019-11-19 08:54
#include "stc15w.h"
#include  <intrins.h>
#include "pwm.h"

unsigned char  off_mark _at_(0x36);
unsigned char  DUTY5 _at_(0x37);
unsigned char  ir_code _at_(0x3d);//

unsigned char SYSTEM_TIM0 _at_(0x65);
unsigned char SYSTEM_TIM1 _at_(0x66);
//==========================================================*/
void PWM_config(void)
{

P_SW2 |= 0x80;

PWMCKS = 0x00;
PWMC = CYCLE;                //设置PWM周期

PWM5T1 = 1;
PWM5T2 = 0;
PWM5CR = 0x00;                //0x00 PWM5输出到P2.3  //  0x08 pwm5输出到4.2

PWMCFG = 0x00;                //配置PWM的输出初始电平为低电平
PWMCKS = 0x00;                //选择PWM的时钟为Fosc/(0+1)
PWMC = CYCLE;                //设置PWM周期       //设置PWM周期

   PIN_SW2 |= 0x80;             //使能访问XSFR

DUTY5= 2;

   PWM5T1 = 0x0000;                //设置PWM2第1次反转的PWM计数
PWM5T2 = CYCLE * DUTY5 / 255; //设置PWM2第2次反转的PWM计数//占空比为(PWM2T2-PWM2T1)/PWMC

PWMCR = 0x01;                //使能PWM信号输出    //01 /01000001
  PWMCR |= 0x80;                //使能PWM模块
//PWMCR |= 0x01;             //ch2
//PWMCR |= 0x02;             //ch3
//PWMCR |= 0x04;             //ch4
PWMCR |= 0x08;             //ch5
//PWMCR |= 0x10;             //ch6
//PWMCR |= 0x20;             //ch7

   PIN_SW2 &= ~0x80;             //xx访问XSFB
}
//==============================================================
//函数:void PWM_updata(void)
//描述:pwm 数据处理
//功能:
//调试:    ok
//==============================================================
void PWM_updata(void)
{
   PIN_SW2 |= 0x80;                //使能访问XSFR

   PWM5T1 = 0x0000;                //设置PWM2第1次反转的PWM计数
PWM5T2 = CYCLE * DUTY5 / 255; //设置PWM2第2次反转的PWM计数//占空比为(PWM2T2-PWM2T1)/PWMC
   PWMCR |= 0x08;                //ch5

   PIN_SW2 &= ~0x80;                //xx访问XSFR    */

   PWM_updata_ON_OFF();
}

//=========================================================================
//函数: void PWM_updata_ON_OFF(void)
//功能:PWM 数值判断是否需要关闭PWM输出端为0，PWM开关控制
//=========================================================================
void PWM_updata_ON_OFF(void)
{

  if(DUTY5 <= 0x03)
{
   PWMCR &=~ 0x08;
   PWM5= 0;
off_mark=0;
}
else if(DUTY5 >= 0x0fe)
{
   PWMCR &=~ 0x08;
   PWM5= 1;
off_mark=1;
}
else
{
   PIN_SW2 |= 0x80;
PWM5T2 = CYCLE * DUTY5 / 255;//设置PWM2第2次反转的PWM计数//占空比为(PWM2T2-PWM2T1)/PWMC
   off_mark=2;
PIN_SW2 &=~ 0x80;

   PWMCR |= 0x08;
}

}

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