单片机调pwm,占空比和频率

ID:999069 · 发表于 2022-1-1 19:59

#include <reg52.h>
typedef unsigned char uint8;
typedef unsigned int  uint16;//数据类型重定义

uint8 count = 0; //计进入外部中断次数
bit flag = 1;  //捕获结束标志位
long Pwm_All; //PWM的周期
long Pwm_High; //PWM的高电平时间                占空比=Pwm_High/Pwm_All
void delay(long i)
{
      while(i--);
}

void Interrupt_Init()
{
      /*定时器1为工作模式1 16位计数器由TR1直接启动
            定时器0为工作模式1 16位计数器由GATE和TR0共同启动*/
      TMOD = 0x19;

      TH1 = 0;
      TL1 = 0;
      TH0 = 0;
      TL0 = 0;

      IT0 = 1;//下降沿触发
      IT1 = 1;
      //TR0 = 1; //GATE高电平启动

      EX0 = 1;
      EA = 1;
}

void main()
{
      uint16 Pwm_percentage; //PWM占空比
      Interrupt_Init();
      LCD1602_Initialize( );
      LCD1602_PrintString(1,1,"ALL:");
      LCD1602_PrintString(1,10,"us");
      LCD1602_PrintString(2,1,"HIGH:");
      LCD1602_PrintString(2,11,"us");
      while(1)
      {

            if(flag)
            {
                     Pwm_percentage = Pwm_High*1000 / Pwm_All;
                     LCD1602_PrintChar(1,12,0x30+Pwm_percentage/100);
                     LCD1602_PrintChar(1,13,0x30+Pwm_percentage%100/10);
                     LCD1602_PrintChar(1,14,'.');
                     LCD1602_PrintChar(1,15,0x30+Pwm_percentage%10);
                     LCD1602_PrintChar(1,16,'%');

                     LCD1602_PrintChar(1,5,0x30+Pwm_All/10000);
                     LCD1602_PrintChar(1,6,0x30+Pwm_All%10000/1000);
                     LCD1602_PrintChar(1,7,0x30+Pwm_All%1000/100);
                     LCD1602_PrintChar(1,8,0x30+Pwm_All%100/10);
                     LCD1602_PrintChar(1,9,0x30+Pwm_All%10);
                     LCD1602_PrintChar(2,6,0x30+Pwm_High/10000);
                     LCD1602_PrintChar(2,7,0x30+Pwm_High%10000/1000);
                     LCD1602_PrintChar(2,8,0x30+Pwm_High%1000/100);
                     LCD1602_PrintChar(2,9,0x30+Pwm_High%100/10);
                     LCD1602_PrintChar(2,10,0x30+Pwm_High%10);
                     flag = 0; //计算完一次清零
            }
            delay(70000);
      }

}

void EXTI0 () interrupt 0
{
            count++;
      if(count == 1) //第一次下降沿，启动定时器1
      {
            TR1 = 1;
            TR0 = 1;
      }
      if(count == 2) //第二次下降沿，一整个周期完毕
      {
            EX0 = 0; //关闭外部中断，防止被其他打断计算
            TR1 = 0;       //周期停止计数
            TR0 = 0;       //高电平时间停止计数
            Pwm_All = TH1; //获取数据
            Pwm_All = (Pwm_All<<8)+TL1;
            Pwm_High = TH0;
            Pwm_High = (Pwm_High<<8)+TL0;
            TH1 = 0; //清零为下一次做准备
            TL1 = 0;
            TH0 = 0;
            TL0 = 0;
            count = 0;
            flag = 1;
            EX0 = 1; //开启下一次计算
            TR1 = 0;
            TR0 = 0;
      }

}

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单片机调pwm,占空比和频率

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