定时器级联

爱奔跑的IT · 发表于 2017-10-19 17:20:02

本帖最后由爱奔跑的IT 于 2017-10-19 17:26 编辑
现在用F407控制四个电机，想用一组定时器级联一个产生PWM一个计数实现输出特定数目的PWM波，但是现在遇到输出的PWM波正常但是不能计数到指定的数目后停止产生，看了一天的手册，搞到现在还是没有成功，希望有经验的前辈能指导一下，非常感谢了。
定时器2做主定时器3做从定时器计数：
思路：主定时器产生一个触发信号（脉冲），让从定时器去接收这个触发信号并计数，达到目标的PWM脉冲数后失能两个计数器
参考别人代码如下：定时器级联参考代码
自己的代码如下：
[mw_shl_code=c,true]void TIM2_PWM_Init(u32 arr,u32 psc)
{

      GPIO_InitTypeDef GPIO_InitStructure;
      TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
      TIM_OCInitTypeDef  TIM_OCInitStructure;

      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);       //初始化定时器2时钟
      RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);       //初始化GPIOA

      GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_TIM2); //定时器2复用

      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;          //GPIOA
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;       //¸´ÓÃ¹¦ÄÜ
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;       //ËÙ¶È100MHz
      GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;    //ÍÆÍì¸´ÓÃÊä³ö
      GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;       //ÉÏÀ
      GPIO_Init(GPIOA,&GPIO_InitStructure);             //PA0初始化

      TIM_TimeBaseStructure.TIM_Prescaler=psc;  //定时器分频
      TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数
      TIM_TimeBaseStructure.TIM_Period=arr; //自动重装载值
      TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;

      TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);//初始化定时器2

      TIM_UpdateRequestConfig(TIM2,TIM_UpdateSource_Regular); /*********只有计数溢出作为更新中断********/


      //设置TIM14 Channel1 PWM模式
      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //脉冲宽度调制模式1
      TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //使能输出使能
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性高
      TIM_OCInitStructure.TIM_Pulse = arr>>1;       //50%占空比
      TIM_OC1Init(TIM2, &TIM_OCInitStructure);  //初始化TIM_OC1

      TIM2->CR2 |=0x2<<4;  //配置主模式MMS=010

      TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);  //使能TIM2在CCR1上的预装载寄存器

  TIM_ARRPreloadConfig(TIM2,ENABLE);//ARPE使能

      TIM_Cmd(TIM2, ENABLE);  //使能TIM2
}
void TIM3_PWM_Init(u32 arr,u32 psc)
{

      TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
      NVIC_InitTypeDef NVIC_InitStructure;

      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);  ///使能TIM3时钟



      TIM3->SMCR |= 0x01<<4;  //触发选择内部触发1(ITR1)TIM2
      TIM3->SMCR |= 0x07<<0;  //选中的触发输入为定时器计数时钟



      TIM_TimeBaseInitStructure.TIM_Period = arr;       //自动重装载值
      TIM_TimeBaseInitStructure.TIM_Prescaler=psc;  //定时器分频
      TIM_TimeBaseInitStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式
      TIM_TimeBaseInitStructure.TIM_ClockDivision=TIM_CKD_DIV1;

      TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStructure);//初始化TIM3

      TIM_SelectOnePulseMode(TIM3,TIM_OPMode_Single);/******* 单脉冲模式**********/

      TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE); //使能计数器更新中断

      NVIC_InitStructure.NVIC_IRQChannel=TIM3_IRQn; //定时器3中断
      NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0x01; //抢占优先级1
      NVIC_InitStructure.NVIC_IRQChannelSubPriority=0x03; //子优先级3
      NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
      NVIC_Init(&NVIC_InitStructure);

      TIM_Cmd(TIM3,ENABLE); //使能定时器3
}

void TIM3_IRQHandler(void)
{
      if (TIM_GetITStatus(TIM3, TIM_IT_Trigger) != RESET)  //检查是否产生中断
      {
            TIM_ClearITPendingBit(TIM3, TIM_IT_Trigger); // 清除中断

            TIM_Cmd(TIM2, DISABLE); // 失能定时器2
            TIM_Cmd(TIM3, DISABLE); // 失能定时器3
      }
}[/mw_shl_code]