WPM 输入捕获问题，本人理解是否有误，请大家指点

只看该作者 · 2013-9-7 22:53

/* TIM4 configuration: PWM Input mode ------------------------
   The external signal is connected to TIM4 CH2 pin (PB.07), //选择ch2口输入
   The Rising edge is used as active edge,
   The TIM4 CCR2 is used to compute the frequency value //捕获周期
   The TIM4 CCR1 is used to compute the duty cycle value//捕获占空比
  ------------------------------------------------------------ */
  TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;//上升沿捕获，  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;//设置端口ch1 ch2 ch3 ch4分别对应寄
                                                                                                //存器    ccr1 ccr2 ccr3 ccr4
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
  TIM_ICInitStructure.TIM_ICFilter = 0x0;
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;//上升沿捕获ch2通道对应寄存器ccr2 捕获上升沿的值，所以另一个ccr1对应就是下降沿捕获，如果对应寄存器配置相反的话捕获关系就相反了？我这样理解正确吗

1万 · 2013-9-8 07:42

由于用主从模式, 一个捕获周期, 一个捕获高电平(低电平)时间.

只看该作者 · 2013-9-8 08:59

airwill 发表于 2013-9-8 07:42
由于用主从模式, 一个捕获周期, 一个捕获高电平(低电平)时间.

怎样确定哪个一个寄存器捕获周期哪一个捕获高低电平？

只看该作者 · 2013-9-8 10:11

我已经找到问题答案了，其实这些操作都在配置函数里体现了如果你参数里选择了T1 作为输入，同样也在里面设置了TI2与他相反的设置代码如下：
void TIM_PWMIConfig(TIM_TypeDef* TIMx, TIM_ICInitTypeDef* TIM_ICInitStruct)
{
  uint16_t icoppositepolarity = TIM_ICPolarity_Rising;
  uint16_t icoppositeselection = TIM_ICSelection_DirectTI;

  /* Check the parameters */
  assert_param(IS_TIM_LIST2_PERIPH(TIMx));

  /* Select the Opposite Input Polarity */
  if (TIM_ICInitStruct->TIM_ICPolarity == TIM_ICPolarity_Rising)
  {
icoppositepolarity = TIM_ICPolarity_Falling;
  }
  else
  {
icoppositepolarity = TIM_ICPolarity_Rising;
  }
  /* Select the Opposite Input */
  if (TIM_ICInitStruct->TIM_ICSelection == TIM_ICSelection_DirectTI)
  {
icoppositeselection = TIM_ICSelection_IndirectTI;
  }
  else
  {
icoppositeselection = TIM_ICSelection_DirectTI;
  }
  if (TIM_ICInitStruct->TIM_Channel == TIM_Channel_1)
  {
/* TI1 Configuration */
TI1_Config(TIMx, TIM_ICInitStruct->TIM_ICPolarity, TIM_ICInitStruct->TIM_ICSelection,
            TIM_ICInitStruct->TIM_ICFilter);
/* Set the Input Capture Prescaler value */
TIM_SetIC1Prescaler(TIMx, TIM_ICInitStruct->TIM_ICPrescaler);
/* TI2 Configuration */
TI2_Config(TIMx, icoppositepolarity, icoppositeselection, TIM_ICInitStruct->TIM_ICFilter);
/* Set the Input Capture Prescaler value */
TIM_SetIC2Prescaler(TIMx, TIM_ICInitStruct->TIM_ICPrescaler);
  }
  else
  {
/* TI2 Configuration */
TI2_Config(TIMx, TIM_ICInitStruct->TIM_ICPolarity, TIM_ICInitStruct->TIM_ICSelection,
            TIM_ICInitStruct->TIM_ICFilter);
/* Set the Input Capture Prescaler value */
TIM_SetIC2Prescaler(TIMx, TIM_ICInitStruct->TIM_ICPrescaler);
/* TI1 Configuration */
TI1_Config(TIMx, icoppositepolarity, icoppositeselection, TIM_ICInitStruct->TIM_ICFilter);
/* Set the Input Capture Prescaler value */
TIM_SetIC1Prescaler(TIMx, TIM_ICInitStruct->TIM_ICPrescaler);
  }
}

WPM 输入捕获问题，本人理解是否有误，请大家指点

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