PWM输入脉宽检测的问题

只看该作者 · 2015-6-2 19:40

信号发生器间隔发送1us和5us的脉冲，stm32可以正确检测到所有的脉冲宽度。但当把1us的脉冲宽度减少到700ns时，5us和700ns的脉冲宽度都检测为700ns了，有遇到过这个问题的吗？

1万 · 2015-6-3 08:01

不应该出现这样的问题, 定时器的脉冲检测功能不用怀疑. 值得怀疑的是你的设置, 还有你的信号. 用示波器验证吧.

只看该作者 · 2015-6-3 08:27

airwill 发表于 2015-6-3 08:01
不应该出现这样的问题, 定时器的脉冲检测功能不用怀疑. 值得怀疑的是你的设置, 还有你的信号. 用示波器验证 ...

{
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
TIM_ICInitTypeDef  TIM_ICInitStructure;

  /* TIM4 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

  /* GPIOB clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

  /* TIM4 chennel2 configuration : PB.07 */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOD, &GPIO_InitStructure);

  /* Connect TIM pin to AF2 */
  GPIO_PinAFConfig(GPIOD, GPIO_PinSource13, GPIO_AF_TIM4);

  /* Enable the TIM4 global Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
  TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
  TIM_ICInitStructure.TIM_ICFilter = 0x0;

  TIM_PWMIConfig(TIM4, &TIM_ICInitStructure);

  /* Select the TIM4 Input Trigger: TI2FP2 */
  TIM_SelectInputTrigger(TIM4, TIM_TS_TI2FP2);

  /* Select the slave Mode: Reset Mode */
  TIM_SelectSlaveMode(TIM4, TIM_SlaveMode_Reset);
  TIM_SelectMasterSlaveMode(TIM4,TIM_MasterSlaveMode_Enable);

  /* TIM enable counter */
  TIM_Cmd(TIM4, ENABLE);

  /* Enable the CC2 Interrupt Request */
TIM_ITConfig(TIM4, TIM_IT_CC2, ENABLE);

}