AnsweredAssumed Answered

capturing frequency

Question asked by yazdansepas.iman on Feb 13, 2013
Latest reply on Feb 14, 2013 by yazdansepas.iman
Hi guys 
I'm working on a project, I need to fine filing edge of a stream with 4.000 Mhz  frequency.This is my code and IRQ sub program:
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;


  /* TIM1 clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);


  /* GPIOA clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);


  /* TIM1 channel 2 pin (PE.11) configuration */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_11 ;
  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(GPIOE, &GPIO_InitStructure);


  /* Connect TIM pins to AF2 */
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource11, GPIO_AF_TIM1);


  /* Enable the TIM1 global Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_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 = 0;
      Delay(0x3FFFFF);
      TIM_ICInit(TIM1, &TIM_ICInitStructure);
      /* TIM enable counter */
      TIM_Cmd(TIM1, DISABLE);
     //BLF=10144;
     //BLF=24806;
      /* Enable the CC2 Interrupt Request */
TIM_Cmd(TIM1, ENABLE);
TIM_ITConfig(TIM1, TIM_IT_CC2, ENABLE);
TIM_ICInit(TIM1, &TIM_ICInitStructure);
void TIM1_CC_IRQHandler(void)
{
     Array1[index0] =TIM1->CCR2;                        
     if(++index0>=60) index0=0;
     TIM_ClearITPendingBit(TIM1, TIM_IT_CC2);
}

but i couldn't measure 4 Mhz.
please help me
thank you
  

Outcomes