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How can get input capture values from STM32F4 for measuring the duty cycles of the four different signal?

Here is one channel code:

uint32_t IC2Value,Frequency,miliseconds;
float DutyCycle;


static void TIM2_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  TIM_ICInitTypeDef  TIM_ICInitStructure;  
  /* TIM2 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

  /* GPIOB clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); //Change here, to GPIOA 

  /* TIM2 chennel2 configuration : PA1 */
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_0 | GPIO_Pin_1| GPIO_Pin_2 | GPIO_Pin_3  ;  //Change here, to pin 10
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP ;
  GPIO_Init(GPIOA, &GPIO_InitStructure);   //Change to GPIOA

  /* Connect TIM pin to AF2 */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource0, GPIO_AF_TIM2); //And change to pin 1
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_TIM2);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_TIM2);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_TIM2);
  /* Enable the TIM2 global Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

   /* --------------------------------------------------------------------------- 
    TIM2 configuration: PWM Input mode
     The external signal is connected to TIM2 CH2 pin (PB.03)
     TIM2 CCR2 is used to compute the frequency value 
     TIM2 CCR1 is used to compute the duty cycle value

    In this example TIM2 input clock (TIM2CLK) is set to APB1 clock (PCLK1), since
    APB1 prescaler is set to 1.
      TIM2CLK = PCLK1 = HCLK = SystemCoreClock

    External Signal Frequency = SystemCoreClock / TIM2_CCR2 in Hz.
    External Signal DutyCycle = (TIM2_CCR1*100)/(TIM2_CCR2) in %.
  Note: 
  SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f0xx.c file.
  Each time the core clock (HCLK) changes, user had to call SystemCoreClockUpdate()
  function to update SystemCoreClock variable value. Otherwise, any configuration
  based on this variable will be incorrect.
  --------------------------------------------------------------------------- */


  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_ICInitStructure.TIM_Channel = TIM_Channel_2; 
    TIM_ICInit(TIM2,&TIM_ICInitStructure);



    TIM_PWMIConfig(TIM2, &TIM_ICInitStructure);

  /* Select the TIM2 Input Trigger: TI2FP2 */
  TIM_SelectInputTrigger(TIM2, TIM_TS_TI2FP2);

  /* Select the slave Mode: Reset Mode */
  TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset);
  TIM_SelectMasterSlaveMode(TIM2,TIM_MasterSlaveMode_Enable);

  /* TIM enable counter */
  TIM_Cmd(TIM2, ENABLE);


  /* Enable the CC2 Interrupt Request */
   TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);
}
//And the Interrupt code: //I have changed nothing in it

void TIM2_IRQHandler(void)
{
  /* Clear TIM2 Capture compare interrupt pending bit */
  TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);

  /* Get the Input Capture value */
  IC2Value = TIM_GetCapture2(TIM2);

  if (IC2Value != 0)
  {
    /* Duty cycle computation */
    DutyCycle = (float)(TIM_GetCapture1(TIM2) * 100) / IC2Value;

    /* Frequency computation */
    Frequency = SystemCoreClock / IC2Value;

        miliseconds = DutyCycle*200;
  }
  else
  {
    DutyCycle = 0;
    Frequency = 0;
  }
}


int main()
{

    TIM2_Config();


    while(1){

        TIM2_IRQHandler();



    }
}
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  • 4
    \$\begingroup\$ Why are you calling an interrupt handler manually in your main loop? \$\endgroup\$ – Colin Jul 17 at 19:41
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Each signal would require it's own timer. Suitable timers must have at least 2 channels, slave mode (reset mode) for PWM input, and the pin for channel 1 or 2 available. Pick 3 more timers from the reference manual that meet these criteria, then adapt your config function for these.

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  • \$\begingroup\$ When I use different timer. I'm getting wrong values.What is the reason of taken incorrect values? \$\endgroup\$ – İlyas Sarıgül Jul 18 at 14:19
  • \$\begingroup\$ How could anyone know what's wrong with the modified code if you don't show it? \$\endgroup\$ – berendi Jul 20 at 6:33

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