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Problem with Input Capture in STM32F103RBT6

Question asked by amer.sherif on Aug 22, 2011
Latest reply on Aug 25, 2011 by amer.sherif
Hi all!

I'm using STM32F103RBT6, board Olimex STM32-H103 and i'm trying to create an IR receiving firmware.

I'm using Input Capture mode TIM1-Channel1 with the specs below:

    TIM_ICInitTypeDef  TIM_ICInitStructure;

    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;
    TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM_ICInitStructure.TIM_ICFilter = 0xf;
    TIM_ICInit(TIM1, &TIM_ICInitStructure);

    /* Enable the CC1 Interrupt Request */

    /* TIM1 enable counter */
    TIM_Cmd(TIM1, ENABLE);


and the NVIC specs:


    NVIC_InitTypeDef NVIC_InitStructure;

    /* 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;


The problem is:
the TIM1 CC interrupt handler is being called every time i connect the PA.8 (which is internally linked to TIM1-CH1) with a floating wire.