STM32F103RB TIM1 INPUT CAPTURE QUESTION?

[taurus3g]

Posted on September 28, 2011 at 18:33

hi, dear Frs.

  now i want use the TIM1 ch1,ch2 to decode rf decoded . which is rf encode is diphase coded.  i use the PA8 use rf data stream input pin.  rf datarate is 9.6k.   now i step steps is as belows:

static void GPIO_Configuration(void)

{

  GPIO_InitTypeDef GPIO_InitStructure;

       /*GPIOA Configuration: TIM1 channel 1&2 as alternate function push-pull */   /*GPIOA pin8/9 as general input */   GPIO_InitStructure.GPIO_Pin   =  GPIO_Pin_8 | GPIO_Pin_9;   GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_IPU; //GPIO_Mode_IN_FLOATING;   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

}

static void NVIC_Configuration(void)

{   NVIC_InitTypeDef NVIC_InitStructure;

  /* Enable the TIM1 gloabal 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);

}

static void RF_TIM1Init(void)

{   

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1||RCC_APB2Periph_GPIOA, ENABLE);

   GPIO_Configuration();

 TIM_DeInit(TIM1);

      /* -----------------------------------------------------------------------     TIM1 Configuration:capture  40--200us signals with different duty cycles:     TIM1CLK = 72 MHz, Prescaler = 0x0, TIM3 counter clock = 72MHz     TIM1 ARR Register = 72 => TIM1 Frequency = TIM1 counter clock/(ARR + 1)     TIM1 Frequency = 1us(1MHZ).   ----------------------------------------------------------------------- */           /* Time base configuration */      TIM_TimeBaseStructure.TIM_Period = 65535;      TIM_TimeBaseStructure.TIM_Prescaler = 72;      TIM_TimeBaseStructure.TIM_ClockDivision = 0;      TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  

  TIM_TimeBaseInit(TIM1,&TIM_TimeBaseStructure);

  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 = 2;   TIM_ICInit(TIM1,&TIM_ICInitStructure);

  TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;

  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;   TIM_ICInitStructure.TIM_ICSelection  = TIM_ICSelection_IndirectTI;   TIM_ICInitStructure.TIM_ICPrescaler  = TIM_ICPSC_DIV1;

  TIM_ICInit(TIM1,&TIM_ICInitStructure);

  TIM_ClearFlag(TIM1, TIM_FLAG_CC1||TIM_FLAG_CC2);

  TIM_ITConfig(TIM1,TIM_IT_CC1||TIM_IT_CC2,ENABLE);

  NVIC_Configuration();   TIM_ARRPreloadConfig(TIM1, ENABLE);   TIM_CCxCmd(TIM1,TIM_Channel_1||TIM_Channel_2,ENABLE);   TIM_Cmd(TIM1, ENABLE);

}

but the can not enter the TIM1 cc1 intterupt isr. i check the NVIC. the  #tim1-input-capture

[Tesla DeLorean]

Posted on September 28, 2011 at 19:25

Observations :

     TIM_TimeBaseStructure.TIM_Prescaler = 72; This needs to be 71 (ie N-1) to do what you want. ie get 1 MHz from 72 MHz     RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1||RCC_APB2Periph_GPIOA, ENABLE); You keep using '||' throughout your code, where the single '|' OR is supposed to be used.