STM32F437 timer input capture

[John Hite]

Posted on March 16, 2017 at 20:16

I have attempted to set up timer 4 channel 1 for input capture but unsuccessfully. The scope indicates that my 1KHz, 3vdc, 35 uSec pulses are making it to PD12 (TIM4, ch 1). However, CC1IF is never set. Although channels 2-4 are not configured CC2IF - CC4IF are being set and thus so is UIF but my ISR is never called. So I have two problems no CC1IF and no call to the ISR. Suggestions and advice would be much appreciated. The code follows.

Thanks,

JH

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

uint32_t rpm4;

void RpmTask(void  *p_arg);

void RpmTask(void *p_arg)

{    static int i = 0;    uint16_t itstatus = 0;

    GPIO_StructInit(&GPIO_InitStruct);

    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_12;    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;    GPIO_InitStruct.GPIO_Speed = GPIO_High_Speed;    GPIO_Init(GPIOD, &GPIO_InitStruct);    GPIO_PinAFConfig(GPIOD, GPIO_PinSource12, GPIO_AF_TIM4);

    NVIC_InitTypeDef NVIC_InitStruct;

    NVIC_InitStruct.NVIC_IRQChannel = TIM4_IRQn;    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 1;    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;    NVIC_Init(&NVIC_InitStruct);

    //RPM timer setups

    // APB1PeriphClock - 42 MHz    // APB2PeriphClock - 84 MHz    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3 | RCC_APB1Periph_TIM4, ENABLE);    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_TIM9, ENABLE);

    TIM_TimeBaseInitTypeDef tim4_base;

    tim4_base.TIM_Period = 0xFFFFFFFF;    tim4_base.TIM_Prescaler = 48;    tim4_base.TIM_ClockDivision = TIM_CKD_DIV1;  //digital filter clk div, don't care, filtering is off    tim4_base.TIM_CounterMode = TIM_CounterMode_Up;    tim4_base.TIM_RepetitionCounter = 0; //t1&t8 pwm, don't care     TIM_TimeBaseInit(TIM4, &tim4_base);

    TIM_ICInitTypeDef tim4_icInit;

    tim4_icInit.TIM_Channel = TIM_Channel_1;    tim4_icInit.TIM_ICPolarity = TIM_ICPolarity_Rising; //r, f, both    tim4_icInit.TIM_ICSelection = TIM_ICSelection_DirectTI; //dir, ind, trc    tim4_icInit.TIM_ICPrescaler = TIM_ICPSC_DIV1; //1-8    tim4_icInit.TIM_ICFilter = 0x0;    TIM_ICInit(TIM4, &tim4_icInit);

    /* Enable the CC2 Interrupt Request */

    TIM_ITConfig(TIM4, TIM_IT_CC1, ENABLE);

    /* TIM enable counter */

    TIM_Cmd(TIM4, ENABLE);

    while (1)

    {        rpm4 = TIM_GetCounter(TIM4);        itstatus = TIM4->SR;    }}

void timer4_isr(void)

{    if (TIM_GetITStatus(TIM4, TIM_IT_CC1) == SET) {        TIM_ClearITPendingBit(TIM4, TIM_IT_CC1);        rpm4 = TIM_GetCounter(TIM4);    }

    TIM_ClearITPendingBit(TIM4, TIM_IT_Update);

}#input-capture

[waclawek.jan]

Posted on March 16, 2017 at 20:48

Post the content of relevant GPIO and TIM registers.

Did you observe the input signal directly on the MCU pin?

JW

[John Hite]

Posted on March 16, 2017 at 21:35

First perhaps I should have stated that I am trying to measure RPM counting the time between pulses.

Yes I piled on two pair of reading glasses and put my scope probe right on pin 81 of the 144 pin package.

I will collect the registers now. The TIM4 registers are below. Which GPIO registers would be useful?

cr1        0x0001    

cr2        0x0000    dier        0x0002    sr            0x001D    egr         0x0000    ccmr1    0x0001    ccmr2    0x0000    ccer        0x0001    psc          0x0064    arr          0xFFFF    ccr1        0x0000    ccr2        0x0000   

[John Hite]

Posted on March 16, 2017 at 22:07

Figured out how to get the watch list to give me GPIOD...

gpiod            0x40020C00

MODER        0x5455555AOTYPER        0x00000000OSPEEDR    0x0000000FPUPDR            0x00000000IDR                0x0000000BODR                0x00000008BSRRL            0x0000        BSRRH            0x0000        LCKR            0x00000000AFR    <array>                [0]    0x00000099            [1]    0x00020000   

[waclawek.jan · Accepted solution]

Posted on March 17, 2017 at 00:37

Timer registers look all OK (FYI checked in this order: CCMR1.CC1S if set to 'straight in'; CCER.CC1E if set to enable; DIER.CC1IE if set to enable).

Went to the GPIO registers, this was the very first to check:

MODER        0x5455555A

Lower two bits of that nibble are 00 which means that MODE of pin 12 is *not* AF as it is supposed to be, but In.

Now going in reverse:

GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;

I don't 'library' but this is probabaly the culprit.

JW

[John Hite]

Posted on March 17, 2017 at 13:40

JW,

Yes, that was it! Thank you very much for taking the time to look through all my register settings, I know that took some time.

I inherited the GPIO from a 'working' sister project and I assumed that all of the GPIO settings were correct as they have been until now. This is my mistake, I blame no one but myself for failing to see this.

Thank you again,

JH