Timer interrupt Question

[lizerd]

Posted on November 29, 2010 at 09:31

Timer interrupt Question

[Tesla DeLorean]

Posted on May 17, 2011 at 14:16

Third question:

 

Is this the best way to go for a simple time based interrupt routine ??

 

Well define ''best''. What period do you want, is it continuous or variable, etc.

SysTick is pretty simple. The RTC can go sub-second with the appropriate scale. The TIMx timers can be a lot simpler than you have presented if you just want a constant periodic interrupt ticker.

[lowpowermcu]

Posted on May 17, 2011 at 14:16

Hi,

You need to configure the time base, enable update interrupt and configure the NVIC.

Add 

   /* TIM update IT enable */

  TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

Remove from configuration:

/********    satrt                 *******/

  /* Output Compare Timing Mode configuration: Channel1 */

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Timing;

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  TIM_OCInitStructure.TIM_Pulse = 3000;

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  TIM_OC1Init(TIM2, &TIM_OCInitStructure);

  TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Disable);

  /* TIM IT enable */

  TIM_ITConfig(TIM2, TIM_IT_CC1, ENABLE);

/********   end                 *******/

/* !!!!!!!!!!!!!!!!!!!!! Don't remove this!!!!!!!!!!!!!!!!!!!!!!!!!!! */

  /* TIM2 enable counter */

  TIM_Cmd(TIM2, ENABLE);

In the timer interrupt, as you said you need to clear the interrupt

change

void TIM2_IRQHandler(void)

{

  if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)

  {

    TIM_ClearITPendingBit(TIM2, TIM_IT_CC1);

    capture = TIM_GetCapture1(TIM2);

    TIM_SetCompare1(TIM2, capture + 3000);

     // Main Clock Timer

    Timer_mSec++;

    if(Timer_mSec == 1000)

    {

        Timer_mSec = 0;

        Timer_Sec++;

        if(Timer_Sec == 60)

        {

            Timer_Sec = 0;

            Timer_Min++;

        }

    }

  }

  TestTime++;

}

by

void TIM2_IRQHandler(void)

{

  if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)

  {

     // Main Clock Timer

    Timer_mSec++;

    if(Timer_mSec == 1000)

    {

        Timer_mSec = 0;

        Timer_Sec++;

        if(Timer_Sec == 60)

        {

            Timer_Sec = 0;

            Timer_Min++;

        }

    TIM_ClearITPendingBit(TIM2, TIM_IT_Update);

  }

}

Remark:   TIM_OC1Init() configures Output Compare channel: pwm1, pwm2

[lizerd]

Posted on May 17, 2011 at 14:16

i am using the SysTick already, so i have learned how to use the SysTick.

But now i trying to master the ''Normal'' Timer interrupt.

So right now i trying to find a simple interrupt based on the TIM timers.

I have checked and tested some of the timer example. but i did not find any one that is a simple interrupt based timer.

Lets say. a timer that go´s into interrupt every 1ms

I haven´t tested

code yet,

[Tesla DeLorean]

Posted on May 17, 2011 at 14:16

For the VL Discovery a simple implementation with blinking LEDs

void TIM2_IRQHandler(void)

{

  if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)

  {

    TIM_ClearITPendingBit(TIM2, TIM_IT_Update);

    /* Whatever */

    STM32vldiscovery_LEDToggle(LED3);

  }

}

int main(void)

{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

  NVIC_InitTypeDef NVIC_InitStructure;

  /* Initialise LEDs LD3&LD4, both off */

  STM32vldiscovery_LEDInit(LED3);

  STM32vldiscovery_LEDInit(LED4);

  STM32vldiscovery_LEDOff(LED3);

  STM32vldiscovery_LEDOff(LED4);

  /* Enable the TIM2 gloabal Interrupt */

  NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

  /* TIM2 clock enable */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

  /* VL clocks at 24 MHz, change to 72 - 1 for a 72 MHz system

  /* Time base configuration */

  TIM_TimeBaseStructure.TIM_Period = 1000 - 1;  // 1 MHz down to 1 KHz (1 ms)

  TIM_TimeBaseStructure.TIM_Prescaler = 24 - 1; // 24 MHz Clock down to 1 MHz (adjust per your clock)

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

  /* TIM IT enable */

  TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

  /* TIM2 enable counter */

  TIM_Cmd(TIM2, ENABLE);

  while (1);

}