Configure the timers count at 32-bit

[u23]

Posted on July 18, 2014 at 08:39

Hi,

I'm using the device STM32F030C8T6 that has all the timers count at 16-bit.

I need using the timer count at 32-bit.

In the data sheet in the page 67 reads ''Maximum possible count with 32-bit counter''.

How can I configure the timer to count up to 32-bit?

Thanks

[Tesla DeLorean]

Posted on July 18, 2014 at 15:19

Some STM32F0 parts have a 32-bit counter, the part you have chosen does not.

You'd need to cascade at pair of 16-bit counters in master/slave mode

This might be illustrative

STM32F10x_StdPeriph_Lib_V3.5.0\Project\STM32F10x_StdPeriph_Examples\TIM\Cascade_Synchro

[u23]

Posted on July 18, 2014 at 16:22

Ok, Thanks

[u23]

Posted on July 21, 2014 at 09:44

I have configurated the TIM2 and TIM3 in cascade mode:

uint8_t TIMER_ConfigSynchInCascade( void )

{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

    TIM_OCInitTypeDef  TIM_OCInitStructure;

 

    /* TIM2 and TIM3 clock enable */

    // --------------------------------------------------------------------------

    RCC_APB2PeriphClockCmd(RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM3, ENABLE);

    

    /* Time base configuration */

    // --------------------------------------------------------------------------

  TIM_TimeBaseStructure.TIM_Period = 65535;

  TIM_TimeBaseStructure.TIM_Prescaler = 15;

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* Select the Master Slave Mode */

  TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);

  /* Master Mode selection */

  TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);

  /* Slave Mode selection: TIM3 */

  TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Gated);

  TIM_SelectInputTrigger(TIM3, TIM_TS_ITR1);

  /* TIM enable counter */

  TIM_Cmd(TIM3, ENABLE);

  TIM_Cmd(TIM2, ENABLE);

    return 0;

}

I

n the main function

, the LED4

is

turned on and off

in the following mode:

static __IO uint8_t Debug = 0;

#define LEDToggleValue ((uint32_t) 100000)

static __IO uint32_t CounterTimers = 0;

int main(void)

{

   /* Initialize Leds mounted on STM3210X-EVAL board */

  STM_EVAL_LEDInit(LED4);

  // Configura i timers in cascata

  TIMER_ConfigSynchInCascade();

  while (1)

  {

            // Toggle led

            CounterTimers = TIMER_GetCounter(TIM2)+TIMER_GetCounter(TIM3);

            if (  CounterTimers > LEDToggleValue )

                STM_EVAL_LEDOn(LED4);

            else    

                STM_EVAL_LEDOff(LED4);

    }

}

The LED4 is ever off!

I have

done something wrong

in the configuration

?

Thanks

[maxime]

Posted on July 21, 2014 at 16:11

Hi, 

Not sure but I think you should use :

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM3, ENABLE); instead of RCC_APB2PeriphClockCmd(RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM3, ENABLE);

[Tesla DeLorean]

Posted on July 21, 2014 at 17:34

CounterTimers = TIMER_GetCounter(TIM2)+TIMER_GetCounter(TIM3);

Does these functions deal with shifting the 16-bit word suitably?

[u23]

Posted on July 22, 2014 at 08:45

I have corrected the errors, but the timer TIM3 not counter!

The TIMER_GetCounter(TIM2) function return the value in the range [0÷65535], but the TIMER_GetCounter(TIM3) function return zero.

[u23]

Posted on July 24, 2014 at 08:38

The solution is descript below:

uint8_t TIMER_ConfigSynchInCascade( void )

{

    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

    uint16_t PrescalerValue_RPM = 0;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM16 | RCC_APB2Periph_TIM17, ENABLE);

   /* Timer frequency configuration at 12 MHz */

    PrescalerValue_RPM = (uint16_t) (SystemCoreClock  / 12000000) - 1;

    

  /* Time base configuration */

  TIM_TimeBaseStructure.TIM_Period = 65535;

  TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue_RPM;

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM16, &TIM_TimeBaseStructure);

  TIM_TimeBaseInit(TIM17, &TIM_TimeBaseStructure);

  /* Select the Master Slave Mode */

  TIM_SelectMasterSlaveMode(TIM16, TIM_MasterSlaveMode_Enable);

  /* Master Mode selection */

  TIM_SelectOutputTrigger(TIM16, TIM_TRGOSource_Update);

  /* Slave Mode selection: TIM17 */

  TIM_SelectSlaveMode(TIM17, TIM_SlaveMode_Gated);

  TIM_SelectInputTrigger(TIM17, TIM_TS_ITR1);

  /* Select the Master Slave Mode */

  TIM_SelectMasterSlaveMode(TIM17, TIM_MasterSlaveMode_Enable);

  /* Master Mode selection: TIM17 */

  TIM_SelectOutputTrigger(TIM17, TIM_TRGOSource_Update);

 

  /* TIM enable counter */

  TIM_Cmd(TIM17, ENABLE);

  TIM_Cmd(TIM16, ENABLE);

    

    return 0;

}

The function that return the counter value at 32-bit is:

uint32_t GetCounter32Bit ( void )

{

    uint16_t a, b, c, d;

    /* Reading twice to avoid overflow in the middle of reading */

    a = TIM16->CNT;

    b = TIM17->CNT;

    c = TIM16->CNT;

    d = TIM17->CNT;

    if((a != c) || (b != d))

        return ((uint32_t)c << 16) | d;

    else

        return ((uint32_t)a << 16) | b;

}    

I

hope this is

clear

!