• State Not Answered
  • Locked Locked
  • Replies 5 replies
  • Subscribers 20 subscribers
  • Views 14280 views
  • Users 0 members are here
Options
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

STM32 timer does not work like expected

Norbert Seng

Hello,

It's my first project with STM32 and ST firmware library.
I have a problem with my timer configuration. I want a cyclic timer 2 interrupt all 100 us (10 kHz). So I configured the timer:

  TIM_TimeBaseStructInit( &TIM_TimeBaseStructure );
  TIM_TimeBaseStructure.TIM_Period = 100;
  TIM_TimeBaseStructure.TIM_Prescaler = 35;
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure );
  TIM_ITConfig( TIM2, TIM_IT_Update, ENABLE );
  TIM_Cmd( TIM2, ENABLE );


Notes:
TIM2CLK is 36 MHz.
Prescaler = 35 ==> TIM2 counter clock = 1 MHz
- because TIM2 counter clock = TIM2CLK / (Prescaler +1)
Auto reload preload value: 1 MHz / 10 kHz = 100

So I expected an timer 2 interrupt all 100 ms. But when my program runs at my ST STM3210B evaluation board or in the simulator, the interrupt comes all 50 us (20 kHz).

What is wrong? - Any idea?

Thanks in advance,
Norbert

0