STM32F103Z Timer Problem

[samed]

Posted on November 18, 2013 at 17:43

I have a Timer Problem . I want that my timer every 1ms makes an interrupt .

I testes it here if (TIM2_Tick >= 1000) but my LED was alway on then I tryied if (TIM2_Tick >= 1000000) and it was about 1 sec (30 blinks in 34 sec) My system_clk is 72Mhz . where is my mistake void Config_Timer(TIM_TimeBaseInitTypeDef *TIM_TimeBaseStructure, NVIC_InitTypeDef *NVIC_InitStructure) {   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);       /* Enable the Timer2 Interrupt */   NVIC_InitStructure->NVIC_IRQChannel = TIM2_IRQn;                          //  configure the Timer2 interrupts   NVIC_InitStructure->NVIC_IRQChannelPreemptionPriority = 0;   //  sets the priority group of the TIMER2 interrupts   NVIC_InitStructure->NVIC_IRQChannelSubPriority = 1;                    //  set the subpriority inside the group   NVIC_InitStructure->NVIC_IRQChannelCmd = ENABLE;                            //  TIMER2 interrupts are globally enabled   NVIC_Init(NVIC_InitStructure);                  /* Configure Timer which is every 1 ms active*/   TIM_DeInit(TIM2);   TIM_TimeBaseStructInit(TIM_TimeBaseStructure);     /* Time base configuration */   TIM_TimeBaseStructure->TIM_Prescaler = 360 - 1; // 72 MHz / 360 = 200 khz   TIM_TimeBaseStructure->TIM_Period = 200 - 1;    // (1/200khz) * 200 = 1 ms;   TIM_TimeBaseStructure->TIM_ClockDivision = 0;   TIM_TimeBaseStructure->TIM_CounterMode = TIM_CounterMode_Up;   TIM_TimeBaseInit(TIM2, TIM_TimeBaseStructure);               /* Enable TIM2 Update Interrupt */   TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);     /* Enable TIM2 */   TIM_Cmd(TIM2,ENABLE);           } void TIM2_IRQHandler(void) {     static int TIM2_Tick = 0;              TIM2_Tick++;         if (TIM2_Tick >= 1000) // 1 Second                 {                     if(check == 0)                     {                         STM_EVAL_LEDOn(LED1);                         check=1;                     }                     else                     {                         STM_EVAL_LEDOff(LED1);                         check =0;                     }                                          TIM2_Tick = 0;         } } I set check=0 in my main once

[Tesla DeLorean]

Posted on November 18, 2013 at 18:00

You don't clear the interrupt, the routine will keep re-entering.

[samed]

Posted on November 19, 2013 at 11:06

You mean

TIM_ClearITPendingBit

(

TIM2

,

TIM_IT_Update

)

;

in my TIM2_IRQHandler ? I put it inside and now the LED is blinking  by the condition if (TIM2_Tick >= 1000) frequent but not like a second . More about 10 times in 19 sec

[Tesla DeLorean]

Posted on November 19, 2013 at 13:33

I put it inside and now the LED is blinking  by the condition if (TIM2_Tick >= 1000) frequent but not like a second. More about 10 times in 19 sec.

But you understand that if you toggle a pin you effectively half the frequency, right?

[samed]

Posted on November 19, 2013 at 14:32

mhh not really maybe you can tell me my mistake.

I thought that every 1ms  my TIM2_IRQHandler is called. Right ? Because of the if if (TIM2_Tick >= 1000) it enters only in when my tick is over 1000. right ? I thought when I toogle my LED It will not take about 0,5 s right ?

[Tesla DeLorean]

Posted on November 19, 2013 at 15:52

For a PERIOD of 1000 ms, the duty for the HIGH and LOW will be 500 ms each, NOT 1000