Timer interrupt works immediately

[David Martins]

Posted on June 21, 2016 at 10:52

Hello.

I have configured the timer 6 to interrupt every 3s, but immediately after initialize the timer the interrupt occurs.

Why?

1 - HAL_TIM_Base_Init (&htim6);

2 - HAL_TIM_Base_Start_IT(&htim6);

3 - ''immediately'' (almost) it goes to interrupt handler...

How can I resolve this problem?

Thank you.

[waclawek.jan]

Posted on June 21, 2016 at 11:57

> Why?

Because

> 1 - HAL_TIM_Base_Init (&htim6);

forces update through setting TIMx_EGR.UG (the reason is to force the prescaler setting into the real prescaler counter).

> How can I resolve this problem?

Clear TIMx_SR.UIF before enabling the timer.

JW

[David Martins]

Posted on June 21, 2016 at 12:32

Hello.

I had already done it ... but the result is the same.

The interruption is immediate ...

https://s31.postimg.org/bgurb25a3/Capturar.png

[waclawek.jan]

Posted on June 21, 2016 at 12:45

Clear the flag *before* HAL_TIM_Base_Start_IT().

JW

[David Martins]

Posted on June 21, 2016 at 13:00

Oh... sorry xD.

I think that the flag had changed in Start_IT, so I tried modify the flag after...

In resume, the flag is changed in Timer Init...

My mistake.

It works!

Thank you very much!