trigger timer before periode expiration

Kernel
1

po220 wrote on Friday, November 11, 2016:

Hi

I’m using a periodic timer

Timer1 = xTimerCreate(“Timer1”, 10000, pdTRUE, (void *)0, Timer1Callback) ;
xTimerStart(Timer1, 0) ;

How can I force the timer to expire immediately ?

15:10 pm => Timer1 start
15:20 pm => Timer1 should execute the callback function

and me, at 15;12 pm, I need to execute the callback function, with(top solution) or whithout reset of the timer.

I do not see any solution here
http://www.freertos.org/FreeRTOS-Software-Timer-API-Functions.html

Thanks in advance

2

rtel wrote on Friday, November 11, 2016:

If you don’t want to reset the timer, just call the timer callback
function as any other function. Otherwise you would have to stop the
timer then restart it with a new timeout time (or just change its period
so it expires at the new desired time, which effectively does the same
thing).

3

po220 wrote on Friday, November 11, 2016:

Thank for your answer

What happens by calling the callback directly?
Timer1Callback(Timer1) ;

The timer don’t restarts for a complete new period.

No risk of disrupting timer normal operation ? or I need make a
xTimerReset( Timer1,0); just before the Timer1Callback(Timer1) ?

thanks

4

rtel wrote on Friday, November 11, 2016:

Timer callback functions are just standard C functions, and can be
called by another task (in which case the function runs in the context
of the calling task). As all you are doing is calling a C function it
will not change the software timer, which will continue and expire just
as it would have done otherwise.

5

po220 wrote on Friday, November 11, 2016:

Ok

xTimerReset( Timer1,0);
Timer1Callback(Timer1) ;

Is therefore a good solution ?
How to prevent the callback function from calling 2 times ? Semaphore ?

Thanks

6

davedoors wrote on Friday, November 11, 2016:

Im confused. What are you trying to do?

15:10 pm => Timer1 start
15:20 pm => Timer1 should execute the callback function
and me, at 15;12 pm, I need to execute the callback function, with(top solution) or whithout reset of the timer.

So you thought the timer should expire at 15:20, but something happened that means it now needs to expire at 15:12. Do you want it to execute at 15:20 as well? If so just call the callback function at 15:12 from a task. If you dont want it to execute at 15:20 as well just stop the time then call the callback from a atsk.

7

po220 wrote on Friday, November 11, 2016:

I need

15:10 => timer execute callback function
15:12 => execute callback function “manualy”
15:22 =>timer execute callback function
15:32 =>timer execute callback function
…

8

po220 wrote on Friday, November 11, 2016:

My solution, if you confirm.

xTimerReset(Timer1,0);

while(xTaskGetHandle("Tache1") != NULL) vTaskDelay(10) ; //Wait for callback function end.

Timer1Callback(Timer1) ;

the callback fonction create the “Tache1” task.

It’s OK for you ?

Thanks

9

rtel wrote on Friday, November 11, 2016:

You could perform the reset of the timer from the timer callback
function itself. That way if you manually execute the callback function
the timer will automatically reset at that point.