No accessible timer state?

Ingolf Steinbach ingolf.steinbach at
Tue Mar 30 15:11:16 UTC 2010

2010/3/30 Joel Sherrill <joel.sherrill at>:
> The rtems_timer_get_information() call does most of this.
> Is it what you want?

Thanks, Joel, that is good news.

>     the_info->the_class  = the_timer->the_class;
>      the_info->initial    = the_timer->Ticker.initial;
>      the_info->start_time = the_timer->Ticker.start_time;
>      the_info->stop_time  = the_timer->Ticker.stop_time;

For the layman (with respect to RTEMS internals), it is not clear how
these elements are to be interpreted. For instance, in which time
scale are "start_time" and "stop_time"? What does "initial" mean?

*Experiments* indicate that "initial" is the duration (in ticks), and
that initially, stop_time = start_time + initial.

At the time of invocation of the TSR, stop_time seems to be 0 -- most
of the time(!) -- so this probably can be used to determine whether
the timer is still running.

However, we have noticed that for the very first invocation of the
TSR, stop_time is non-zero (at least with 4.6.x).

> Please submit a patch for the documentation.

See above, there are several issues which would have to be clarified in advance.

Kind regards

PS: The original question was not intended to be criticism. It had
really not been clear to me whether the documentation had been left
out on purpose or just forgotten.

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