[riot-devel] Question about hwtimer_now implementation..

Ludwig Ortmann ludwig.ortmann at fu-berlin.de
Tue Oct 14 19:26:58 CEST 2014


Hi Michael,

On Tue, Oct 14, 2014 at 01:17:44PM -0400, Michael Burg wrote:
> 
> Hello,
> 
> I'm trying to port RIOT to a FRDM-KL46Z board (ARM cortex m0-plus based),
> and having a some trouble understanding how the hardware timer code is
> supposed to be implemented.
> 
> Specially, what should be hwarch_now()/hwtimer_arch_now be returning?
> 
> Is it supposed to be the ticks from boot, or the current value of the timer
> from when hwtimer_arch_set*() called?

hwtimer_arch_now should return the "system time".
As the timer may overflow, this is the tick count since boot in the
first iteration.

In case you didn't notice, there's documentation in core/include/hwtimer.h
which says:

    "The current tick count of the hardware timer"

Did you see this and found it inconclusive?
In that case would try to improve the documentation, so don't hesitate
to "yes" here ;)

Cheers, Ludwig


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