hi carlos,
the reason why FTSP does not support T32khz is that there is currently
no HIL component providing T32khz time. however, the timestamping code
on cc2420 platforms supports T32khz. in particular, TimeSyncMessageC.nc
provides interfaces with both TMilli and T32khz precision.
thus i'd suggest you to modify tos/lib/ftsp/TimeSyncC.nc and change
Milli for 32khz in the following 3 lines
...
provides interface GlobalTime<TMilli>;
...
components new TimeSyncP(TMilli);
...
TimeSyncP.Send -> ActiveMessageC.TimeSyncAMSendMilli[AM_TIMESYNCMSG];
...
then you need to provide T32khz LocalTime to TimeSyncP, however,
HilTimerT32khzC does not exist. you need to work around this using
Counter32khz32C and CounterToLocalTimeC, as in
tos/chips/cc2420/CC2420TimeSyncMessageC.nc
btw. T32khz will not give you microsec precision - a jiffy is ~30us.
brano
Carlos Gil Soriano wrote:
> Hi Marco,
>
> thanks for your prompt response.
> I mean, what I want to do as a first step is to verify that setting up
> FTSP with a microsecond scale is feasible. In order to do this, I have
> tried to modify TestFtsp with no success.
> Is it possible to modify TestFtsp so as to get microsecond precision?
>
> Yours,
> Carlos
>
> 2009/2/24 Marco Antonio Lopez Trinidad <[email protected]
> <mailto:[email protected]>>
>
> There is may be a natural precision overflow problem, whether you
> try to change
> from a usec to a msec timing with a unique timer.
>
> The solution can be that your program must drive two timers, one
> that performs
> at usec and the second at msec speed. Your program must check
> whether the first
> or the second timer must be used.
>
> ciao,
> --marco.
>
> > Hi Marco,
> >
> > I've tried with the 32 Khz Alarm, the problem is that when
> changing the
> > precision tag to 32khz instead of TMilli of the timers, I got
> compilation
> > problems. Then, checking TimeSyncC I see that GlobalTime timer ( i
> > understand that is the basic interface of FTSP) is defined with a
> fixed
> > precision of TMilli.
> > So, what I mean is if there is possible to easily change the
> precision of
> > the timers and, if it is possible, what precision tags could be
> used?.
> >
> > Regards,
> > Carlos
> >
> >
> > 2009/2/24 Marco Antonio Lopez Trinidad <[email protected]
> <mailto:[email protected]>>
> >
> > > Why do you not try with a 32 kHz alarm?
> > >
> > > --marco.
> > >
> > > > Hi,
> > > >
> > > > I'm evaluating the precision of FTSP on micaz platform. As the
> > > publications
> > > > says, the absolute error should be around a couple of
> microseconds.
> > > > First thing I've tried was the TestFtsp program. It works
> fine but I want
> > > to
> > > > check the limit of precision of FTSP and, because TestFtsp is
> based on
> > > > timers with milliseconds precision, I decided to change them
> for 32Khz
> > > > timers. However, several errors appeared and while checking
> through
> > > > TimeSyncC I've found that changing the precision of the
> timers is not a
> > > > straightforward task.
> > > > Has anybody tried to change the precision of the timers to
> 32Khz instead
> > > of
> > > > the default 1ms (TMilli)?
> > > >
> > > > Any help would be appreciated.
> > > >
> > > > Thanks,
> > > > Carlos
> > > >
> > >
> > >
> > >
> > >
> >
>
>
>
>
>
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