[Tinyos-help] CC2420Config.syncDone() may not get called after sync() return SUCCESS

[Tie Luo]

Embedded below.

On 10/26/06, Philip Levis <pal at cs.stanford.edu> wrote:

> On Oct 25, 2006, at 9:32 AM, Tie Luo wrote:
>
> > If radio is busy, I think CC2420Config.sync will fail, or may
> > return SUCCESS and signal syncDone at some time later. I do not
> > understand what you said "if sync were to never signal done, then
> > it is unlikely that the radio is receiving/transmitting packets."
> > Did you mean if syncDone is not signalled, then radio is likely to
> > be free?  I am confused since free radio should be easier for
> > switching channels.
>
> I mean that if syncDone never signals, then it is unlikely that the
> other parts of the radio are able to access the bus. If they can't
> access the bus, then it is unlikely that the stack can send/receive
> packets.


I would agree.  Because in my experiment, after switching channels back and
forth many times (and some collisions may happen on some channels), some
motes fail to send messages.  I have spent much time to fix this problem but
not yet until now. :-(

I am suspecting syncDone() never gets signaled, even if sync() return
SUCCESS.  That's why I previously ask if there is a bug to be fixed in
tinyos.



> >
> > For the tests you mentioned before, I found some channels can be
> > switched to while some cannot. But I had not run thorough tests on
> > all channels.
> >
>
> Can you name one which cannot?



20



> >
> > The bug that I mentioned, and has been fixed by Tinyos team, is in
> > CC2420ControlP.nc line 273, SyncResource.release() is added.
> >
> OK.
>
>
> > Answering your last question, I am not using SPI for other things
> > like large storage op; what I am doing is purely radio
> > communications and computations.
> OK. If you were using the bus for other operations, then this might
> cause syncDone to be delayed for a long time.
>
> Phil
>



-- 
Regards,
Tie
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