[Tinyos-help] 802.15.4

Aitor Hernandez aitorhh at kth.se
Thu Nov 18 04:48:36 PST 2010


In my case, I just program all the motes at the same time by using "&"
function on the shell, something like:

$ make tmote
$ make tmote reinstall,1 bsl,/dev/ttyUSB1 & make tmote
reinstall,2 bsl,/dev/ttyUSB2

By the way, I've been using the UserButton for some time, and I've never
noticed the behaviour you explain, with or without TKN154_DEBUG enabled.

Best,

Aitor


On 18 November 2010 13:28, Pablo Marcos Oltra
<pablo.marcos.oltra at gmail.com>wrote:

> May I add other option to the Aitor ones?
>
> I thought about letting the motes synchronize first, and then start sending
> packets once they're all synchronized. How could you do this? I have tried
> doing that with the telosb user button, hence once you pressed it you change
> a flag that starts sending packets. The problem is that I have just been
> able to do that with the TKN154_DEBUG enabled, otherwise, the event void
> Notify.notify( button_state_t state ) is not working.
>
> You can see an example of how to use the telosb user button in
> $TOSROOT/apps/tests/telosb.
>
> Regards,
>   Pablo
>
> 2010/11/18 Jan Hauer <hauer at tkn.tu-berlin.de>
>
> yes - I can reproduce the problem and also believe that it is due to
>> wrong (beacon) timestamps. will look into it and try to fix it asap.
>>
>> thanks,
>> jan
>>
>> On Thu, Nov 18, 2010 at 10:02 AM, Aitor Hernandez <aitorhh at kth.se> wrote:
>> > Hi guys,
>> > I've seen this problem with TKN15.4. It is possible to synchronize N
>> nodes
>> > with TKN15.4 the problem is that they need to start the app at the same
>> > time. From my experience I've realized that the problem comes from the
>> > cc2420_tkn154 (maybe it happens with the default cc2420 implementation
>> as
>> > well).
>> > If we have a network with N nodes running and transmitting data between
>> > them, when we try to add another node we could have this problem. As far
>> as
>> > we have the radio enabled for reception for a long period (Scan period),
>> the
>> > cc2420 receives the beacons but data packets as well. Once it detects
>> that
>> > the received packet is a beacon, it sets the timestamp, but sometimes
>> the
>> > timestamp is wrong, due to the data packets, and then we lost the next
>> > beacons.
>> > Possible solutions:
>> >
>> > Check the CC2420ReceiveP.nc and the m_timestamp_queue. I guess that the
>> > problem should be there. I did some modifications on
>> > the CC2420ReceiveP.nc to solve this problem, but I haven't test it
>> properly.
>> > If we lost the synchronization, scan again with MLME_SCAN.request(). It
>> is a
>> > "fake" solution, because the problem is still there, but for some app it
>> > will work.
>> > Start the nodes at the same time. It is not possible in a real
>> deployment.
>> >
>> >
>> > --
>> > Aitor Hernandez
>> > KTH | Automatic Control
>> > Research engineer
>> > Stockholm
>> > Phone:  +46 (0)704 26 87 99
>> >
>> > _______________________________________________
>> > Tinyos-help mailing list
>> > Tinyos-help at millennium.berkeley.edu
>> >
>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
>> >
>>
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>
>


-- 
Aitor Hernandez
KTH | Automatic Control
Research engineer
Stockholm
Phone:  +46 (0)704 26 87 99
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