I've checked in a fix that makes the time-stamping more reliable (but also more "conservative" -> in case there are problems the entire queue is flushed). Please update from svn (http://code.google.com/p/tinyos-main/source/checkout) and retry.
Thanks, Jan On Thu, Nov 18, 2010 at 10:46 AM, Jan Hauer <[email protected]> wrote: > 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 <[email protected]> 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 >> [email protected] >> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >> > _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
