[Tinyos-help] Bug in CC2420 timestamp

[David Moss]

I haven't done much work with the timestamps in the CC2420 apart from
Jonathan's original implementation, nor have I used it enough to have
experienced any type of erratic behavior.  Is the issue here that the 16-bit
timestamp rolls over to 0 periodically?  Would a 32-bit timestamp be better?

-David


-----Original Message-----
From: tinyos-help-bounces at Millennium.Berkeley.EDU
[mailto:tinyos-help-bounces at Millennium.Berkeley.EDU] On Behalf Of Federico
Fiorentin
Sent: Tuesday, October 30, 2007 6:39 AM
To: tinyos-help at Millennium.Berkeley.EDU
Subject: [Tinyos-help] Bug in CC2420 timestamp

I'm working on time synchronization with tmote sky motes and TinyOS2.

I'm using a poller that sends a PollPacket every X milliseconds and a
set of clients that timestamp the arrival time of the PollPacket.
I found that the 16 timestamp in the time field of the Metadata are
somethimes incorrect ( CC2420Packet.getMetaData(msg)->time ).

This affects the 1% of the TimeStamps per mote.
I compared the value "timestamp(n) - timestamp(n-1)" of two different motes.

Is there any patch or a way to fix it?

I appreciate any advice
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