Aditya, Here's how it works. The nodes running TestFTSP synchronize with the FTSP protocol in the background. When they receive RadioCountToLeds message, they timestamp it with the synchronized global time, and send that timestamp to the PC.
The FTSP protocol does not use the RadioCountToLeds messages in any way. It uses its own message structures and AM id (TIMESYNC_AM_FTSP). These are the messages that are used to establish a synchronization point. The implementation is in tos/lib/ftsp. Janos On Wed, Dec 16, 2009 at 4:53 AM, Aditya Prasad <[email protected]> wrote: > I was introduced to TinyOS and nesC a few months back and currently > I'm working on time synchronization of TelosB motes. In this regard, > I've been trying to understand the implementation of FTSP via the > TestFTSP application. Being a beginner, I am facing a few hiccups and > would be really glad if you could answer some of my queries. > > 1) As I understand, RadioCountToLeds sends a sequence number to > TestFTSP which then captures the received time stamp using the > PacketTimeStamp interface. Since the FTSP algorithm requires a > synchronization point to consist of an RX time stamp, TX time stamp > pair, how are you retrieving the time at which radioCountToLeds sent > the sequence number (i.e., TX time)? RadioCountToLeds is the reference > node providing the global time to which all nodes would synchronize, > am I right? > > 2) There is a receive event in TestFtspC.nc which receives the packets > sent by RadioCountToLeds > App.Receive->ActiveMessageC.Receive[AM_RADIO_COUNT_MSG]). I would like > to know what > triggers the receive event in TimeSyncP.nc (TimeSyncP.Receive > ->ActiveMessageC.Receive[TIMESYNC_AM_FTSP]) ? > What is the purpose of the 2 AM types - TIMESYNC_AM_FTSP and AM_TEST_FTSP_MSG? > > Regards, > Aditya > _______________________________________________ > 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
