Hi, NMEA would have been nice - but this is a timing application.
Stephan. 2008/11/19 Stanley Reynolds <[EMAIL PROTECTED]> > Looking at the user guide which is the extent of my experience. Would the > position version of the M12+ be a better choice for your application ? That > is trade NMEA-0183 for all the timing features ? > > Stanley > > Link to user guide : > http://www.synergy-gps.com/images/stories/guides/m12+userguide.pdf > > > > > > > ________________________________ > From: Stephan Sandenbergh <[EMAIL PROTECTED]> > To: Discussion of precise time and frequency measurement < > time-nuts@febo.com> > Sent: Wednesday, November 19, 2008 8:29:59 AM > Subject: [time-nuts] M12+T ASCII interface - I'm confused? > > Hi All, > > Up until now we've been interfacing my Motorola M12+T's using the Oncore > software. However, at this point we are trying to have it interfaced > directly to a FPGA. To my mind this should be simple - the commands are > discriminated (framed) by looking at the start and terminating bytes > sequences when they enter the FIFO, check summed, decoded etc. > > However, I noted something very peculiar about the motorola ASCII protocol: > The start bytes @@ and he terminating byte <CR><LF> aren't unique with > respect to the data bytes. For instance one could receive a time of 13hrs > and 10mins which would look identical to the terminating characters. > Initially I thought it made sense since the data is also sent in ascii > format. It appears not to be the case. > > It seems to me that the only way in which a command could be robustly > identified and check summed is when the interface knows the length of the > expected return. Obviously, the data lengths are dependent on both the > actual command and the specific request. This type of intelligence is > cumbersome to implement in FPGAs. > > It would be of great help if you could point me in the right direction > here. > I feel rather stupid in asking such a simple question, but at this point I > can't seem to see the light. I'm flabbergasted... > > Best regards, > > Stephan > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.