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 <[email protected]> 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 -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
