[ntp:questions] Using mode byte for Accord GPS Clock

venu gopal neo.venu at gmail.com
Tue Dec 4 11:01:55 UTC 2007


    Hi all,

        The 'mode' field a.k.a 'ttl' for NMEA reference driver is used
to select the NMEA
    sentence. I cannot use the unused fudge flags 'flag1' and 'flag4'
as they are unavailable
    before the serial port is opened. Somehow I have to select both
the baudrate and the
    NMEA sentence from the 'mode' field itself.

    Currently 'mode' field with values 0,1,2,4 are used in NMEA
reference driver with default
    baudrate of 4800. Can I use the 'mode' field with value 8 and the
rest of the three bits to
    select NMEA sentence.

        1. Mode value 8  => 9600, GPXXX
        2. Mode value 9  => 9600, GPRMC
        3. Mode value 10 => 9600, GPGGA
        4. Mode value 11  => 9600, GPGLL
        5. Mode value 12 => 9600, GPZDG (Accord custom NMEA sentence)
        6. Mode value 13 => 9600, GPZDA

    So the 4th bit of the 'mode' field is used to check if baudrate
needs to be changed,
    while the rest of the 3 bits denote the NMEA sentence to be selected.

   Comments plz...

    Venu.



More information about the questions mailing list