[ntp:questions] Using mode byte for Accord GPS Clock (venu gopal)

venu gopal neo.venu at gmail.com
Wed Dec 5 12:46:53 UTC 2007


Hi all,

I need comments from folks who have been maintining reference clk
drivers reg. using extra bits of the mode field to accomodate support
for Accord GPS Clock. Please see the pervious posting on the same
topic.

As Dave Sir has suggested we need to have some agreement reg. this so
that I can proceed to sumbit the modified NMEA driver for approval.

Venu

On 12/5/07, venu gopal <neo.venu at gmail.com> wrote:
> Hi all,
>
> After going through the NMEA ref.clock driver, it seems that the
> original author has choosen values 0(GPXXX), 1(GPRMC), 2(GPGGA) and
> 4(GPGLL) for mode field so that multiple sentences can be selected. As
> posted earlier reg. using the mode byte/field to support Accord GPS
> Clock, fourth bit cannot be used to denote the baudrate.
>
> Fourth bit can denote GPZDG(8) (custom NMEA format) while the fifth
> bit can be used for baudrate 0(4800) and 1(9600). But in this case
> multiple sentences may be allowed only if the value of last four bits
> is less than 8, because GPZDG gives GPS time and not UTC like rest of
> them. So if GPZDG is selected, others sentences should not be
> selected.
>
> Venu
>



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