[Xastir] Re:Xastir and GPS

[Curt Mills, WE7U]

On Tue, 18 Mar 2003, J. Lance Cotton wrote:

> I concur; it seems like option 2 most closely emulates what happens with an
> AUX_TNC interface. In a KPC3+ or similar, the aux GPS port writes data whose
> identity string (first few characters) matches what is desired. Each new NMEA
> sentence from the GPS overwrites what was in the LT buffer before it.
>
> We should think about expiring data in the circular queue also. If there is no
>   data coming in from the GPS, the circular queue doesn't get updated, so it
> looks like there is still valid position data which could possible look 'new'.

Thought about it some more:  figured that we didn't need to go to
all that trouble!

I created two global variables, store GPRMC strings in one, GPGGA
strings in the other.  They get overwritten as each type comes in.

At the check interval, we process the latest strings if they aren't
empty, and then zero the strings.

It works very much like the AUX port GPS stuff in the TNC's does.

-- 
Curt Mills, WE7U                    hacker_NO_SPAM_ at tc.fluke.com
Senior Methods Engineer/SysAdmin
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