[aprssig] D700/D710 to Garmin adapter

[Scott Miller]

Just wanted to give a quick update on a project I mentioned at Dayton. 
I've built a protocol translator (largely based on code from the T2) 
that converts Garmin asynchronous binary protocol (including FMI data 
from the newer nuvi and StreetPilot units) to NMEA (GPGGA, GPRMC, and 
GPGLL), and also functions in reverse to create waypoints from GPWPL and 
PKWDWPL (D710) sentences.

For the D710, it does symbol translation (picking the closest available 
Garmin native symbol), and includes the course/speed and altitude data 
in the comment details.  Waypoint display works on just about any of the 
serial interface units (chartplotters, GPSmap handhelds, serial eTrex, 
etc), but so far of the nuvi/StreetPilot series, only the nuvi 350 works 
right.  The rest will output position data, but not display waypoints.

Anyway, the point is that there'll be an alternative to the $700 AvMap 
displays.  Hopefully Garmin will come through with some fixes for the 
other models soon.

For what it's worth, I've also added experimental support for the AvMap 
to the Tracker2.  There doesn't seem to be much interest when it works 
natively with the Garmins, though.

Next up, I get to squeeze this whole thing into a little tiny connector 
shell.  Looks like I'll get to try my hand at soldering 7mm QFN48's...

Scott
N1VG