[aprssig] Kenwood/Garmin adapter update

[Derek Koonce]

Nice PCB Scott. For programming, there are sockets that can take the IC 
package and allow you to program off the PCB. If you need me to hunt for 
one I can probably pull a few strings for you; let me know the package 
specs. That would eliminate some of the soldering.

Is this basically a USB to RS232 adapter without the PC? This is a great 
idea and could be used in many other applications. I've been thinking 
about how to put one together but I am an analog / power electronics 
designer and not a digital person.

Derek Koonce
KE6JTP



Scott Miller wrote:
> I've got the first couple of prototypes of my Garmin <> NMEA converter 
> board build and running - beta testing will be starting soon.  This 
> board is intended to work with the nuvi and StreetPilot models that have 
> a mini-B USB connector (and support fleet management mode.)  Here's a 
> picture of my TH-D7A hooked up to a nuvi 350:
>
> http://n1vg.net/images/nuvi_d7.jpg
>
> So far only the nuvi 350 works right for waypoint display, but I think 
> Garmin's going to have a solution for that soon.  Here's another shot of 
> the converter circuit, this one with a DB9:
>
> http://n1vg.net/images/nmea_converter.jpg
>
> It'll probably get overmolded directly into the cable eventually, but 
> for now it's just encapsulated in adhesive-lined heat shrink tubing. 
> Here's the PCB itself:
>
> http://n1vg.net/images/nmea_pcb.jpg
>
> Afraid I only had my phone camera handy when I took that, so the quality 
> is bad.  The whole thing is about 2mm thick.  I probably could have made 
> it a little narrower, but I got tired of playing with the routing.  It's 
> got a 20 MHz HCS08 processor on it, a clock crystal, ESD protection, and 
> an RS-232 transceiver.  It's all powered by the nuvi (but not when the 
> nuvi is on battery power).
>
> I've only got a few prototypes, and I've already got beta testers lined 
> up.  I'm afraid I can't build any more until I get more USB cables 
> (they're non-standard 5-conductor cables with a custom right angle 
> overmold, and the factory is just getting started on them) and soldering 
> a 7mm, 48-contact QFN chip by hand is exceedingly tedious.  I also 
> haven't built a programming fixture yet, so loading the firmware 
> requires soldering wires to test pads and then removing them again when 
> it's done.
>
> But it works!  Plug it in to the nuvi and it starts spitting out GPGGA 
> and GPRMC sentences.  It'll take GPWPL and PKWDWPL (D710) waypoint 
> inputs, and in the case of the PKWDWPL format it'll pick an appropriate 
> symbol as well.
>
> I'm planning on a retail price of $48 for the converter cable.  I'll let 
> everyone know when it's available.
>
> Scott
> N1VG
>
>
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