On a related subject, can anyone give me an idea of what it would take to accept a stream of NMEA $GPRMC sentences on the Rio/Empeg serial port and display position, velocity and time on the RIO/Empeg. This is ASCII data and requires very little formatting to be useful though some units conversion would be helpful (knots to MPH or KPH).

Take a look at the hijack kernel mods for an easy way to display stuff on the screen. You can basically just cat text to a /dev entry.

In order to use the serial port you need to write a custom init script that starts the player with the appropriate flag to keep it from locking the serial port to output its debug info (I think it is -s but search here).

Reading from the serial port is trivial, you may have to set the speed first though.

As far as parsing the NMEA data, it sounds like you may know what you are doing already. I started to rip some code out of one of the open source gps clients (jeeps I think?) a while back to do this. IIRC I had it working aside from some endianness issues with the long and lat that I didn't know how to get around.

Now that I think about it, now that mlord has done all the UI work with hijack this should be pretty trivial to do.

-Mike