Dual serial port modes
- I'm working on getting the second serial port up and running, and I've hit
the first snag - I missed it before, but the second port doesn't have
programmable TX polarity, so if it's going to send data to any normal RS-232
device it's going to need an external inverter.
For the moment, it's hard-coded at 4800 baud and goes only to the NMEA
parser. Without TX capability, it can't speak Garmin - no way to poll the
device and start PVT output.
There will also be some limitations imposed by the simplistic multi-tasking
model used by the tracker. Depending on what you wanted both ports to be
doing, there might be timing limitations. For example, processing a Garmin
position/velocity/time packet takes a relatively long time because of the
math required. If the other port was running a console, you'd probably see
it pause very briefly every second or two when a new position was received.
A dedicated NMEA input seems like the simplest and most common dual-port
configuration. I can see adding an option to disabled Garmin input when
it's in use - I use a Deluo GPS mounted in my car for normal tracking, but
I'll plug in my GPSmap 60cs when I want to see waypoints. If the Deluo was
always used for determining the tracker's position, there'd be no need to
switch cables around.
What I need to know from everyone is what dual-port configurations are
important to you, and I'll try to support what I can. Completely
symmetrical multi-port operation will probably have to wait for my next
NMEA + KISS should be a common one. Seems to work fine so far.
- On Jul 8, 2006, at 11:52 PM, <scott@...>
> What I need to know from everyone is what dual-port configurations areWell, Garmin + KISS (or Garmin + "monitor" mode) would be nice - plot
> important to you, and I'll try to support what I can. Completely
> symmetrical multi-port operation will probably have to wait for my
> project, though.
> NMEA + KISS should be a common one. Seems to work fine so far.
stuff on the GPS and feed an APRS app on a laptop at the same time.
I _really_ like the results of Garmin mode display on the GPS.
- On Sun, 9 Jul 2006, Jason Winningham wrote:
> > NMEA + KISS should be a common one. Seems to work fine so far.Garmin + KISS, or NMEA in/out + KISS are what I'd be interested in.
> Well, Garmin + KISS (or Garmin + "monitor" mode) would be nice - plot
> stuff on the GPS and feed an APRS app on a laptop at the same time.
> I _really_ like the results of Garmin mode display on the GPS.
If the KISS TNC could send the NMEA strings through to the PC, so
much the better. Perhaps as a different device number on an MKISS
Also: Same as above but replace "KISS" with "CMD mode TNC". in
this mode, control-E from the PC should cause the TNC to send the
NMEA string(s) to the PC.
Curt, WE7U. APRS Client Comparisons: http://www.eskimo.com/~archer
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