Loading ...
Sorry, an error occurred while loading the content.
 

Dual serial port modes

Expand Messages
  • scott@opentrac.org
    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
    Message 1 of 3 , Jul 8, 2006
      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
      project, though.

      NMEA + KISS should be a common one. Seems to work fine so far.

      Scott
    • Jason Winningham
      On Jul 8, 2006, at 11:52 PM, ... Well, Garmin + KISS (or Garmin + monitor mode) would be nice - plot stuff on the GPS and feed an APRS
      Message 2 of 3 , Jul 9, 2006
        On Jul 8, 2006, at 11:52 PM, <scott@...>
        <scott@...> wrote:

        > 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
        > project, though.
        >
        > NMEA + KISS should be a common one. Seems to work fine so far.

        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.

        -Jason
        kg4wsv
      • Curt, WE7U
        ... Garmin + KISS, or NMEA in/out + KISS are what I d be interested in. If the KISS TNC could send the NMEA strings through to the PC, so much the better.
        Message 3 of 3 , Jul 10, 2006
          On Sun, 9 Jul 2006, Jason Winningham wrote:

          > > NMEA + KISS should be a common one. Seems to work fine so far.
          >
          > 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.

          Garmin + KISS, or NMEA in/out + KISS are what I'd be interested in.
          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
          interface?

          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
          "Lotto: A tax on people who are bad at math." -- unknown
          "Windows: Microsoft's tax on computer illiterates." -- WE7U
          "The world DOES revolve around me: I picked the coordinate system!"
        Your message has been successfully submitted and would be delivered to recipients shortly.