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

Re: [tracker2] LCD & cable length question

Expand Messages
  • Scott Miller
    You can get away with a fairly long radio cable if you can keep RFI out of it. The OT2m has ferrite chips on the radio interface lines, but shielded cable
    Message 1 of 7 , Oct 1, 2009
    • 0 Attachment
      You can get away with a fairly long radio cable if you can keep RFI out
      of it. The OT2m has ferrite chips on the radio interface lines, but
      shielded cable would still be a good idea.

      I think someone already suggested it, but a line driver might help on
      the LCD interface. I think the limiting factor is going to be line
      capacitance vs. signaling speed. Many LCDs will work with 3v inputs, so
      it should tolerate some voltage drop.

      As for the signaling speed... without the disassembled code in front of
      me I'm not sure how many cycles the LCD clock toggle takes, but I don't
      think it can be less than 4, so that'd give it a max clock speed of
      about 1.8 MHz. Adding more NOPs to the ClkPause macro would slow it down.

      Again, you'll have to watch out for RFI on those long low-voltage runs.

      Scott

      Tanner Lovelace wrote:
      >
      >
      > Does anyone have an idea what kind of cable length limitations there are on
      > connecting an LCD to the tracker2? If I put the tracker 2 in my trunk
      > and want
      > to have an LCD in the front of the car will that work?
      >
      > Alternatively, if I place the tracker2 in the front of the vehicle and
      > the radio
      > in the trunk, how long can the cable between the T2 and the radio be?
      >
      > Thanks very much.
      >
      > Cheers,
      > Tanner Lovelace
      > KB4TYE
      >
      > --
      > Tanner Lovelace
      > http://wtl.wayfarer.org/ <http://wtl.wayfarer.org/>
      > (fieldless) In fess two roundels in pale, a billet fesswise and an
      > increscent, all sable.
      >
      >
    • Tanner Lovelace
      Actually, what I decided to do instead was order an LCD and an Arduino and I m going to see if I can get the same type of display up and running with that.
      Message 2 of 7 , Oct 2, 2009
      • 0 Attachment
        Actually, what I decided to do instead was order an LCD and an Arduino
        and I'm going to see if I can get the same type of display up and running
        with that. That will let me use a serial connection from the OT2m to the
        Arduino which shouldn't have any problem with a long run (hopefully!)

        BTW, I've seen several people talk about trying to use an Arduino
        to put together a sort of HamHud interface that would connect to
        the OT2m. What's the latest story on that? What kind of input
        device would you use?

        Cheers,
        Tanner Lovelace

        On Thu, Oct 1, 2009 at 11:48 PM, Scott Miller <scott@...> wrote:
        > You can get away with a fairly long radio cable if you can keep RFI out
        > of it.  The OT2m has ferrite chips on the radio interface lines, but
        > shielded cable would still be a good idea.
        >
        > I think someone already suggested it, but a line driver might help on
        > the LCD interface.  I think the limiting factor is going to be line
        > capacitance vs. signaling speed.  Many LCDs will work with 3v inputs, so
        > it should tolerate some voltage drop.
        >
        > As for the signaling speed... without the disassembled code in front of
        > me I'm not sure how many cycles the LCD clock toggle takes, but I don't
        > think it can be less than 4, so that'd give it a max clock speed of
        > about 1.8 MHz.  Adding more NOPs to the ClkPause macro would slow it down.
        >
        > Again, you'll have to watch out for RFI on those long low-voltage runs.


        --
        Tanner Lovelace
        http://wtl.wayfarer.org/
        (fieldless) In fess two roundels in pale, a billet fesswise and an
        increscent, all sable.
      Your message has been successfully submitted and would be delivered to recipients shortly.