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8755Re: [tracker2] LCD & cable length question

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  • Tanner Lovelace
    Oct 2, 2009
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      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?

      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
      (fieldless) In fess two roundels in pale, a billet fesswise and an
      increscent, all sable.
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