Re: TI-H: RF link
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Re: TI-H: RF link
On Mon, 23 Oct 2000 14:53:03 -0500 Bryan Fields <kb9mci@qsl.net> writes:
>
> > Emulating a direct link-cable connection would be best i think in
> that
> > hardly any software would need to be written (can be done in basic
> if needed
> > too) and it would be compatible with 'all' (prove me wrong) TI
> calcs.
>
> emulating the link cable might be the best thing, but i cannot say
> b/c i
> do not know much about it. does any one have any info on the
> protocol
> that the port uses?
the standard protocol requires 2 level transitions from each side per
bit.
both lines are normally high (+6v or so)
to transmit one bit, the sender drives one line low, then the recieving
end drives the other low. the sender then allows its line to float high
again and the rx responds by floating the other line.
1 and 0 are distinguished by which line the sender drives low.
i recommend transmitting line levels / transitions if you don't want to
use a better protocol than this one.
> > PS. The radio link cable that ive see on the net so far is quite
> complicated
> > and uses IC's that ive never seen before.
>
> CAN SOME ONE POST A URL TO THIS????? i would like to see it b/f
> designing something else. a goo engineer try's to accomplish a give
> task with as few original ideas as possible.
www.fission2.com/html/radiolinc.htm used to have schematics that were
almost copied directly out of an appnote for a 433 MHz radio transciever
chip.(nRF0433; datasheet: http://www.elfa.se/pdf/73/730/07300288.pdf)
this was posted as a news item to ticalc.org, but the site no longer
exists. it's fairly likely that they didn't quite know what they were up
against. (no news since february)
-josh
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