Re: TI-H: Keyboard

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Re: TI-H: Keyboard


Well, here's the deal.  You have two routes to go:

One:
The TI-89 and 92 have external control ability, ie, you can send keypresses to
the calc, and it will handle them just as if they were typed from the keypad
without any programming whatsoever.  Spiffy, huh?  This requires an external
keyboard interface involving a microcontroller.

Two:
The hardware interface for the graphlink port and the AT type keyboard (ps/2)
are similar, both are open collector outputs/inputs.  Therefore it is possible
to make a cable which hooks the keyboard directly to the graphlink.  The issue
here is that they do not speak the same protocol, and the keyboard does not spit
out ascii characters.  You will need to write a program on the calculator which
will directly control the pins for the graphlink, accept input, run it through a
translation table, and then insert it into the key buffer on calc.

I personally would go for the first routine, as I am more comfortable dealing
with uControllers than I am with programming the calc.  I am certian, however,
that an enterprising DOORS developer could go with number two just as easily as
I woul go with number one.

For information on interfacing to a keyboard (electrical and protocol) see
http://www.beyondlogic.org/
For information on interfacing and programming the TI calculator, see
http://www.ticalc.org/

I do a small amount of consulting.  If you want me do do the work for you for
option one, I would charge $45/hr labor.  I have the materials, and would
estimate about 5 hours from spec to design to test to completion.  This would
include one finished product, embedded into a cable.

One item worth mentioning:  Keyboard manufacturers have never needed to worry
about keeping a low power consumption.  Some keyboards suck 250mA or more, using
a complete set of four AA's in under 6 hours (continuous use).  You are advised
to explore this and other items before embarking on this project.

-Adam

Nivek wrote:
> 
> --- Grant Stockly <gussie@stockly.com> wrote:
> >
> > >hey, what has happend, is this compleat??? can i get one??? where???
> > >thanks.
> >
> > Nothing has happened.  No it isn't complete.  You can't get one.  No
> > where.
> >
> 
> darn, can anybody give me info on how to write the program and what
> kind of converting i would need to do, so that i can do it myself.  for
> TI-89 if possible.
> 
> =====
> Nivek
> Nivek_ent@yahoo.com
> http://come.to/NivekEnterprises
> 
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