[comp.sys.handhelds] Chord Keying on HP 48sx - possible?

gak@apple.com (Greg Kimberly) (05/09/90)

Various postings have mentioned that the keyboard of the 48 is soft 
assignable. Is their a way to assign values (i.e. characters) to 
combinations of keys? If so, then it ought to be possible to make a chord 
keyset mode to ease the entry of text. Does anyone have an idea of whether 
this can be done?

garyf@jpl-devvax.JPL.NASA.GOV (Gary Friedman) (05/10/90)

In article <8136@goofy.Apple.COM> gak@apple.com (Greg Kimberly) writes:
>Various postings have mentioned that the keyboard of the 48 is soft 
>assignable. Is their a way to assign values (i.e. characters) to 
>combinations of keys? If so, then it ought to be possible to make a chord 
>keyset mode to ease the entry of text. Does anyone have an idea of whether 
>this can be done?

I thought of doing this on my HP-71 (What's *that*? :-))  The assembly
language algorithm would be relatively simple: scan the keyboard by
writing to the OUT register and reading corresponding 1's on the IN
register; take note of every key found depressed and wait untill all
buttons are up before translating the keycode and placing the result
into the key buffer.  

The HP-48 has some rather stiff buttons, making chordian typing a
stress-inducing activity.  Power consumption would also skyrocket,
since the CPU would be actively seeking inputs rather than going to
sleep and waiting for an interrupt between keystrokes.

Finally, the amount of work necessary to display the text sideways on
the 48's display (you *were* going to place this thing horizontally,
weren't you?) makes calling the UK and ordering an already-implemented
AgendA seem like a level-headed solution.


							-Garyf


Gary Friedman                 Jet Propulsion Laboratory - NASA
4800 Oak Grove Drive, Pasadena, CA.  91109      (818) 354-0410
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-- 
Gary Friedman                 Jet Propulsion Laboratory - NASA
4800 Oak Grove Drive, Pasadena, CA.  91109      (818) 354-0410
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