7 Sep
2007
7 Sep
'07
8:23 a.m.
Paul Heller wrote:
On Sep 5, 2007, at 4:10 PM, Brent Hilpert wrote:
Rick Bensene wrote:
I received two orphan 320K keyboard/display units a few years ago
(no logic unit).
...
Cool idea. Did you find the hardware interface documented somewhere,
or did you reverse engineer it somehow? Was it something standard
like RS-232?
The keyboard/display units were simple -- WAY more simple than serial
RS-232. Logic levels were not TTL (remember, these machines were made
with all-transistor...no IC's anywhere either the keyboard/display
units, nor the electronics package).
...
... everything Rick said. (Yes, it was RE'd.) The level shifters just needed
a few transistors and resistors - logic levels in the Wang are 0V and ?10V.
Another nice thing about the Wang KDUs for this purpose is the key-caps are
composed of snap-on clear plastic tops with a paper label underneath, so it's
easy to print/relabel the entire keyboard to whatever calculator layout you
like, rather than being stuck with either the Wang functions/semantics (which
are a little unusual) or obtuse labels. For my desires, the target user interface
was straightforward RPN style, essentially modeled on my little old HP-21.
(On the other hand, who uses a calulator any longer? For me, anything more
than one or a couple of multiplications or divisions, and it's straight to the
spreadsheet app kept idling in the background.)