Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!pyramid!athertn!paul
From: paul@athertn.Atherton.COM (Paul Sander)
Newsgroups: comp.sys.apple
Subject: Re: Lower case keyboard (was - :Re: How do you do DVORAK?)
Summary: Not a easy as it looks
Message-ID: <3770@athertn.Atherton.COM>
Date: 23 May 89 03:04:49 GMT
References: <8905150650.AA03263@crash.cts.com> <1975@ur-cc.UUCP> <621@greens.UUCP> <5773@microsoft.UUCP>
Organization: Atherton Technology, Sunnyvale, CA
Lines: 52

In article <5773@microsoft.UUCP>, brianw@microsoft.UUCP (Brian Willoughby) writes:
> In article <621@greens.UUCP> matthew@sunpix.UUCP ( Sun Visualization Products) writes:
> I assume that you had the older keyboard for the Apple II Plus? I made a
> modification to a friend's II Plus which added Lower Case by only adding
> a DPDT switch. On the newer (relatively) II Plus units, the keyboard
> actually had a dotted outline (screen printed on the circuit board) of a
> DPDT switch which could be soldered directly to the keyboard pcboard.
> Then, by cutting two bow-tie options, and solder-bridging two additional
> normally open options, the Apple supplied keyboard generated Lower Case
> and used the added DPDT switch as a caps lock key. I was hard to find a
> right angle PC mount DPDT switch to fit, however. I made this mod after
> adding a new Video ROM to his Plus which allowed lower case characters on
> the Text screen.

So THAT's what that stuff is for...  Neat trick.

> Being a late-comer to the II Plus world, I've always wondered why the
> famed "shift-key mod" was so universally popular, when this mod adds
> lower case without running special code to check the state of Button 3.

The reason for this was because the pre-Rev 7 keyboards had a keyboard
encoder that could not generate lower-case (and many other) characters.
The shift-key mod was a relatively easy patch that most hackers of the
day could manage, and it was widely supported.  Before 1980, this was
the only way of getting lower-case characters without replacing the
keyboard or buying or building a peripheral card of some sort that could
get the characters in.

> The drawbacks of this are:
> 1) You might not have this version of the keyboard.
> 2) There are still some awkwardly placed characters (i.e. M & [)
> 3) You probably will want to modify the Monitor ROM so that it doesn't
> 	convert all lower case characters to upper (this can be 
> 	accomplished by burning a new 2716 with only one byte changed.
> 	The "AND #$DF" in the GETLIN routine must be changed to
> 	"AND #$FF" to defeat the up-shift). Any program which directly
> 	reads the keyboard will work without the custom Monitor ROM.

A problem with this third point is that 2716s do not fit the Apple ][
Plus' ROM sockets.  (Well, they physically fit, but Apple's pinout is
non-standard.)  In order to pull this off, you need to build a special
jig that maps the signals properly.  There is the additional problem that
the location of the ROMs makes such a jig interfere with any expansion cards
plugged into slots 0 and 1 (which are usually filled).  The old ROM cards
(remember when Applesoft could be bought in ROM on a plug-in card?) could
be configured to work with 2716s, and those who still own them could
duplicate their ROMs with this patch, but Apple might take exception to
that.
-- 
Paul Sander        (408) 734-9822       | Do YOU get nervous when a
paul@Atherton.COM                       | sys{op,adm,prg,engr} says
{decwrl,sun,hplabs!hpda}!athertn!paul   | "oops..." ?