Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!ames!amdahl!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: Monitor ROMs _ARE_ nonstandard
Message-ID: <4251@athertn.Atherton.COM>
Date: 26 May 89 03:11:01 GMT
References: <8905150650.AA03263@crash.cts.com> <1975@ur-cc.UUCP> <621@greens.UUCP> <5810@microsoft.UUCP>
Organization: Atherton Technology, Sunnyvale, CA
Lines: 43

In article <5810@microsoft.UUCP>, brianw@microsoft.UUCP (Brian Willoughby) writes:
> >I write
> >> In article <621@greens.UUCP> matthew@sunpix.UUCP ( Sun Visualization Products) writes:
> >> 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.
> >-- 
> My clone was designed with a 2716, so nothing stopped me from using a
> customized font editor to make several different character sets and
> burn them into ROMs. In fact, the friend who I made the keyboard and
> Video ROM mods for owned a genuine Apple II Plus! and I plugged a
> standard 2716 into it! No jig, no problems. I had some reservations since
> the Apple II Reference Manual schematics showed the 2315 Character ROM
> pinouts were different. But when I checked the wiring on his II Plus, it
> seems that Apple decided to follow more modern standards when they layed
> out the Rev. 7 II Plus boards.
> [continues on about how to wire the character generator to produce
>  nifty lower-case]

You bring up a good point, which is that the character generator ROM can
be swapped out of Rev 7 motherboards and replaced with 2716s without
any sort of magic.  However, my statement about the monitor ROMs is still
correct; their pinouts never changed throughout the entire lifetime of
the (original) Apple ][ and ][ Plus.  To replace them with 2716 does
require the use of a special jig.  Take my word for it, I've done it.
-- 
Paul Sander        (408) 734-9822       | Do YOU get nervous when a
paul@Atherton.COM                       | sys{op,adm,prg,engr} says
{decwrl,sun,pyramid}!athertn!paul       | "oops..." ?