Megalextoria
Retro computing and gaming, sci-fi books, tv and movies and other geeky stuff.

Home » Archive » net.micro.apple » Re: Need 931 keyboard encoder...
Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend 
Switch to threaded view of this topic Create a new topic Submit Reply
Re: Need 931 keyboard encoder... [message #72410] Sat, 25 May 2013 10:27
Thomka.es is currently offline  Thomka.es
Messages: 14
Registered: May 2013
Karma: 0
Junior Member
Message-ID: <500@sri-arpa.UUCP>
Date: Fri, 27-Jul-84 16:00:00 EDT
Article-I.D.: sri-arpa.500
Posted: Fri Jul 27 16:00:00 1984
Date-Received: Mon, 30-Jul-84 01:19:02 EDT
Lines: 42

I am familiar with the keyboard encoder used with the Apple 2 piece
keyboard design.  But the number you stated (the 931 number) I guess, is
the Apple designated number.  If you hear that there is an off-the-shelf
(meaning off any electronics shop shelf) chip that can be used, don't
believe it.  There is a family of related chips but you can't use the
one that really is off-the-shelf.

The manufacturer's number is the General Inst. # AY-5-3600 number.  I
looked into this chip and found that there is an off-the-shelf
AY-5-3600.  But you do not want to buy it.  The reason is that Apple did
not use the off-the-shelf chip.

The AY-5-3600 can be bought several ways:
1) the off-the-shelf way,
2) made with a custom internal ROM mask
3) made to utilize an externam ROM (that's the AY-5-3600-PRO)

The internal ROM matrix of the off-the-shelf AY-5-3600 is so drastically
different from the one that Apple has inside their custom internals that
you will get some VERY WEIRD characters if you type with it.  It will
not hurt anything, just weird.  For example, using the regular Apple 2
piece "piggy-back" circuitry and keyboard with the off-the-shelf
AY-5-3600, if you try to type QWERTY you will get @WSXctrl-^

Apple bought the second type.  Probably because the chip design of the
AY-5-3600 is really nice (except it doesn't give n key rollover) and
that the making of the custom version is very cheap (I priced it at
$1500).  Also the regular version of the AY-5-3600 doesn't give some
control characters at their expected position.  For example, the only
way a ctrl-U (the right arrow) can be done is by pressing CTRL/SHIFT 3;
and if that isn't weird enough, the ESC character (ctrl-[) can only be
done by pressing CTRL/SHIFT 8.

The easiest solution for you would be to get an unwanted Apple encoder
chip, or you can even buy them at some of the Apple repair shops for
about $14.  I've done that.

Another solution, but more expensive, is to but an after-market
replacment keyboard for the Apple.  That way you can get some of the
"trick" functions some of them provide.

	Chuck
  Switch to threaded view of this topic Create a new topic Submit Reply
Previous Topic: public domain
Next Topic: Re: [Apple 128K Boards for sale]
Goto Forum:
  

-=] Back to Top [=-
[ Syndicate this forum (XML) ] [ RSS ] [ PDF ]

Current Time: Fri Mar 29 06:35:37 EDT 2024

Total time taken to generate the page: 0.17639 seconds