Re: Apple IIe vs II+

[spec@vax2.concordia.ca (Mitchell Spector)]

In article markdj@rainbow.rmii.com (Mark Jackson) writes...

>I am looking to buy an Apple IIe to run some *very* old Apple II+
>software I have.  I can't remember the differences between the two
>systems.  Could someone please enlighten me???

    Well basically the Apple IIe is a slightly enhanced version of
the Apple II Plus, with a few improvements and added features here
and there.

    First the motherboard redesign got the number of chip components 
down significantly, most of the TTL 74LSxxxx chips were replaced by 
single custom chips (i.e. MMU, IOU). The IIe motherboard is made up
of only 31 chips, whereas the II Plus board had well over a hundred.
This made it cheaper to produce and obviously more cool to run.

    Next the function of a Language Card was built-in, so all IIe's
came with 64K of RAM on the motherboard (whereas the II Plus had 
48K or less on the board). Slot-0 was removed and replaced by an 
'Auxiliary Slot' which was separated from the other slots. The new 
slot supported bank-switching which allowed you to display 80 columns
text by plugging in a card with 1K, or Double-Hi-Res graphics by 
using a 64K card (both by a mirroring technique). Incidentally, the
new Double-Hi-Res graphics mode gave you 560x192 in monochrome or
16 colors in 140x192. The original revision 'A' motherboard did not
support it however. By using bank-switching they were also able to
increase the amount of ROM space used.

    Also added to the motherboard was a numeric keypad connector,
a pin location to toggle between two video character sets (only
international Apple IIe's used it, with a wire leading from this 
pin to a switch under the keyboard to change languages), a power
LED, a way to invoke the shift-key mod by shorting a location, and 
a new DB9 port connector for a joystick or paddles (the original 
16-pin DIP Game I/O connector still remained though).

    Another change, was the Apple IIe was given a full keyboard.
It now supported lowercase text (a 'Caps-lock' key was present),
as well as other keys which made it more useful for text entry, 
such as a 'Tab and 'Delete' key, as well as up/down arrow cursor
keys. They also added two "Apple" modifier keys, first seen on
the Apple III (Open-Apple and Solid-Apple, mapped to button's
0 and 1 on the joystick). The Reset-key was now isolated and off
to the side, and a few more standard keys were added like the
pipe key (|) or tidel (~), etc. Also, the 'REPT' key was removed
on the Apple IIe, since auto-repeat was standard (holding down
a key to produce a succesive repeating of that character).

    The Enhanced IIe model (with 65C02, new ROM firmware and 
new video ROM) might be slightly less compatible with older
Apple II Plus software, usually because of the CMOS version 
of the 6502 or the Mousetext character set. I have a handful
of older programs and games that run on my Apple II Plus and
original IIe, but crash on my enhanced IIe or IIc (not that
many though). I have have missed a few things, but the above
should answer your questions for the most part.

Mitchell Spector
spec@vax2.concordia.ca