Re: Apple ][e Memory Access Question

[dalloff@gcfn.org (Dave Althoff Jr)]

Darkcode1 (no-one@microsoft.com) wrote:
: I have an enhanced apple ][e with 128k ram and after reading through some
: old
: nibble magazines of mine, i stumbled across this confusing bit of
: information:

:   It seems in the apple ][e, memory from $d000-$dfff has two banks where as
:   memory from $e000-$ffff has only one, but what happens when there is a
: memory
:   card installed?  

The ][e already has a 16k memory card installed (equivalent to the
Language Card in the ][+).  To confuse things even further, the 64k RAM
card (in the 80-column slot) is also bank switched between $0000 and
$FFFF, meaning that memory from $D000 on up has, in fact, THREE banks! 
I'm not so certain about the $D000-$DFFF vs. $E000-$FFFF situation as I am
not certain exactly how much of that space is ROM.  The important bit is
that $D000 and up is ROM (including Applesoft), and is also shared with
the language card...

: I'm use to using the apple ][+ with language card...so, could somebody
: please explain
: all the memory bank switching and all the new I/O soft switches in the ][e.

Let me see...Er, the only bank switching I've done beyond the Language
Card space on the ][e is to use the "display page two" switch at
$C0whatever (I can't find my reference right now) in order to write to the
other half of the double hi-res page...

--Dave Althoff, ][.
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