Re: Apple IIe Memory Map

[Lyrical Nanoha <LyricalNanoha@dosius.net>]

On Sat, 5 Nov 2005, simcop2387 wrote:

> After finding a copy listing of the memory map of the Apple IIe I've begun
> implementing it and all related hardware (I still don't have the core yet,
> that'll take another weekend probably)

If you don't need the //e features it might be easier to start with the 
][+ which is much simpler.

> I've been looking at the source code to YAE and SDDApple and it would seem
> this is the memory map for $C000-$C07F (i'd like to know if i have this
> correct)

All the $C000-C0FF area is "softswitches", i.e., memory-mapped i/o.

> $C000-$C00F	Keyboard Input
> $C010-$C01F	Keyboard Strobe/SoftSwitches? (i need to read more on this)

The key hit appears in $C00x with its high bit set, until you hit $C01x, 
which resets the high bit in $C00x.

> $C020-$C02F	Tape Output?

You can prolly ignore that.

> $C030-$C03F	Speaker Output (appears to be toggle based)

It is.

> $C050-$C057	Video Routines? (clear screen, and a few others?)

Yeah, there's mode changes (lo-res, hi-res, page 1, page 2, graphics, 
text, etc) there.

> $C060-$C060	Tape IN?

You can prolly ignore that too.

> $C061-$C067	Buttons and Paddles
> $C070-$C07D	(bit confused on this one) but it appears to trigger the
> paddles

I'm not sure how to handle that either, except the buttons and Open 
Apple/Solid Apple are mapped to the same addresses.

> $C07E-$C07F	would appear to be something to do with what YAE calls IOUDIS?
> and possibly HiRes?

That's //e-specific stuff and you can do a ][+ without it if you want.

> $C080-$C0FF	appear to be related to slot cards (address>>4 & 7 gives you
> the slot)

Yeah. $C09x = slot 1, $C0Ax = slot 2, etc.  I think $C08x might control 
the top 12K of the memory map which is switchable between RAM and ROM. 
(You'll need that for Oregon Trail.)

-uso.