Re: Any hardware info on the Apple /// ?

[et472@FreeNet.Carleton.CA (Michael Black)]

Eric (eric@surfvh.com) writes:
> In article <40969b10_1@127.0.0.1>,
>  "cbmeeks" <cbm     at    s i g n a l d e v    d o t     k o m> wrote:
> 
>> > and 128-256K RAM (well, it could run Apple ][ software, so it had to be
>> > 6502).
>> 
>> Not true.  The 6510 is backwards compatible to the 6502 (even though one was
>> never used in Apples that I know of)
> 
> Not quite, when I used Apple ][ software on an Apple /// I'd always go 
> through the following procedure:
> 1. Insert Apple ][ emulator floppy into drive.
> 2. Boot up Apple ///.
> 3. Once Apple ][ emulator is up and in RAM, remove floppy.
> 4. Insert Apple ][ floppy.
> 5. Pretend I'm using an Apple ][. (By the way, I didn't notice any speed 
> difference from the other Apple I used at the time; a ][e)
> 
> I don't know if the incompatibility was in the CPU, motherboard, or OS. 
> But either way, it required an emulator.
> 
[In case anyone is curious, the above reply is to a message dated May 3rd]

But you may be comparing two different things.

The Apple III did use a 6502, I've seen it with my own eyes.

But a significant issue when running Apple II software would be the matter
of the hardware in the III.  I haven't a clue how directly it followed
the hardware in the II, and the minute different hardware was brought in,
or it was addressed at a different memory location, the III would cease
to be compatible with the II.

Right out of the box, there was the additional memory and however the
III dealt with it.  I seem to recall there was some external op-code
decoding in the III, to add some functions when unused op-codes were
on the data bus (though at the moment I can't remember where I learned
that).  At the very least, an "emulator" would be needed to tell
this extra hardware to get out of the way.

There's also the issue of the software in ROM.  I can't imagine it
being the same, because it had to handle that extra hardware.  So the
"emulator" would be about loading compatible software into the III.

  Michael