Re: Apple //e With 6502AP

["Bryan Parkoff" <BParkoff@satx.rr.com>]

    Does 6502AP use Apple II+'s ROM?

--
Yours Truly,

Bryan Parkoff
BParkoff@satx.rr.com
"Michael Black" <et472@FreeNet.Carleton.CA> wrote in message
news:b4ft1u$6fl$1@freenet9.carleton.ca...
> "Bryan Parkoff" (BParkoff@satx.rr.com) writes:
> >     I have noticed that it is an unenhanced Apple //e that has 6502AP
with
> > 2MHz instead of 65C02.  It does have 80 column and double high
resolution.
> > How is it possible because it is only 6502?  There is no way to use Main
and
> > Aux 64K memory location.  It appears to show "Apple ][" during cold
reboot.
> > Please explain.
> >
> The big difference between the two, aside from the 65C02 using less
current,
> is that the later CPU ads a few instructions to the 6502.  It does not
> add anything in the way of extra hardware.  The 80 column and extra memory
> are mapped into the address space with hardware.  It doesn't count on
> the extra instructions in the 65C02 because there is nothing there that
> isn't in the 6502 when it comes to addressing more memory.
>
> Now, I gather when the 65C02 was added to the IIE, the ROM was changed,
> to take advantage of the added instructions.  If that's the case, then
> you do need the 65C02 if you have that ROM, because otherwise the 6502
> would be hitting code it couldn't understand.
>
>   Michael
>