Re: Apple //e With 6502AP

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

"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