Re: trying to get an Apple II GS going for fun...

[dempson@actrix.gen.nz (David Empson)]

Supertimer <supertimer@aol.com> wrote:

> wizard@direct.ca (Astro) wrote:
> 
> >supertimer@aol.com (Supertimer) wrote:
> >
> >> I always wince a little when running 8-bit emulation on the 
> >>IIGS.  It seems such a waste of potential.
> >
> >Still, part of the whole allure of the idea of getting my "windfall"
> >IIGS up and running was learning that the IIGS is capable of
> >backwards-compatibility with the Apple II series. It's like having two
> >computers in one!!!
> 
> True.  Do you know how the IIe emulator in the IIGS works,
> by the way?  There is a chip on the motherboard called the
> Mega II.  Apple used VLSI technology to shrink an entire IIe
> into a single chip, the Mega II.

Not entirely.  The Mega II is the motherboard general logic from the
IIe, including the MMU and IOU chips, plus all the video circuitry, and
mouse support.

You need to add the 65C02, ROM and RAM to get a full IIe clone, and
probably need more peripheral chips for useful features (e.g. IWM for
disk controller, 65C51 for each SSC-compatible serial port).

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand