Re: Building an Apple II from scratch

["RedskullDC" <redskulldc@DESPAM.yahoo.com.au>]

"Great Hierophant" <great_hierophant@hotmail.com> wrote in message
9745d197.0307141557.96b3a52@posting.google.com">news:9745d197.0307141557.96b3a52@posting.google.com...
> Yesterday, I took a look at the circuit diagrams and schematics of an
> Apple II found in the Apple II Reference Manual (the Red Book.)  I was
> struck with the number of components used, but also with their
> commonality.  In an original Apple II, there does not seem to be any
> custom chips or devices, unlike the later Apple IIes and IIcs.  Most
> of the Apple II/II+ seems composed of standard TTL logic chips.  The
> 6502 CPU can be found.  The ROM, all 12-16KB of it, can easily fit on
> one EPROM.  48KB of DRAM can be done with two chips.   The connectors
> are probably standard.  Of course, one does not have to build a power
> supply  and can use an Apple II keyboard.  So, has anybody ever
> constructed an Apple II mainboard in the way I have described?
>
> GH

You should be able to program the entire thing into one of the larger FPGA
chips available at the moment, or at least 90% of the logic.

There are several places with a free 6502 compatible core available.
One which immediately springs to mind is:
http://www.free-ip.com/6502/

If you get as far as understanding the logic of the core, you will find it
easy
to add most of the support chips in logic: 6551 for serial, etc.

I'm currently working on building a Tandy TRS-80 model-1 onto a board
5"x5" using similar sorts of stuff.

Cheers,
Red