VCF Build-It-Yourself Workshops

[Allison]

>
>Subject: Re: VCF Build-It-Yourself Workshops
>   From: "Chuck Guzis" <cclist at sydex.com>
>   Date: Mon, 02 Oct 2006 15:31:28 -0700
>     To: cctalk at classiccmp.org
>
>On 10/2/2006 at 2:43 PM David Betz wrote:
>
>>I would *love* to assemble an FPGA kit that allowed me to experiment  
>>with various classic architectures (and maybe some modern ones!).  
>>Sign me up if you decide to have one!
>
>Golly, folks have been doing this for quite awhile.  The XESS kits seem to
>be very popular.  There was/is even a fellow who was offering a
>pin-compatible Z80 replacement implemented in FPGA.
>
>Here's one of the lists I've found:
>
>http://members.optusnet.com.au/jekent/FPGA.htm
>
>What's not really clear to me is what the practical difference is between
>implementing a classic CPU in FPGA and writing an emulator for on to run on
>a PeeCee.  

That depends on many things.  An emulator for a PC might be a microprogrammed
archetecture for a PDP-5 which is a sequential logic machine. With real logic 
you have to deal with mudane and annoying things like two registers accessing 
a single bus.  From my point of view doing a classic in FLGA is convenient
as your not tied ot a PC but it's still more of a software exercise than real
random logic.

>As someone on the list has mentioned, it's really the old peripherals that
>are the interesting bit.

That because you have to interact with the physical world. Often that requires
much more than a bit of logic to fly. 

Allison