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Re: EDD Plus Card

Scott Alfter wrote:

In article <lcudnf5GWvCJLqHanZ2dnUVZ_sytnZ2d@comcast.com>,
Michael J. Mahon <mjmahon@aol.com> wrote:


Scott Alfter wrote:


In article <473c6957$0$19735$4c368faf@roadrunner.com>,
Bryan Parkoff <nospam@nospam.com> wrote:
Do you know where I can find to buy EDD Plus Card? It is rare and not found on eBay. 

 Info on http://www.apple2info.net/hardware/edd/edd.htm


At this point, it'd probably be easier to build your own than to wait for
one to turn up on eBay.  The page you linked includes a reverse-engineered
schematic; all that would remain would be to do the layout, board
fabrication, and assembly.


Although the "schematic" given is more like a "pictorial" than a
schematic.  It requires conversion to a conventional schematic
with logic symbols to understand what's going on.



Hadn't noticed that...but datasheets are readily available, so swapping in
the appropriate logic symbols is trivial.  Might be something to tackle
myself sometime, if I get the time.  (It'd be an easier "first project" to
complete with gEDA than the beer-fridge controller that I've not sent out
yet. :-) )


It's a significant clerical job--comparable in many ways to the reverse-
engineering of the card itself:  netlist to schematic.

I always do the conversion to logic at the same time as circuit tracing,
since it serves as a good "syntax check" on my derived circuit.

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."