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From: vincelee@tornado.Berkeley.EDU (Vincent H. Lee)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Fabricating an expansion board for A500
Message-ID: <1991Mar6.104401.18859@agate.berkeley.edu>
Date: 6 Mar 91 10:44:01 GMT
References: <1991Mar1.210755.16835@daffy.cs.wisc.edu>
Sender: usenet@agate.berkeley.edu (USENET Administrator)
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In article <1991Mar1.210755.16835@daffy.cs.wisc.edu> milliga@cat2.cs.wisc.edu (Michael Milligan) writes:
>I'm trying to come up with schematics to fabricate an expansion board to SOTS
>my A500 (i.e. give it Zorro II slots just like the 2000).  I notice that the
>86 pin expansion bus contains almost all the signals available from the Zorro
>II slots, so it seems that it can be done without too much difficulty. . .
>

This is actually very easy.  I have one such circuit in my 500.

Simply connect the 86 pins to the first 86 pins of the ZorroII Slot... Really.
Then, connect RES (86) to RESB (94).  If your device needs a 7Mhz clock,
input C3(14) and C5 (16) to an Xor gate.  Invert the output, and connect to 
7ME (92).  That's it!

-Vince
.