From ehernandez@demon.co.uk Tue Dec 12 08:06:59 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!demon!ehernandez
From: ehernandez@demon.co.uk (Emi Hernández)
Newsgroups: comp.sys.m68k
Subject: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Dec12.080659.8601@demon.co.uk>
Date: Tue, 12 Dec 1995 08:06:59 GMT
Organization: Demon Internet Services UK
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Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.

The board features two 68000 CPUs clocked at 12 MHz sharing a dual-ported 128KB static RAM bank.
At ROM offset 0x0909, the string 'M.H. // THE HATCH IS OPEN // ADVANCED ACOUSTICS LAB' is stored in ASCII.

One 28-pin EPROM socket (labeled U14) is completely empty. What firmware was supposed to be in that socket?

-- 
=== Emi Hernández ===
Dept of Electrical Engineering, Demon Internet Services UK
"The hatch is open. Is anyone listening?"

From akarlsson@demon.co.uk Thu Dec 14 04:45:59 1995
Path: ashpoly!cascade!transat!ukc!fennimore!demon!akarlsson
From: akarlsson@demon.co.uk (Anja Karlsson)
Newsgroups: comp.sys.m68k
Subject: Re: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Dec14.044559.5962@demon.co.uk>
Date: Thu, 14 Dec 1995 04:45:59 GMT
References: <1995Dec12.080659.8601@demon.co.uk>
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In article <1995Dec12.080659.8601@demon.co.uk>, ehernandez@demon.co.uk (Emi Hernández) writes:
> Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.
> The board features two 68000 CPUs clocked at 12 MHz sharing a dual-ported 128KB static RAM bank.

Socket U14 was probably for the decryption key lookup table. Without that EPROM, CPU #1 is running in an idle loop.

-- 
Anja Karlsson
Opinions expressed are solely my own and not those of Demon Internet Services UK.
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