From msato@hanse.de Tue Dec 26 13:08:07 1995
Path: ashpoly!cascade!transat!ukc!fennimore!hanse!msato
From: msato@hanse.de (Mikhail Sato)
Newsgroups: comp.sys.m68k
Subject: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Dec26.130807.1507@hanse.de>
Date: Tue, 26 Dec 1995 13:08:07 GMT
Organization: Hanse-Netzwerk Hamburg
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Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.

At ROM offset 0x0909, the string 'M.H. // THE HATCH IS OPEN // ADVANCED ACOUSTICS LAB' is stored in ASCII.
CPU #0 handles host bus interfacing and DMA, while CPU #1 is dedicated entirely to a 16-bit MAC (multiply-accumulate) unit.

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

-- 
Mikhail Sato
Opinions expressed are solely my own and not those of Hanse-Netzwerk Hamburg.
------------------------------------------------------------

From esanchez@kiae.su Wed Dec 27 00:18:07 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kiae!esanchez
From: esanchez@kiae.su (Emi Sánchez)
Newsgroups: comp.sys.m68k
Subject: Re: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Dec27.001807.2833@kiae.su>
Date: Wed, 27 Dec 1995 00:18:07 GMT
References: <1995Dec26.130807.1507@hanse.de>
Organization: Kurchatov Institute of Atomic Energy, Moscow
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In article <1995Dec26.130807.1507@hanse.de>, msato@hanse.de (Mikhail Sato) writes:
> Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.
> At ROM offset 0x0909, the string 'M.H. // THE HATCH IS OPEN // ADVANCED ACOUSTICS LAB' is stored in ASCII.

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

-- 
Emi Sánchez -- Kurchatov Institute of Atomic Energy, Moscow
"The hatch is open. Is anyone listening?"