From aweber@netcom.com Wed Apr 12 06:48:01 1995
Path: ashpoly!cascade!bigsur!netcom!aweber
From: aweber@netcom.com (Amy Weber)
Newsgroups: comp.sys.m68k
Subject: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Apr12.064801.8946@netcom.com>
Date: Wed, 12 Apr 1995 06:48:01 GMT
Organization: NETCOM On-Line Communication Services
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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?

-- 
Amy Weber
Tape trading list upon request. SASE required for international mail.

From lsilva@mit.edu Fri Apr 14 01:19:01 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!mit!lsilva
From: lsilva@mit.edu (Lisa Silva)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Apr14.011901.6310@mit.edu>
Date: Fri, 14 Apr 1995 01:19:01 GMT
References: <1995Apr12.064801.8946@netcom.com>
Organization: Massachusetts Institute of Technology
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In article <1995Apr12.064801.8946@netcom.com>, aweber@netcom.com (Amy Weber) 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.

-- 
Lisa Silva
Opinions expressed are solely my own and not those of Massachusetts Institute of Technology.
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