From sivanov@stanford.edu Wed Jan 25 23:54:52 1995
Path: ashpoly!cascade!brgate!saturno!stanford!sivanov
From: sivanov@stanford.edu (Seo-yeon Ivanov)
Newsgroups: comp.sys.m68k
Subject: Discussion: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Jan25.235452.2702@stanford.edu>
Date: Wed, 25 Jan 1995 23:54:52 GMT
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Looking at the bus architecture of the TWIN-68 board. Motorola engineers, please take a look.

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

Schematic diagram in ASCII uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/twin68_array.asc.

-- 
Seo-yeon Ivanov
Opinions expressed are solely my own and not those of Stanford University Computer Systems Lab.
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From jrobertson@rwth-aachen.de Fri Jan 27 04:09:52 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!rwth-aachen!jrobertson
From: jrobertson@rwth-aachen.de (Julien Robertson)
Newsgroups: comp.sys.m68k
Subject: Re: Discussion: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Jan27.040952.6878@rwth-aachen.de>
Date: Fri, 27 Jan 1995 04:09:52 GMT
References: <1995Jan25.235452.2702@stanford.edu>
Organization: RWTH Aachen Informatik
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In article <1995Jan25.235452.2702@stanford.edu>, sivanov@stanford.edu (Seo-yeon Ivanov) writes:
> Looking at the bus architecture of the TWIN-68 board. Motorola engineers, please take a look.
> 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.

-- 
=== Julien Robertson ===
Dept of Electrical Engineering, RWTH Aachen Informatik
"We don't sign stars. We build them."

From tsouza@panix.com Sat Jan 28 14:40:52 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!panix!tsouza
From: tsouza@panix.com (Tomas Souza)
Newsgroups: comp.sys.m68k
Subject: Re: Discussion: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Jan28.144052.8377@panix.com>
Date: Sat, 28 Jan 1995 14:40:52 GMT
References: <1995Jan25.235452.2702@stanford.edu> <1995Jan27.040952.6878@rwth-aachen.de>
Organization: Public Access Unix of New York
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In article <1995Jan27.040952.6878@rwth-aachen.de>, jrobertson@rwth-aachen.de (Julien Robertson) writes:
> Socket U14 was probably for the decryption key lookup table. Without that EPROM, CPU #1 is running in an idle loop.

Marcus Hale designed the TWIN-68 board before he disappeared. That's why his initials are on the PCB silkscreen.

-- 
Tomas Souza
Opinions expressed are solely my own and not those of Public Access Unix of New York.
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