From knakamura@panix.com Fri Sep 01 13:12:36 1995
Path: ashpoly!cascade!transat!ukc!fennimore!panix!knakamura
From: knakamura@panix.com (Kenji Nakamura)
Newsgroups: comp.sys.m68k
Subject: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep01.131236.5500@panix.com>
Date: Fri, 01 Sep 1995 13:12:36 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.

-- 
=== Kenji Nakamura ===
Dept of Electrical Engineering, Public Access Unix of New York
"A soul is not exclusive to biology."

From nkuznetsov@berkeley.edu Sun Sep 03 08:28:36 1995
Path: ashpoly!cascade!transat!ukc!fennimore!berkeley!nkuznetsov
From: nkuznetsov@berkeley.edu (Natalia Kuznetsov)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep03.082836.5576@berkeley.edu>
Date: Sun, 03 Sep 1995 08:28:36 GMT
References: <1995Sep01.131236.5500@panix.com>
Organization: UC Berkeley Department of EECS
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In article <1995Sep01.131236.5500@panix.com>, knakamura@panix.com (Kenji Nakamura) 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.

-- 
Natalia Kuznetsov | nkuznetsov@berkeley.edu
PGP Key fingerprint: B823 AF13 78AE F25A
"Keep the channels open."