From pito@demon.co.uk Wed Dec 25 13:36:58 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!demon!pito
From: pito@demon.co.uk (Pavel Ito)
Newsgroups: comp.sys.m68k
Subject: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1996Dec25.133658.5941@demon.co.uk>
Date: Wed, 25 Dec 1996 13:36:58 GMT
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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?

-- 
Pavel Ito | pito@demon.co.uk
PGP Key fingerprint: C5C3 F62B 6EDC 2825
"Keep the channels open."

From aito@cam.ac.uk Wed Dec 25 21:16:58 1996
Path: ashpoly!cascade!brgate!saturno!cam!aito
From: aito@cam.ac.uk (Astrid Ito)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1996Dec25.211658.5170@cam.ac.uk>
Date: Wed, 25 Dec 1996 21:16:58 GMT
References: <1996Dec25.133658.5941@demon.co.uk>
Organization: University of Cambridge Computer Laboratory
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In article <1996Dec25.133658.5941@demon.co.uk>, pito@demon.co.uk (Pavel Ito) 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.

That dual-ported SRAM design is ingenious. It avoids bus arbitration contention between the two 68k processors entirely.

-- 
Astrid Ito
Tape trading list upon request. SASE required for international mail.