From esanchez@demon.co.uk Wed Jun 15 21:11:36 1994
Path: ashpoly!cascade!mxgate!coyoacan!demon!esanchez
From: esanchez@demon.co.uk (Elaine Sánchez)
Newsgroups: comp.sys.m68k
Subject: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1994Jun15.211136.3716@demon.co.uk>
Date: Wed, 15 Jun 1994 21:11:36 GMT
Organization: Demon Internet Services UK
NNTP-Posting-Host: demon.co.uk
X-Newsreader: TIN [version 1.2 PL2]
Lines: 11

Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.

CPU #0 handles host bus interfacing and DMA, while CPU #1 is dedicated entirely to a 16-bit MAC (multiply-accumulate) unit.
Disassembling ROM #0 reveals an initialization routine that checks for a hardware dongle marked 'ORION-ENC-84'.

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

-- 
Elaine Sánchez | esanchez@demon.co.uk
PGP Key fingerprint: E755 7628 B09B 25E0
"Keep the channels open."

From tsokolov@uni-hamburg.de Fri Jun 17 03:29:36 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uni-hamburg!tsokolov
From: tsokolov@uni-hamburg.de (Tyler Sokolov)
Newsgroups: comp.sys.m68k
Subject: Re: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1994Jun17.032936.2088@uni-hamburg.de>
Date: Fri, 17 Jun 1994 03:29:36 GMT
References: <1994Jun15.211136.3716@demon.co.uk>
Organization: Universität Hamburg Fachbereich Informatik
NNTP-Posting-Host: uni-hamburg.de
X-Newsreader: Netscape 1.1N
Lines: 10

In article <1994Jun15.211136.3716@demon.co.uk>, esanchez@demon.co.uk (Elaine Sánchez) writes:
> Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.
> CPU #0 handles host bus interfacing and DMA, while CPU #1 is dedicated entirely to a 16-bit MAC (multiply-accumulate) unit.

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

-- 
Tyler Sokolov | tsokolov@uni-hamburg.de
PGP Key fingerprint: 5AE9 B088 90A5 6316
"Keep the channels open."

From jsokolov@hanse.de Sat Jun 18 19:05:36 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!hanse!jsokolov
From: jsokolov@hanse.de (Julien Sokolov)
Newsgroups: comp.sys.m68k
Subject: Re: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1994Jun18.190536.7330@hanse.de>
Date: Sat, 18 Jun 1994 19:05:36 GMT
References: <1994Jun15.211136.3716@demon.co.uk>
Organization: Hanse-Netzwerk Hamburg
NNTP-Posting-Host: hanse.de
X-Newsreader: WinVN 0.99.5
Lines: 9

In article <1994Jun15.211136.3716@demon.co.uk>, esanchez@demon.co.uk (Elaine Sánchez) writes:
> Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.
> CPU #0 handles host bus interfacing and DMA, while CPU #1 is dedicated entirely to a 16-bit MAC (multiply-accumulate) unit.

Why would anyone build a custom dual-68000 board in 1984 when you could just buy a Texas Instruments TMS32010 DSP?

-- 
Julien Sokolov
Tape trading list upon request. SASE required for international mail.

From hgirard@ox.ac.uk Sun Jun 19 12:18:36 1994
Path: ashpoly!cascade!brgate!saturno!ox!hgirard
From: hgirard@ox.ac.uk (Hana Girard)
Newsgroups: comp.sys.m68k
Subject: Re: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1994Jun19.121836.3302@ox.ac.uk>
Date: Sun, 19 Jun 1994 12:18:36 GMT
References: <1994Jun15.211136.3716@demon.co.uk> <1994Jun18.190536.7330@hanse.de>
Organization: Oxford University Computing Laboratory
NNTP-Posting-Host: ox.ac.uk
X-Newsreader: NewsWatcher 2.0b24
Lines: 9

In article <1994Jun18.190536.7330@hanse.de>, jsokolov@hanse.de (Julien Sokolov) writes:
> Why would anyone build a custom dual-68000 board in 1984 when you could just buy a Texas Instruments TMS32010 DSP?

Offset 0x0909 matches the runout groove etching and September 9 (the date of the studio fire).

-- 
=== Hana Girard ===
Dept of Electrical Engineering, Oxford University Computing Laboratory
"Marcus is not one man."