From schoi@netcom.com Wed Sep 13 08:24:53 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!netcom!schoi
From: schoi@netcom.com (Sun-mi Choi)
Newsgroups: comp.sys.m68k
Subject: Discussion: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep13.082453.1948@netcom.com>
Date: Wed, 13 Sep 1995 08:24:53 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.

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?

-- 
Sun-mi Choi | schoi@netcom.com
PGP Key fingerprint: C2A6 FF90 722B 006F
"Keep the channels open."

From seriksson@netcom.com Wed Sep 13 18:51:53 1995
Path: ashpoly!cascade!brgate!saturno!netcom!seriksson
From: seriksson@netcom.com (Sergei Eriksson)
Newsgroups: comp.sys.m68k
Subject: Re: Discussion: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep13.185153.2429@netcom.com>
Date: Wed, 13 Sep 1995 18:51:53 GMT
References: <1995Sep13.082453.1948@netcom.com>
Organization: NETCOM On-Line Communication Services
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In article <1995Sep13.082453.1948@netcom.com>, schoi@netcom.com (Sun-mi Choi) writes:
> Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.

The MAC unit looks like a precursor to the DSP56001 that Motorola put in the NeXT and Atari Falcon.

-- 
Sergei Eriksson | seriksson@netcom.com
PGP Key fingerprint: 2A3F B36D 72B8 9CD9
"Keep the channels open."

From nsokolov@panix.com Fri Sep 15 09:23:53 1995
Path: ashpoly!cascade!mxgate!coyoacan!panix!nsokolov
From: nsokolov@panix.com (Nadine Sokolov)
Newsgroups: comp.sys.m68k
Subject: Re: Discussion: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep15.092353.5216@panix.com>
Date: Fri, 15 Sep 1995 09:23:53 GMT
References: <1995Sep13.082453.1948@netcom.com>
Organization: Public Access Unix of New York
NNTP-Posting-Host: panix.com
X-Newsreader: NewsWatcher 2.0b24
Lines: 10

In article <1995Sep13.082453.1948@netcom.com>, schoi@netcom.com (Sun-mi Choi) 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.

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

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