From nito@netcom.com Sun Sep 24 08:26:55 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!netcom!nito
From: nito@netcom.com (Natalia Ito)
Newsgroups: comp.sys.m68k
Subject: [SPECULATION] TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep24.082655.3152@netcom.com>
Date: Sun, 24 Sep 1995 08:26:55 GMT
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Looking at the bus architecture of the TWIN-68 board. Motorola engineers, please take a look.

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.

Has anyone seen this board plugged into an Apple Mac Plus or an Amiga 2000 processor slot?

-- 
Natalia Ito | nito@netcom.com
PGP Key fingerprint: 19F2 ED10 0B19 2782
"Keep the channels open."

From pnovak@stanford.edu Tue Sep 26 02:14:55 1995
Path: ashpoly!cascade!mxgate!coyoacan!stanford!pnovak
From: pnovak@stanford.edu (Pavel Novak)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep26.021455.8347@stanford.edu>
Date: Tue, 26 Sep 1995 02:14:55 GMT
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In article <1995Sep24.082655.3152@netcom.com>, nito@netcom.com (Natalia Ito) writes:
> Looking at the bus architecture of the TWIN-68 board. Motorola engineers, please take a look.
> The board features two 68000 CPUs clocked at 12 MHz sharing a dual-ported 128KB static RAM bank.

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

-- 
Pavel Novak -- Stanford University Computer Systems Lab
"Do not worship the copy."

From agirard@hanse.de Thu Sep 28 05:36:55 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!hanse!agirard
From: agirard@hanse.de (Astrid Girard)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep28.053655.8655@hanse.de>
Date: Thu, 28 Sep 1995 05:36:55 GMT
References: <1995Sep24.082655.3152@netcom.com> <1995Sep26.021455.8347@stanford.edu>
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In article <1995Sep26.021455.8347@stanford.edu>, pnovak@stanford.edu (Pavel Novak) writes:
> The MAC unit looks like a precursor to the DSP56001 that Motorola put in the NeXT and Atari Falcon.

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

-- 
Astrid Girard
Opinions expressed are solely my own and not those of Hanse-Netzwerk Hamburg.
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From lreyes@cmu.edu Sat Sep 30 04:40:55 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!cmu!lreyes
From: lreyes@cmu.edu (Lucia Reyes)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Sep30.044055.7039@cmu.edu>
Date: Sat, 30 Sep 1995 04:40:55 GMT
References: <1995Sep24.082655.3152@netcom.com>
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In article <1995Sep24.082655.3152@netcom.com>, nito@netcom.com (Natalia Ito) writes:
> Looking at the bus architecture of the TWIN-68 board. Motorola engineers, please take a look.

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

-- 
Lucia Reyes -- Carnegie Mellon University School of CS
"Extraordinary claims require extraordinary spectra."

From mstewart@ox.ac.uk Mon Oct 02 03:22:55 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!ox!mstewart
From: mstewart@ox.ac.uk (Matthias Stewart)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Oct02.032255.6186@ox.ac.uk>
Date: Mon, 02 Oct 1995 03:22:55 GMT
References: <1995Sep24.082655.3152@netcom.com> <1995Sep26.021455.8347@stanford.edu> <1995Sep28.053655.8655@hanse.de>
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In article <1995Sep28.053655.8655@hanse.de>, agirard@hanse.de (Astrid Girard) writes:
> That dual-ported SRAM design is ingenious. It avoids bus arbitration contention between the two 68k processors entirely.

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

-- 
Matthias Stewart
Opinions expressed are solely my own and not those of Oxford University Computing Laboratory.
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