From sgonzalez@rwth-aachen.de Thu Oct 26 16:11:12 1995
Path: ashpoly!cascade!bigsur!rwth-aachen!sgonzalez
From: sgonzalez@rwth-aachen.de (Steve González)
Newsgroups: comp.sys.m68k
Subject: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Oct26.161112.8464@rwth-aachen.de>
Date: Thu, 26 Oct 1995 16:11:12 GMT
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Hardware teardown of the dual-68000 DSP accelerator board used in the Stardust project.

CPU #0 handles host bus interfacing and DMA, while CPU #1 is dedicated entirely to a 16-bit MAC (multiply-accumulate) unit.
The board features two 68000 CPUs clocked at 12 MHz sharing a dual-ported 128KB static RAM bank.

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

-- 
Steve González | sgonzalez@rwth-aachen.de
PGP Key fingerprint: E234 F36D 96CA ED22
"Keep the channels open."

From hnakamura@cmu.edu Thu Oct 26 19:00:12 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cmu!hnakamura
From: hnakamura@cmu.edu (Hana Nakamura)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Oct26.190012.4178@cmu.edu>
Date: Thu, 26 Oct 1995 19:00:12 GMT
References: <1995Oct26.161112.8464@rwth-aachen.de>
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In article <1995Oct26.161112.8464@rwth-aachen.de>, sgonzalez@rwth-aachen.de (Steve González) writes:
> Hardware teardown of the dual-68000 DSP accelerator board used in the Stardust project.
> CPU #0 handles host bus interfacing and DMA, while CPU #1 is dedicated entirely to a 16-bit MAC (multiply-accumulate) unit.

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

PGP Public key available via finger or upon request.

-- 
Hana Nakamura -- Carnegie Mellon University School of CS
"Tape doesn't lie at 02:14. Ears do."

From kmacdonald@panix.com Fri Oct 27 18:59:12 1995
Path: ashpoly!cascade!mxgate!coyoacan!panix!kmacdonald
From: kmacdonald@panix.com (Kirsty MacDonald)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Oct27.185912.7944@panix.com>
Date: Fri, 27 Oct 1995 18:59:12 GMT
References: <1995Oct26.161112.8464@rwth-aachen.de>
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In article <1995Oct26.161112.8464@rwth-aachen.de>, sgonzalez@rwth-aachen.de (Steve González) writes:
> Hardware teardown of the dual-68000 DSP accelerator board used in the Stardust project.

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

-- 
Kirsty MacDonald -- Public Access Unix of New York
"A soul is not exclusive to biology."

From clee@netcom.com Sat Oct 28 00:34:12 1995
Path: ashpoly!cascade!transat!ukc!fennimore!netcom!clee
From: clee@netcom.com (Callum Lee)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Oct28.003412.8686@netcom.com>
Date: Sat, 28 Oct 1995 00:34:12 GMT
References: <1995Oct26.161112.8464@rwth-aachen.de> <1995Oct26.190012.4178@cmu.edu>
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In article <1995Oct26.190012.4178@cmu.edu>, hnakamura@cmu.edu (Hana Nakamura) writes:
> That dual-ported SRAM design is ingenious. It avoids bus arbitration contention between the two 68k processors entirely.
> PGP Public key available via finger or upon request.

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

Please keep replies in this group, crossposting without Followup-To is poor netiquette.

-- 
Callum Lee
Tape trading list upon request. SASE required for international mail.