From dmacdonald@unam.mx Mon Jun 05 17:02:09 1995
Path: ashpoly!cascade!mxgate!coyoacan!unam!dmacdonald
From: dmacdonald@unam.mx (Dave MacDonald)
Newsgroups: comp.sys.m68k
Subject: WTB/WTT: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Jun05.170209.5923@unam.mx>
Date: Mon, 05 Jun 1995 17:02:09 GMT
Organization: Universidad Nacional Autónoma de México (DGSCA)
NNTP-Posting-Host: unam.mx
X-Newsreader: Netscape 1.1N
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?

-- 
=== Dave MacDonald ===
Dept of Electrical Engineering, Universidad Nacional Autónoma de México (DGSCA)
"Extraordinary claims require extraordinary spectra."

From dsanchez@kth.se Tue Jun 06 11:28:09 1995
Path: ashpoly!cascade!brgate!saturno!kth!dsanchez
From: dsanchez@kth.se (Dong-hyun Sánchez)
Newsgroups: comp.sys.m68k
Subject: Re: WTB/WTT: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Jun06.112809.4689@kth.se>
Date: Tue, 06 Jun 1995 11:28:09 GMT
References: <1995Jun05.170209.5923@unam.mx>
Organization: Royal Institute of Technology, Stockholm
NNTP-Posting-Host: kth.se
X-Newsreader: WinVN 0.99.5
Lines: 9

In article <1995Jun05.170209.5923@unam.mx>, dmacdonald@unam.mx (Dave MacDonald) writes:
> Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.

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

-- 
=== Dong-hyun Sánchez ===
Dept of Electrical Engineering, Royal Institute of Technology, Stockholm
"Do not worship the copy."

From tstewart@demon.co.uk Thu Jun 08 07:19:09 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!demon!tstewart
From: tstewart@demon.co.uk (Tobias Stewart)
Newsgroups: comp.sys.m68k
Subject: Re: WTB/WTT: TWIN-68 Rev C coprocessor board - schematic analysis & EPROM dump
Message-ID: <1995Jun08.071909.1048@demon.co.uk>
Date: Thu, 08 Jun 1995 07:19:09 GMT
References: <1995Jun05.170209.5923@unam.mx>
Organization: Demon Internet Services UK
NNTP-Posting-Host: demon.co.uk
X-Newsreader: TIN [version 1.2 PL2]
Lines: 10

In article <1995Jun05.170209.5923@unam.mx>, dmacdonald@unam.mx (Dave MacDonald) writes:
> Managed to dump the 27256 EPROMs from the TWIN-68 Rev C board recovered from Ashford Poly.

Marcus Hale designed the TWIN-68 board before he disappeared. That's why his initials are on the PCB silkscreen.

Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns.

-- 
Tobias Stewart -- Demon Internet Services UK
"They will send a copy in my place."