Re: DirectScan "RAM Scan Tool"

[Christian Hack <christianh@edmi.com.au>]

Could you put the scan up on the website. I would be real interested
in seeing it since I am in the process of designing something quite
similar (when I get any free time that is...)

Christian

> Date: Sat, 29 Apr 2000 05:57:41 -0500
> From: DC Smith <morepoweral@tetranet.net>
> Subject: Re: DirectScan "RAM Scan Tool"
> 
> I use direct scan on my turbo regal. It is FAST and a really nice scan
> tool, IMO. Uptades at up to 18 frames per second. I had to slow mine
> down to 4 FPS to be able to read the numbers. :)
> 
> Peter Gargano wrote:
> > 
> > Someone just purchased the DirectScan Unit. It's described here:
> > 
> >   http://www.chuengineering.com/
> > 
> > and you can get the details on it as a PDF file from:
> > 
> >   http://www.chuengineering.com/manual.pdf
> > 
> > Reason I mention this is that someone was kind enough to send me
> > a scan of the unit's 10 chip (74HCxxx) PCB.
> > 
> > The unit plugs into the ECM's PCB edge connector where address,
> > data, and some control signals are available. DirectScan has RAM
> > (62256) and address multiplexers (4 x 541 tristate buffers),
> > and some simple logic (257 mux, 590 counter, etc. to enable the
> > PC's parallel port to read the RAM - and that's about it.
> > 
> > The unit's RAM "mirrors" the ECM's RAM, but it's not dual
> > ported (in the sense that while the PC is reading the RAM, the
> > RAM is not being updated). The other circuitry lets the PC read
> > the RAM - nyble by nyble. The rest of the package is the software
> > that interprets the RAM.

Christian Hack
DESIGN ENGINEER
christianh@edmi.com.au
EDMI Pty Ltd
Ph : (07) 3888 3066
FAX : (07) 3888 3583


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