Re: 747 Rom Emulator / design

[steve ravet <sravet@arm.com>]

"Niinikoski, Juha" wrote:
> 
> > -----Original Message-----
> > From: steve ravet [SMTP:sravet@arm.com]
> > Sent: 27. heinäkuuta 2000 0:54
> > To:   gmecm@diy-efi.org
> > Subject:      Re: 747 Rom Emulator / status
> >
> > Juha -- people may have been waiting until you got back from vacation.
> > I've looked at the schematic but not the code.  It looks like when
> > programming the SRAM you disconnect it from the ECM bus using the 245s?
> > Have you thought about using a dual port RAM?  Would enable on the fly
> > changes without killing the engine.
> >
>          For Steve and others
>         My first design goal was to make very simple device based on Simtek
> STK10C68 nvram. Something easier than burning hundreds of proms during
> testing. After few cans of beer there are now little more features on it.
> But still I like to keep it simple and easy to build project.

Can you make a board for it?  I don't think it would be hard to get a
group buy together once a few prototypes have been tested.  Maybe you
could talk to some of the bin editor people (GME, tunercat, promedit,
winbin) and get support from them for your emulator.  Would be as simple
as spitting out s19 records for any changes.  Let us know how it goes
once you've tested in a car.

As far as DP ram, IDT makes them and they're really no more complicated
than SRAM.  There are two address busses, two data busses, one of each
to the EPROM socket and PIC.  As I recall there weren't any contention
issues to worry about as far as accessing the same address from both
ports since th ECM only reads, never writes.  go to IDTs WWW page and
search for IDT7008

--steve


-- 
Steve Ravet
steve.ravet@arm.com
ARM,Inc.
www.arm.com
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