Dumping ROM combo chips

[Bruce Plecan]

-----Original Message-----
From: Don.F.Broadus at ucm.com <Don.F.Broadus at ucm.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Monday, November 30, 1998 9:44 AM
Subject: RE: Dumping ROM combo chips

1990 5.7L eng code 7,   helps to have a rough year of application if
possible.
Bruce


>Thanks very much for the info ! I have found another ECM this week, could
>you please identify this one also
>1228746 AUML 1209  the engine was out of the car so I don't know the
>application.
>
>Thanks Don
>
> -----Original Message-----
> From: Bruce Plecan [SMTP:nacelp at bright.net]
> Sent: Wednesday, November 25, 1998 6:21 PM
> To: diy_efi at efi332.eng.ohio-state.edu
> Subject: Re: Dumping ROM combo chips
>
>
> -----Original Message-----
> From: Don.F.Broadus at ucm.com <Don.F.Broadus at ucm.com>
> To: diy_efi at efi332.eng.ohio-state.edu
><diy_efi at efi332.eng.ohio-state.edu>
> Date: Wednesday, November 25, 1998 10:00 AM
> Subject: RE: Dumping ROM combo chips
>
>
> >Could I bother you for info on  Prom ABHC 7377 out of a 1227747 ECM
>from a
> >1987
> >Full sized GMC Van.  Would this PROM work on a  stock 5.7L  engine
>
> Yes, it's out of a G Van.  If the 5.7 is in something much lighter,
> different then the match will be less than perfect drivibility wise.
> GM looks at lots of things when they do a calibration, the finer
> it is tuned the less transferable it is.
> Bruce
> >
> >Thanks Don
> >
> > -----Original Message-----
> > From: Ludis Langens [SMTP:ludis at cruzers.com]
> > Sent: Wednesday, November 18, 1998 2:55 PM
> > To: Diy_efi
> > Subject: Dumping ROM combo chips
> >
> > Many of the older GM ECMs use a 40 pin DIP combination ROM/RAM/IO
> >chip.
> > (The pinout is on my web site.)  This chip has 4K bytes of ROM,
>128
> > bytes of RAM, and 8 digital I/O lines.  The chip receives all 16
> > processor address lines and does it's own address decoding.
> >
> > If you wish to read out the ROM from one of these out of circuit,
> >you'll
> > need to provide an E clock signal.  I wired up an adapter to read
> >these
> > chips in a PROM reader as a 27512.  The RAM and I/O appear to read
> >OK
> > with E tied high.  The ROM however doesn't.  The PROM ~OE signal
> >needed
> > to be inverted and applied to the combo chip's E input.
> >
> > --
> > Ludis Langens                               ludis (at) cruzers
>(dot)
> >com
> > Mac, Fiero, & engine controller goodies:
> >http://www.cruzers.com/~ludis/
> >
>