Dumping ROM combo chips

[Don.F.Broadus at ucm.com]

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/
	>