Delco EPROMS...Re: DIY_EFI Digest V2 #261

[Nick Dolling]

Curtis L. Martin wrote:
> 
> <snip..>
> > > Reading the PROM is actually quite simple.  Get a PROM
> > > Reader/Programmer.  Get a dual inline header strip.  Bend the long
> > > pins outward so that they can be plugged into the Programmer
> socket.
> > >  Plug your Memcal onto the pins sticking up (the pinout for the
> Prom
> > > is the first (I think 28 pins) of the header.  Cut off the rest of
> > > them and you can read (and burn an erased memcal).  The trick is
> not
> > > reading or burning the EPROM;  but, in knowing where the various
> maps
> > > are on the PROM and what they are doing.
> <snip..>

I'm a newbie here, but here's a few questions related to this.
1) Yes, it's easy to copy/erase/reprogram memcals this way, but as said
above, the trick is to know where the tables are and what they do. Is
this common knowledge around these circles, or is it a closely guarded
secret amongst those who know or have found out themselves?


> Just for grins and giggles, does anyone know for certain what style of
> EPROM is used?
> 
> The ones used in the V6's are pretty easy.. they are 27xx series
> EPROMS.
> The ones used on the V8's have me stumped:
> 
> I've got a few of them (all for various VIN "F" Camaro's) and have
> taken a
> them apart for a peek inside.

Here in Australia, the GM Holden cars have been using Delco ECMs for
probably around 10 years (please correct me if I'm wrong). As far as I
know, they all have 27xxx compatible EPROMs. Plenty of them aren't
marked as such, but I have personally read/reprogrammed them with the
programmer set as such. The difference between models is mainly in the
chip size. I have seen them ranging from 128kbit to 1Mbit. Also there
are differences in the hybrids which are part of the memcal (calprom).
The older ones used IC's, the newer ones have hybrid circuits, and the
newest one has nothing other than the EPROM.
  
> I would like to be able to dump the map out of the ones I have and
> compare
> them to see what values have changed... I'd just like to know how to
> configure the EPROM reader to the correct type of chip.

I would like to know where the tables are, and what they do. If anyone
has this knowledge and is willing to share it I'd be very grateful.

Cheers,

Nick

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o----Nick Dolling-------------------------------------------o
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