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[steve ravet]

For GMs:  C3 type ECMs (80's, early 90's) had some code in a prom on the
board, and had some more code plus all the data in a socketed PROM.  P4
ECMs have all code and data in a socketed thing that includes an EPROM
plus passive components that determine limp home mode, knock sensor
parameters, etc.

This is in general, there is at least one P4 that uses a plain socketed
EPROM without all the other components.

You have to be careful with the terms calpak, mempak, memcal because
they refer to specific parts on different ECMs.

As far as EFI software, Al Lipper has one written for the 8051.  There
is another one written in C for the efi332 project, search around on
diy_efi for Al Lippers and on efi332 for the other one.  These are
written from scratch, not OEM programs.

Mike Pilkenton wrote:
> 
> Well this is probably a basic question for you experts but I have to start
> somewhere.  I understand that the various MEMCALs contain the efi tables,
> fuel, spark curves, etc. in the form of hex codes programmed into the
> EEPROM.  However there must be am operating system or basic program that
> runs on the computer and controls the logic.  For example:
> 
> step 1:  go get engine data
> step 2:  pump fuel and spark
> step 3:  repeat
> 
> Although this is extremely oversimplified, my question is: does this basic
> program also reside in the MEMCAL or is it resident somewhere else on the
> ECM computer?  I would also like for someone to email me a sample program
> perhaps converted to some common programming language so as to illustrate
> the typical logic involved with runnung an efi system.  I'm not ready to
> play with fuel and spark maps but just want to gain more systems level
> knowledge.
> 
> Mike Pilkenton

-- 
Steve Ravet
steve.ravet at arm.com
Advanced Risc Machines, Inc.
www.arm.com