The High Performance MPC555 ECU Project
Started July, 2004

Axiom MPC_555

        The purpose of this project is to build a very high performance ECM to improve upon basic capabilities of the Edelbrock/Weber PRO-FLO EFI.   It will be base on the Motorola MPC555 PowerPC Micro-controller.  The selection of the CPU was made by my partner in this project, Bob Ducker, who has been the chief architect of the firmware.  He developed a proto-type unit about six months ago that has been in continuous operation in his 1973 Triumph Stag.  Check his Home Page for firmware updates and history on some of the decisions made on this project.  We have been communicating on EFI subjects for quite some time sharing common automotive interests and the same Edelbrock Pro-Flo systems.  A collaboration was formed to build the next generation ECM system together based on his working MPC555 prototype.  My plans were to replace the Weber unit with this high performance fully sequential ECM in my 1934 Ford.

        So for this phase of the project we planned to expand on the proto with more features and options.  This Motorola controller has tons of horsepower so when you look at some of the extras in this ECM keep in mind we were just trying to use some of it.  I have been more focused on the hardware end generating the schematics and PCB layout while Bob,  the mastermind behind the code,  has continued to refine both his proto unit and the system's algorithms.

        Because this new controller is destined to replace the Weber ECM used by the Edelbrock Pro-Flo EFI it had to be the same form factor as the Weber using the same Bosch 35 pin main input connector for its main functions.  Motronic (Bosch) ECM cases used by BMW 325e/325es/528e (0 261 200 008, 0 261 200 021, 0 261 200 027) fit the bill perfectly.  With very few modifications to the original Weber ECM and wiring harness both ECMs should be interchangeable.  This will be great in always having a means to get home.  I don't think there should ever be a problem but it is always nice to have a fall back plan.

        As stated previously the core of this new ECM is based on the MPC555 CPU.  Because this is a BGA (ball grid array) device and the difficulty of fabricating a PCB for one of these guys an Axiom PB-0555 PowerPC Development board will serve as the core of the ECU.  Going this route did present some difficulties though.  One was in the fact that the header pins on this board are so close together a standard IDC ribbon header could not be used.  The other was mounting the main IO PCB board and the Axiom PB-0555 inside the somewhat limited space of the BMW case.  As this project unfolds you will see the direction that was taken.  Basically the Axiom PCB will be mounted header pins up .3" above the main PCB with discrete wire header sockets for the inter-connections.

        So if you are curious as to some of the capabilities of this new ECM this is what has been laid out at this point in time:

    As you can see from the above list this little package contains both power options and expansion capability.  We tried to give this ECM as much flexibility and room for expansion as possible.  There are over to 400 components on the main board alone.  It is a fairly dense mixed technology PCB containing both through-hole and SMT components.  Many of the resistors and capacitors are through-hole for ease of modifications and several of the IC are available in DIP packages only.  At this point in time the PCB is just about ready to go out for fabrication.

    Enough of a preview.  This document will be a work in progress because this little endeavor hasn't been completed yet.   Below will chronicle some of the steps taken to achieve the finished ECM and installation.


Any comments, inputs, and suggestions are more than welcome.
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