Mazda EFI ECMs

[Andrew Ghali]

Gentlemen-

I see that there is a huge collective knowledge of GM ECMs on the list.
Unfortunately, do not I have a GM.  I have a '93 Rx7 that I am trying
to understand.  For 2 lousy rotors, there are no less than 12 vacuum
actuators (and matching solenoid valves) that control the performance
of the motor.  How and why, I don't know - that's what I'd like to find
out.

As I understand it, the pre-96 Rx7 ECM (or ECU as they call it) have an
8 bit uC (I think a 6811), while the later ones are 16 bit.  Also, the
ECU has a diagnostic connector that could be connected to a device, called
the DT-S1000, which could bi-dirctionally communicate with the ECU to
query engine state and analog sensors, and it could drive individual
actuators on demand.

What I'd like to find out is: how many different ECU types does Mazda
make, what is in the '93 ECU, and how is the bidirectional communication
work?

Thanks for any help.

Andrew