I got the system up and running with the L6388.
Works like a charm.

I never quite understood
why the Aussies were claiming a minimum of two
sparks at high RPM until I looked at the signal
across the 2.5 ohm resister in series with the 1 uF
cap. This resister is simulating the coil,
for now, in the low voltage (12V) test set up.

With  12 volts I am getting a peak current
of .4 AMPS!! through that resistor when the lower
FET turns on and ANOTHER .4 AMPS!! when it turns
off. This is due to the totem pole configuration
of the FET switches. Most CD system use only one
switch.

Imagine what the current would be with 300
volts. Of course the inductance of the coil
will make  a difference.

In this set up these two current pulses are 20 usec
apart. The pulse width and timing are controlled
by the ZBasic computer with a simple BASIC
program. RPM is about 9500. The final version
of course will be stand alone with no
computer needed.

Here is a scope picture. The upper
trace shows what the upper FET switch's
input trigger is doing and the lower trace
is the +/- 10 volts across the 2.5 ohm
resister. E = I x R and I = E/R.

In other words when the lower FET
turns on the current pulse in the coil flows
one way and when the lower FET turns off
the current in the coil flows the other way.
Duh!

This means we will have a total of 8 ignition
sparks for each leading spark plug. Groups
of two 10 degrees apart from 22 deg. BTDC
to 10 deg. ATDC. Up to 11,000 RPM or more.

Next step is get the high voltage power
supply and the stock Mazda 2nd gen coil
working. I'll be very surprised and disappointed
if this system does not significantly improve
the BSFC of the rotary.

Paul Lamar