circuit for sync trigger, efi on an MC-1

[Orin Eman]

> If I use an "AND" gate IC, it's output is only "high" when both inputs
> are "high".  So, the timing reference pin passes the sensor, and
> nothing happens, unless the hall sensor signal is "also" present.
> In operation, the hall sensor signal will be present before and after
> the timing pin signal, since it's duration is longer.  The actual signal
> sent to the ecu will be the "high" output of the IC.

Although an 'and' gate is a step in the right direction, you have
two problems.  First, the hall signal is active low - you would need
an inverter first - not a biggie and second, signal conditioning of
the timing pin signal - a biggie.  You can't do it with one chip.
You would need at least 3.  A 7400 (quad NAND) gate, an op-amp and
a voltage regulator.  Use one NAND gate to invert the hall signal.
Another to NAND the hall signal and conditioned timing pin signal together
and finally another to invert the result if necessary.  Then you have
the timing pin signal to condition.  The schematic is out on the
diy-efi.org ftp site or you can wire up a MAC11 and pull the signal
out of the MAC11... you'd just have to follow the schematic to find
the signal.

Orin.