I have attached a file for the pin out of the Ignition cassette. Nr. 4
cylinder is the one closest to the connector. Pin number 1 is used for
monitoring the charge voltage to the capacitor (1/100 of the charge
voltage gives about 0-4V)
The voltage on the trigger pins is 12V and it triggers on the falling
flank when grounded (500mA peak). The trigger must at least be held
low for the discharge time of the coil which is about 500us. There
must be 2.5ms charge time between triggers to avoid damage to the
cassette. The recharge of the capacitor starts directly when the
trigger goes high again and the charge time is 2.5ms at 12V battery
voltage. It's important to minimize voltage drop in the harness as the
charge time will rapidly increase with lower voltage (3ms at 9V).
Charge voltage can be monitored the on pin 1.
The misfire signal is a square wave signal 0-12V. There are 2 lines
for this, one is for cyl. 1&2 and the other is cyl.3&4. SAAB also use
this signal during cranking to find the which cylinder is in the
compression stroke and which is in the exhaust stroke. The SAAB
Trionic trigs both partner cylinders until it can detect a combustion
in one of the cylinders, during this time these two coils get half
each of the stored energy in the Cap. You will have a signal some
microseconds after a trigger if you have a combustion. This signal is
only for combustion detect and has nothing to do with knock.