Just wondering if anyone happens to have put their ignition signal on a scope / knows what it looks like. If so I have a couple of questions -

1) I am assuming the pcm ignition module handles the dwell control - so the signal from the pcm to the ignition module is just a square wave, and the ignitor triggers off what, the rising edge?

So assuming I intercepted the signal between the pcm and ignition module I don't need to worry too much about the Ton time (again, assuming the pcm doesn't do dwell control, but the ignition module does).


2) With an 8 cylinder ignition I am going to see RPM / 15 ignition events per second ? So rougly a 60-400Hz signal (700-6000 rpm)?


3) Are there any discrete components that would let me phase shift in the negative the rpm waveform in response to an input (voltage/frequency/current, etc.) For example in response to a varying voltage input I could achieve a larger negative delay (timing retard) for a larger given voltage input?

Or am I going to need to look at a uC to do that? I have an atmel SDK500, I just need to take the time to learn how to program it - and I have the rest of my circuit mapped out in discrete components except for that part.


4) Any other gotcha's, etc. I need to look out for trying to get a timing retard on the ignition pulse circuit (I guess EMI is an issue under the hood, etc.)


Thanks,
Chris Bennight