Seems like things are working properly, just maybe bad settings.

Try 4000 uS for MSD_Delay and 3 start sparks. If you assume that you're starting around 200 RPM then 4000 uS will fire the first spark at 5 deg. BTDC the next at TDC and the last at 5 deg ATDC.
As for the rest, I don't know how much use the multispark is going to be.

The values I got from my test code and the ones that seem to look right when testing the actual program code don't jive.
Here's what I think is happening... In my test code it throws around a 1000 sparks, and I got sparks to work every 66 uS. That's about the max speed the SCR can switch. I think the fast switch times were not letting the capacitor charge up, thus making the SCR able to switch faster. But in the real application the capacitor is charged, so it takes longer to discharge, which keeps the SCR on longer, thus missing the fast rhythm of the firing.

In any case, 66 uS seems to work for long bursts where the capacitor doesn't have time to fully charge, but not for short bursts where each firing may take more time to recycle.

More testing to find the best settings is needed. I can't see individual sparks at these ultra fast speeds, so I can't really tell what's going on. 4000 uS seemed to produce a good spark where I could tell for sure it was firing right. But that's pretty slow and will only work at low starting RPMs.

So for now, I would use 4000 uS for the delay, throw 3 start sparks, maybe 2 for MSD_Low_Spark, and just one for MSD_Spark.

Anyone can help this project out and work on tuning these values. Right now I don't really have the test gear to figure out much more than I already have. Someone who has a spinning test wheel apparatus should try adjusting these settings and find the ranges that work!


-Jake