Haha yeah funny because I've been working on the CDI thing too, I was pretty close back in 2015 in Texas where I was working with uC engineers all day and they could answer all my dumb questions. I had actually gotten the timer interrupt working and the scr circuit triggering the coil but I realized that it wasn't going to work the way I was planning on doing it. I'm building a speeduino for my Subaru slash future Ford truck project, there are some real smart folks in that community and they have made some bare Bones units that could be a basis for an ignition only unit. There was also a guy on a Opel forum that built a really nice simple ignition controller that I was trying to contact. Maybe if we put together a real project he would be interested in helping.
This temp display logger was just something I need for a part that I'm designing but these M0 chips are so powerful now that it really wouldn't take much to do all the sensors you could want and still have plenty of CPU left to run a CDI, display, whatever. I don't know what the timer architecture is like on these compared to the traditional a32p stuff, but I'm sure someone has figured it out.