Zero cross detect - switching audio

[HankMcSpank]

Just saw your edit, If your main is really doing nothing, skip the ISR all together and just wait in main for the switch press.

ok, perhaps what I should have said(!), is that when the switch is pressed, it will supercede everything else that might/might not be going on in the (low priority stuff) main ...therefore once in the Switch IOC interrupt happens, I can hang out in the interrupt routine for as long as needs be! (the main will just have to wait!)

I don't remember off hand what the answer is, but DT_INT ASM type takes only a few cycles (I think) to get in.

As mentioned, I have no way of gauging this (I'm in "I think" territory too!), so when I seek something as time critical as catching a near zero cross, to my mind, I reckon it's better to be in there already & tracking the comparator output with a while/wend, then outside not knowing how long it'll take to get in!