while loop reboots

Thanks, DrAzzy. That makes sense. That also means I have to be careful about long computations.

Actually, I initially wrote my program (a pulse counter) using watches, but it was missing pulses, which is why I tried the "while" approach. What I just figured out is that the "watch" on ESP8266 needs fast edges, rather than levels to trigger. I sharpened the edge of the input pulses, and now I am not missing pulses.

Thanks again,
Dan