delayMicroseconds(0) = 16383µs

JimEli:
Sidetrack:

Why is anyone calling delayMicroseconds(0) in the first place?

Because sometimes 1ms is WAY too long of a delay.

I have a glcd library where even 1us is WAY too long.

For that I use a cycle accurate delay routine that self adjust based on
the MCU clock rate.

--- bill