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Old 04-25-2017, 08:56 PM
Charixfox Charixfox is offline
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Pin 3 is the default because 1 and 2 are used for hardware serial on most Arduino boards and 3 is just the first available digital pin. 3 is not mandatory.

That being said, interrupts are disabled, which means they will not fire. They are not delayed, they are fully dropped.

However, as in any hardware interrupt situation, the source of the interrupt is important too. Edge or state? But this also adds complexity...

If the interrupt is on the edge, it will not fire at all unless it occurs when the interrupts are enabled. If it's on the state, it will fire repeatedly until the state is lost. So most interrupts are edge interrupts (the pin changes from high to low or vice versa, rather than the pin -is- high or low).

To be sure, I'd just track the pin state with a static, watch for a change, and then continue watching/ignoring until it changes again to reset.
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