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A comment on Nubsio GPIO API – A Windows USB interface for controlling external devices. Parent comment

Re:Nubsio GPIO API – A Windows USB interface for controlling... by Matthias247 on Monday April 03, 2017 @02:27AM (#14020958)
it actually is, as long as your polling interval is deterministic and meets the requirements of your target application (polling interval < state change interval).

If you look at real hardware (or FPGAs) they will basically do polling: The input gets sampled at each clock cycle and will then get processed. And hardware is definitely realtime :)

The downside of polling is that you burn CPU resources when actually nothing happens. Interrupt driven designs help there.

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Re:Nubsio GPIO API – A Windows USB interface for controlling... by sokoloff on Monday April 03, 2017 @09:31AM (#14022584)
> If you look at real hardware (or FPGAs) they will basically do polling: The input gets sampled at each clock cycle and will then get processed. And hardware is definitely realtime :)

Smiley noted; I think we can agree that "polling at 10s of MHz on an input pin" becomes something quite different than "polling at 10s of kHz on the other side of a USB link".

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Re:Nubsio GPIO API – A Windows USB interface for controlling... by jononor on Monday April 03, 2017 @10:48AM (#14023113)
USB link to a PC with a general-purpose OS likely kills the determinism requirement.
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