Steve, I have hardware only systems out there in the field, used every day, where a latch is connected to a key maybe 100 metres away, through site wiring. There are optos, CR's and so on making sure that such stuff doesn't get through. If they were having that kind of intermittent problem, believe me, I'd be getting told about it!

Even if the switch was in the same box as the micro, I would tend to use at least a simple CR, rather than a raw high impedance digital input.

Let's say we are talking about DEBOUNCING a switch - not applying LP filtering as well.

(IF the brief is also to apply LP filtering, OK. Fair enough. But it is not correct to assume that that is always acceptable - consider the app. There ARE some cases where the delay might be undesirable.)

So provided that I am happy not to implement LP filtering in software, is there any other reason for not doing it as I describe?