On Thursday, 9 March 2017 23:16:15 GMT Ralph Corderoy wrote:
> What
> https://docs.python.org/2.7/reference/simple_stmts.html#the-global-statement
> is saying is that you only need to point out global variables with `global'
> when you want to write to them, not just read them. And using `global' is
> an indication to the reader that you intend to write, so it isn't used just
> to point out a variable is global as that misleads. (The reader can
> probably recognise a global that's only being read due to its longer name.)
OK. Thanks. I picked up the idea from a bit of code that I saw, but didn't
realise the distinction.
> I echo Patrick's question; that seems inconsistent with there only
> being one line printed in the other email.
>
> > > Are the callbacks defined to be edge triggered, so on the switch's
> > > transition from off to on?
Yes. the ARG is GPIO.RISING. I don't believe that the Library supports level
triggering and I wouldn't want that anyway.
> You didn't mention whether the Python library says what triggers the
> callback. Have you tried moving the switch from off to on and holding
> it there against the spring and observe what happens? Does the callback
> run once with one line printed? Once it's all finished, let the switch
> spring back to off; does it call the callback again?
Se my response to Patrick.
--
Terry Coles
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