Hi Dave,

> That driver responds only to falling edges on the GPIO line, right?  I'm
> somewhat surprised that it would do this - it would be more generally
> useful to respond to a falling or rising edge on the GPIO I would have
> thought, but I guess it is just an example.

Yes. The assumption was that the input is pulled high, and closing the
switch connects the input to ground.

Could you please elaborate about the part about input being pulled high, for someone who does not have as much electronics knowledge?  Thanks -