> > - Create an input voltage monitor that provide a logic output when the
input
> > power supply comes out of spec in a way that you have determined should
> > trigger shutdown.

> Or don't reinvent the wheel and *buy* on instead. There are many different
> "supply-voltage supervisors" from most IC manyfacturers.

No. That's detail :-)
My intention was to provide a clear outline of the core task - not the
specifics of the solution.
Too many tasks get bogged down when people attempt to include part of the
answer they want to get in the question they are trying to ask.

That said, the manner of doing it that you suggest is almost certainly what
I would do in the circumstances. But suggesting it "up front" in the
specification may have steered him down a sub-optimal path.
I know all about those :-)



        Russell McMahon


(Yes, I know my answer was partly detailed solution in that I said to use
interrupts. Maybe that should have been "utilise the processors resources in
as prompt a manner as possible to ... " ;-) )

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