> Bob Blick wrote:
> > 3 * 1.5 = 4.5 volts. Adequate for one-off "hobby" projects at 20MHz.
> 
> I know it's a hobby project but I'm doing it with the aspiration of 
> actually making a marketable product, which is why I'm sticking to the 
> limits of spec sheets and so forth.
> 
> If I need 4 AA batteries, I'll use 4 AA batteries.
> 
> > It
> > will be close to 5 volts with fresh batteries and you'll have to see how
> > low you can go. A good reason to read the page on the brownout detect in
> > the PIC(leave it off for now).
> >   
> 
> What does "brownout detect" do? Does it shut down the uC if the supply 
> voltage drops below a certain threshold?

RTFM. ;)  Seriously, read section 14.  It does a body good.

Short and flip answer is the BOR will put the PIC into reset and hold it there until the Vdd level raises back above a certain trip point, stays there and also conforms to some risetime stuff.  Some interaction with the POR too.  And I think, please consult the data sheet to confirm, that you can read a status register after reset and determine the reason for the last reset.  Possibly useful in error recovery situations.

And one more thing, again, a data sheet check and schematic (which I don't have to reference) is if the comparator mode of the 16F887 could be used as a voltage monitor so that you can get an early warning to pending battery failure.  Save game and all that jazz.

Rob
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