Guy Sirton wrote:
> 
> Hi,
> 
> Vince Deno wrote:
> > > Can anyone suggest a way to take advantage of the power-saving
> > > capabilities (killing the OSC) without having to worry about generating a
> > > false WDT reset?  Any suggestions regarding this, or any other
> > > power-saving functionality would be greatly appreciated.
> 
> You could use an external watchdog or RTC chip to wake you up on a
> pin change.  Generally speaking lower voltage, lower clock rate and
> lower duty cycle will give better power.  If you told me more about
> your application I could possibly make some suggestions.
> 
> You should remember the watchdog timer eats some power too (around
> 9uA typ. if I have the right datasheet open).
> Another issue with PIC's is the internal pull-ups, make sure no
> current is flowing through them.  Don't leave any tri-state inputs
> open.  Power switching is another way to save power, if you have
> devices in your design that are not used all the time you could
> switch them off with a MOSFET (make sure no current will flow through
> them when they are off, e.g. through the protection diodes).
> The latest edition of Art of Electronics has a chapter on low power
> design, well worth reading.

An approach that has been discussed before, is to use 
a 4060 clock chip and to tap the PIC closk from 
different points.

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