Vincent, I am developing something like that at the company, a device that runs
for just one second and goes to a complete power shut-off for 299 seconds (300 s
econds cycle).
After lots of research we decided to use an external circuit that shuts off all
the power to the main chips, allowing power only to a RTC and the power control
(74hct00 + FET
transistor). The RTC alarms the power control to "powers up" the rest.

It works pretty nice, the board consumes 11 ma during 1 sec and only 5 micro Amp
s in "off" state.  The average current at this circuit is only 41uA/h, so a pack
 of 4 x AA Cadnica
NiCad cells (800 ma x 4.8V) can keep this operating for more than 18 thousand ho
urs, almost 800 days.

And this is not good enough, because we are using an Atmel 2051 that consumes al
most ma just for the processor.  Changing to a PIC device we could keep the same
 power autonomy with
only 2 x AA regular alkaline cells.  We use a charge pump chip to step up and re
gulate the necessary 5 Vdc to a crazy ADC 24 bits on the board that needs it is
not produced for low
voltage.

                "Long Live to the Batteries!!!"

                                or

           "The POWER will be with you...forever!"


------------------------------------
Wagner Lipnhasrki - Orlando, FLorida
UST Research Inc. - http://ustr.net
------------------------------------

Vincent Deno wrote:
>
> Thanks for all of your suggestions.  I think my best bet is to set the
> postscalar to it's max and clear out the WDT periodically.  It's not
> exactly how I wanted to do it, but work-arounds are sometimes necessary.
>
> I don't mean to ask a stupid question but...  On mny of these threads, I
> (and believe almost everyone) has thoughts on each problem others are
> having.  I refrain from posting a reply if I'm basically regurgitating
> similar thoughts of another without significant additional input.  I'm
> just making sure this is the basic belief of most on the list or if I
> should be spending much more time replying.
>
> Thanks Again,
> Vincent Deno