Hi,

> Gennady Palitsky wrote:
> >
> > I am back with the question on PIC and power consumtion. I need to make
> > measurements with PIC every 5 minutes, keeeping power consumption to the
> > minimum between measurements. My first thought - to turn power to PIC
> > off and to turn it on by external timer (what is 50-100 uA by itself).
> > Does anybody know of better way to do it? And second - how can I keep
> > track of what PIC is doing if I power it off and don't use NVRAM?
>
> If the 5 minute period is flexible, the absolute minimum power can be
> achieved with a few CMOS gates and a low-drop regulator.
>
> Hook the low-drop on one of the gate outputs. Set up a slow charging
> cap on the input. This will switch the PIC on every time the cap charged
> up fully. You then switch the CMOS output off with an input coming from
> the PIC.
>
> You can drop from microamps to nanoamps this way. I've seen a wireless
> alarm keypad designed like this, and its 9V battery lasts for
> effectively the shelf life of such a battery.
>
I have another question regarding low voltage design.  I want to design a
battery operated circuit (3.3V) with a PIC controller.  My question is
how do you do the development?  You would obviously want to use a JW
(windowed) device, but as far as I could gather, the JW devices are only
rated for 5V (min 4.5V) usage.  I can run the circuit at 5V while
developing, but since it contains some analog components I cannot be 100%
sure that it will work at 3.3V as well.  Any suggestions?

Thanks,
Niki