On Sat, 9 Mar 2002, Bob Ammerman wrote:

> Turning on the internal pullups should _not_ result in such a jump in
> current draw, unless one or more of the pins is connected via a not very
> large resistance to ground.

Well, the data sheet says max 400uA.  It doesn't specifically say total or
per pin.  Even 400uA is a little more than I'd like to see, though.
We're talking about AA batteries, and I'd like to not see them drained.
Yeah, sure, I *could* just add a SPST slide power switch, but where's the
fun in that?  Heck, that'd be like switching AC with a relay!  8-D

I guess it's kind of an academic exercise, really.  This is a one-off, but
I'm lookig at it from a commercial perspective to see how low I could get
the per-unit cost in production and still have it operate reliably.  Old
habits die hard, I guess.  Not just parts cost, but board space and
assembly cost too...  the ideal design is one component.  I've got this
one down to one PIC, one resistor, one NPN transistor and an optional (but
recommended) cap.

> Is one of the other pins, beside the one you are trying to use for wakeup,
> pulling a pin down?

I suspect my GP1 pin is flaky on the -JW part I have.  When I set it as a
HI output and leave GP1 as an open input the current consumption in sleep
mode goes WAY, WAY down.  Below where my meter can read it, which is low
enough for me.  I may have to break down and replace my EPROM chip.  It's
spent enough time in the eraser it's got a nice tan though!  ;)

Dale

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics