[Tinyos-devel] more bugging about current consumption on MicaZ in tinyos-2.x

[Razvan Musaloiu-E.]

Hi!

On Wed, 19 Jul 2006, Philip Levis wrote:

> On Jul 19, 2006, at 9:31 AM, Razvan Musaloiu-E. wrote:
>
> > Hi!
> >
> > On Wed, 19 Jul 2006, Eric Weddington wrote:
> >
> >> Philip Levis wrote:
> >>
> >>>
> >>> It's very interesting, though, that the deep sleep state of the
> >>> atmega128 is in practice so much lower than what the data sheets claim
> >>> (and what a lot of papers have used as the basis for  estimates).  It's
> >>> also much lower than what Joe reported measuring  (e.g., we're 40% of
> >>> what he said is the lowest he's heard reported).
> >
> > The specs for Atmega128L ([1] page 323) indicate a typical <5uA in
> > Power Down for Vcc = 3V.
>
> Yeah. Joe's comment was that 5 is the bottom of the range, though.
> Also, if you look at the Telos paper, it documents the micaZ power
> draw at 27uA for just the RTC. That's a factor of 10 different than
> what we've measured.

Just for reference I'd like to mention that Xbow indicates a 0.01mA on
page 17 in their MPR-MIB User Manual:
	http://www.xbow.com/Support/Support_pdf_files/MPR-MIB_Series_Users_Manual.pdf
To add more to the confusion, on the example presented on the next page
they use a 8uA value.

>
> >
> >>> I'd really love to see what the msp430 pulls; I would not be surprised
> >>> if it is similarly lower (e.g., < 0.5uA). But measuring it  would be
> >>> great. If only my Ubuntu drivers weren't so cranky...
> >>
> >> I would also be interested in a side-by-side comparison of this data.
> >
> > Here are some tests on 2 Telos Sky:
> >
> > 	ACTIVE 1.83mA  1.83mA
> > 	LPM0   0.15mA  0.15mA
> > 	LPM1   0.15mA  0.15mA
> > 	LPM2   26.2uA  26.4uA
> > 	LPM3    7.0uA   7.1uA
> > 	LPM4    7.0uA   7.1uA
> >
> > Running basestation disconnected from the PC and no packets
> > received I got 20.01mA and 20.17mA.
> >
> > Note: the input voltage was 3V and I used the same Extech multimeter as
> > before.
> >
> > It would be great if Phil or Joe could post what values they got.
>
> That's interesting. It looks like the micaZ draws less current when
> just running an RTC: I measured 3-5uA, with an average of 4uA. Of
> course, it is handling interrupts more often, and its wakeup time is
> longer, so the integral is probably larger. Measuring that with an
> oscilloscope would be very useful. Still, these values seem to be
> quite different than what has been reported. Based on your
> experiences, I think it's very possible that some of those
> measurements were from "bad" micaZs. To put the data side by side:
>
> MicaZ MCU active draw: ~3.6mA
> Telos MCU active draw: 1.83mA
>
> MicaZ deep sleep draw: 3-5uA
> Telos deep sleep draw: 7uA
>
> You are using a controlled 3V input? That is what I have been doing
> as well.

I'm using a BK Precision 1630 and the measured voltage is 3.00V.

--
Razvan ME