Power leakage: save 40mW by turning GSM on

Rask Ingemann Lambertsen rask at sygehus.dk
Sun Feb 22 19:44:58 CET 2009

On Tue, Feb 17, 2009 at 06:50:59AM -0300, Werner Almesberger wrote:
> Rask Ingemann Lambertsen wrote:
> >    Given that power consumption was basicly the same 8,32 mW before and after
> > the AT at POFF command, what exactly is that command supposed to do?
> That's funny, though.

   No, it's not, because I posted under my real name. The first two major
blunders in that posting are:

   1) Not setting the serial port speed. 
   2) Not waking up the modem from deep sleep before sending AT at POFF.

   For lack of a brown paper hat, I'm wearing the box that my Neo shipped

   Today, trying to hunt down a 13.8 mA current leak directly from the
battery, I cursed mickeyterm, echo, serial ports and modems in general
several times for sending every other command to a blackhole instead of to
the AT command interpreter. But in the end, I realized that the modem powers
up with deep sleep enabled, so after a few seconds of AT command inactivity,
it will go to sleep and not see the next command sent.

[AT at POFF]
> It tells the PMU of the GSM subsystem to
> shut down, similar to how we power off the main system (PMU state
> "Standby", not to be confused with CPU suspend.)

   In particular, is it supposed to undo the effects of AT+CFUN=1 (which
will turn on receiver, transmitter and everything else needed for full
GSM functionality)?

Rask Ingemann Lambertsen
Danish law requires addresses in e-mail to be logged and stored for a year

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