[Community] GTA04 - Power management improvements

Dr. H. Nikolaus Schaller hns at goldelico.com
Tue Jan 28 08:58:42 CET 2014


Am 28.01.2014 um 08:50 schrieb Hermann Schwärzler:

> Hello,
> 
> On 01/17/2014 11:32 AM, Dr. H. Nikolaus Schaller wrote:
>> 
>> Am 17.01.2014 um 10:56 schrieb Radek Polak:
> [...]
>>> I have no electrical skills, but i'd make sure:
>>> 
>>> 1/ when device is off it eats ~0 mA
>>> 2/ with just modem turned on ~3 mA
>>> 
>>> IIRC the values for 1/ and 2/ are currently very strange (somewhere
>>> around 20mA?).
>> 
>> Then your board must be broken, because we have made that sure 3 years
>> ago... It was one of the first steps when bringing up the boards and
>> testing if the components are the right ones.
>> 
>> All measurements I have done show
>> 
>> 1/ ~0mA
>> 2/ between 3 and 100 mA (100mA temporarily if there is some
>> communication with the base station) - this current depends heavily on
>> antenna position and distance to base station
>> 
>> But I can test it again if you think it is not so.
> 
> Hmm. When I measure power-usage by reading the charge-values of the
> battery I get the following:
> 
> Over night
> 1) a switched-off device uses 288.1 mAh over a time of  9:33 hours;
>   a switch-off-on cycle uses about 7 mAh so the net usage is 281.1 mAh
>   equivalent to an average current of 29.4 mA.

> 2) a suspended device uses 195.3 mAh over a time of 9:20 hours
>   i.e. an average current of 20.9 mA
> 
> This is more or less the 20 mA Radek is seeing.
> So both our devices are broken?
> Or is my test-setting "broken"?

How do you "switch off"?

Did you make sure that the modem is powered off as well?

Both, APU and Modem have independent power supply and
a pure "poweroff" of the APU does leave the Modem active
(so that it can potentially wake up the APU).

The correct way to turn the modem off is a script like this:

http://git.goldelico.com/?p=gta04-rootfs.git;a=blob;f=debian/config/root/wwan-off;h=87efafcf5f38a80b4e4fa074b7e5c31c2f7b635a;hb=HEAD

BR,
Nikolaus






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