Power management concept...

Nils Faerber nils.faerber at kernelconcepts.de
Tue Apr 17 16:58:49 CEST 2007

This is maybe slightly off-topic concerning hardware but anyway, what is
the power management concept planed for the NEO?

I mean, will sleep/deep sleep be used?
If yes, in which conditions?
If not, what else?

The Nokia devices e.g. do AFAIK not use any deep sleep, they rather
suspend peripherals and clock down the CPU to a very low state. This
obviously gives them around 14 days of standby.

On the NEO we still need to power the GSM chipset for being able to
accept calls. Most of the rest could be suspended/turned off and the CPU
could go to sleep mode and the SDRAM could be put into self refresh.
This would save a lot of power.

But on the other hand it would increase the latency of device wake-up -
on incoming call or touchscreen activity. In both cases I guess a user
would expect the phone to ring almost at once when the call is signalled
from the modem or the screen be unblanked and lit when the screen is
What I am thinking of are also things like done on the (darn - is that
the only innovative example?) iPhone, i.e. a touchscreen guesture to
wake-up and unlock the device. If the NEO is sleeping such a guesture
recognition would require the CPU to wakeup on every touchscreen touch,
even the unintended ones. This could severely reduce battery life. But
if the CPU would be active all the time (but slow) anyway it would be

  nils faerber

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