Can't boot Freerunner without battery - Was: Re: unable to start up freerunner after batterie was full down

Steven ** montgoss+openmokocommunity at
Tue Jul 15 18:09:21 CEST 2008

I assume this is planned, but I'll go ahead an say it.

I think the Freerunner should have a software feature to detect when
the battery is critically low and shutdown.  Ideally, the boot process
would also check the battery and refuse to boot(or at least require
override) if the battery charge was below the critical mark.  This
would prevent the state where you have a dead battery and no way to
charge it.

Either this feature or the ability to boot from USB is a must for the
end-user software load.

I personally had no plans to buy extra batteries or external chargers.
 I would hate to have to should I lose track of my charge status and
screw myself.


On Mon, Jul 14, 2008 at 11:12 AM, Al Johnson
<openmoko at> wrote:
> The phone can't take >100mA from USB without asking, and the PMU enforces
> this. The AC PSU can supply more than this, as can most USB ports, but at
> this stage of the process the checks to see if this is available can't be
> done so we're limited to 100mA. When the old uBoot powered up the assorted
> chips the current would spike higher than 100mA which was fine with battery,
> but without battery the PMU would cut the power to stop violation of the USB
> 100mA limit. The new uBoot changes the power up sequence to try to keep the
> current below 100mA at all times. That's a rough outline anyway - full
> discussion in the kernel list archive.
> On Monday 14 July 2008, Steven ** wrote:
>> The battery can delivery more power than the AC USB adapter?
>> -Steven
>> On Mon, Jul 14, 2008 at 1:18 AM, Joerg Reisenweber <joerg at>
> wrote:
>> > Am Mo  14. Juli 2008 schrieb Steven **:
>> >> Perhaps it's been said before and I missed it...  But why can't the
>> >> Neo boot off USB power alone?
>> >
>> > Boils down to sth like powering up a whole town after blackout.
>> > All components drawing a spike of energy same moment, which USB can't
>> > deliver. ->next blackout.
>> > Werner's new U-boot extenuates this somewhat, but as much of this is
>> > inside PMU hardcoded, SW can't do much.
>> >
>> > /jOERG
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