Freerunner won't charge, and won't start anymore due to out of power

Mike Montour mail at mmontour.net
Tue Sep 2 18:36:21 CEST 2008


Alexander Frøyseth wrote:

> Does anyone know WHY it don't charge when it is off?
> My logic says that it is very important to have the option charge the 
> battery when it is flat.

I can't give you a simple answer. Charging is controlled by the PCF50633 
chip, based on configuration values that are written to it by u-boot, 
Linux, and userspace programs. Some of these settings are preserved 
across a power-cycle (the PCF50633 has a small backup battery that's 
also used to keep the RTC running) so the behavior at startup depends on 
the software that you used during your last session.

Another complication is that some Freerunners are capable of starting up 
without a battery while others are not (possibly due to different 
capacitor values on the internal power rails).

I can give a few hints:
- The current u-boot has a bug that means it will not properly charge 
from the wall charger. Try a USB cable into a PC instead.
- Try to boot into the NAND u-boot menu (hold power and then aux) and 
then select "power off". This may leave the device in a state were it 
will charge. Wait 15 minutes and then try to boot Linux.
- Try booting through NOR u-boot instead (hold aux and then power) with 
either the wall charger or a 500mA USB connection, then try booting Linux.
- If the device shuts off during one of the above attempts, let it sit 
for a few minutes and then try that same item once again

I've written some u-boot patches that improve low-battery handling. 
Anyone who's interested can take a look at the openmoko-kernel list for 
more details, but be warned that the code is not yet ready for general 
distribution (i.e. anyone who tests it does so entirely at his/her own 
risk).





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