u-boot fix to charge empty battery

Werner Almesberger werner at openmoko.org
Thu Oct 9 14:10:38 CEST 2008

Philipp Hug wrote:
> * charging is only done when the LED is not active. Probably to make  
> measurement of power more accurate.
> -> Is this really necessary? It really slows down charging.

I linked this to the LED just for convenience. In theory, you could
probably make the non-charging interval much shorter.

You need to stop the charger when measuring, because a battery that's
missing or in cut-off would read as being at the float voltage (i.e.,
full) otherwise.

> * revisions <6 don't blink the LED when charging, this isn't optimal,  
> because can't see the difference between being switched off and charging  
> silently.

Yeah, I didn't enjoy doing that. You could probably get away by
briefly flashing the LED, and living on the extra juice stored in
capacitors. Not sure if it's worth the trouble, though.

> Does anyone know how much current the LED use on GTA02v5?

About 50mA, half of the total current budget in that situation.

- Werner

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