New XO 1.5 firmware with MPPT. Please test!

Ismael Schinca ischinca at
Wed Apr 6 15:18:50 EDT 2011

Hey Richard! Here's a log from a partial battery charge in the following

- XO 1.5HS using the firmware you sent
- Connected to an unregulated 10W panel
- Using the script rtcwake-log you sent I think it was from december last
- The first couple hours the panel had no direct sunlight

Unfortunately, since the panel was a sample I couldn't modify it to measure
actual current or voltage from the panel.

Quick comments:
- The XO charging light was always on with the panel conected, even with
very low light.
- When the battery was full, the XO started doing that buzzing sound, like
when it works with a low voltage, only this time it was louder than in that
situation. I'm guessing maybe as the battery wasn't charging the panel
reached close to open circuit voltage and there was some pretty heavy
regulation going on?

Just from this one, I would say that the firmware worked great! It's a pitty
I cannot verify with hard numbers the MPPT function.


P.S. No problems upgrading the firmware with this version

2011/4/5 Richard A. Smith <richard at>

> On 04/04/2011 06:22 PM, Richard A. Smith wrote:
> > There is one known problem. On your very first flash you might lose the
> > keyboard/mouse. You can prevent this by doing a full power cycle of the
> > EC. ie no ext power and no battery.
> New version:
> This one hopefully fixes the keyboard issues.  Anyone who experienced
> that problem please reflash your previous firmware and then flash in
> this new one.
> Thanks.
> --
> Richard A. Smith  <richard at>
> One Laptop per Child
> _______________________________________________
> Devel mailing list
> Devel at

Ismael Schinca
Centro Ceibal - Depto. T├ęcnico - I+D
Avda. Italia 6201 - Edificio Los Ceibos
Montevideo - Uruguay.
Tel.: 2601 57 73 Int. 2232
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