firmware Q3a35e

Richard A. Smith richard at
Mon Apr 5 17:37:03 EDT 2010

I have an 1.5 pre-release firmware I'd like some wider testing on. 
Please install this on your 1.5 and run some charge/discharge cycles on 
your battery.

There's a few minor changes in OFW from this and q3a35 mostly the 
addition of some commands that let you enable and disable EC MPPT and 
observe whats going on.

The real changes are in the EC code.  The introduction of MPPT [1] into 
the firmware required deep structural changes to the battery & 1-wire code.

While I was ripping everything apart I also implemented some of the more 
invasive changes I had planned.

If I got everything right you should see zero difference between battery 
operation on a35 and a35e except that some bugs are fixed.

I've been running this code on all of my test machines for the past 2 
weeks churning through lots of charge/discharge cycles with no problems, 
but I won't be surprised if there's still a few regressions waiting to 

Although this firmware has the ability to do MPPT when connected to a 
solar panel its disabled by default.  The reasons for that are:

1) I'm the only person who as a XO properly modified for MPPT to work.
2) Its not quite ready yet.  It backs off the power sometimes when it 
should not.

The point of this pre-release is to get some wider testing of the new 
battery code and not MPPT.  I'll announce when the MPPT stuff is ready.



Richard A. Smith  <richard at>
One Laptop per Child

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