This week in the life of CL1B

[John Watlington]

A small number of XO 1.5 B1 boards have arrived and are in hardware  
testing.
The Quanta team, working in secret, decided that the B-phase risk was
too high to do in a single run and built a B1 motherboard.  The  
availability
of plastic for B-phase was delayed due to complications from minor  
modifications
to tooling still being using for production, providing the opportunity.

A small number of these B1 motherboards were fabricated in Shanghai, and
simultaneously shipped to both Taipei and Cambridge.  These boards
have a number of problems, but allow us to test the fixes applied for
suspend/resume and SD interface problems.  They both seem to be fine
after a few days of testing on 14 bare motherboards.   Thanks to the  
efforts
of Paul, Mitch, and Richard, we have OFW and Linux which support
these prototypes.   More details about the motherboards are available  
at:
http://wiki.laptop.org/go/XO_1.5_B1

We have to fix a number of problems, make schematic and board changes,
and approve the B2 board layout by next Wednesday night (EDT) in order
to stay on schedule.

I spent a day last week working on a new interface to Tinderbox (as well
as adding twenty more power measurements channels, diggging into
where +2.5V and +5VSUS was going...)   The new interface, illustrated  
at:
http://dev.laptop.org/~wad/xo1.5pwr/test3.html
presents the Tinderbox measurements in the context of the power  
distribution
tree, without having to import them into a spreadsheet (the previous  
approach).

Richard has long suspected that the inductor value in the XO backlight
is too low.  I finally got around to measuring the efficiency of the  
backlight
using different inductor values, and we can improve it from around 88%
to 95% by changing the value.   This saves upwards of 50 mW, even in
suspend!  The table of measurements is available at:
http://dev.laptop.org/~wad/xo1.5pwr/backlight.html

Cheers,
wad