CL1B power distribution

Albert Cahalan acahalan at
Sat Apr 25 01:06:12 EDT 2009

John Watlington writes:

> - The SD slot and USB ports may be powered in suspend
>      This is "just in case" some SD cards or USB devices don't handle
> being suspended
>      aggressively.   We will support laptop wakeup on interrupt from any
>      of these ports (SD or USB).   Under software control they may
> also be powered
>      down during suspend.

There is value in making this per-port for the USB.

> - The audio codec remains partially powered in suspend
>      This is in order to support "wakeup on jack insertion".  The codec
>      may be placed in a very low power state during suspend.

I would have expected power to be optional. The software doesn't
always need to use this component during the run state.

> Additional changes from Gen 1 include the ability to both measure
> DC input current and VIN voltage, as well as EC control over the
> current drawn from the DC input. The intent was to better support
> charging directly from solar panels.

I hope that this will be available to activities like Measure.

Ideally updates could be frequent enough to pick up a waveform
from an unrectified power supply. (spare audio channel?)

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