CL1B power distribution

pgf at pgf at
Sat Apr 25 10:05:03 EDT 2009

smith wrote:
 > >>> 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.
 > > 
 > > Interesting point.  That would require extending the EC API, as they  
 > > go to an A/D
 > > not directly addressable by the main processor.
 > > 
 > >> Ideally updates could be frequent enough to pick up a waveform
 > >> from an unrectified power supply. (spare audio channel?)
 > Don't have much in the way of EC cycles available.  Don't have much EC 
 > ram left to cache values either.
 > I can make the readings available via EC commands but each command takes 
 > a few ms to complete and back to back commands will have a few ms of 
 > delay as well.  I'm guessing you might be able to get a 20ms update rate.
 > The best method would be to leave indexed IO enable and tell the EC to 
 > quit reading from the ports.  Then you could use indexed IO to read the 
 > AD registers directly.  I'm not sure what update speed you can get that 
 > way but it should be pretty fast.

i would think Measure would be more interested in (short-term) averages
of voltage and current than in seeing power supply noise.

(will an XO even run properly from an unrectified, or even
unfiltered, supply?)

 paul fox, pgf at

More information about the Devel mailing list