CL1B power distribution

[pgf at laptop.org]

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
=---------------------
 paul fox, pgf at laptop.org