#4143 NORM Gen2: EC does not know external supply voltage

[Zarro Boogs per Child]

#4143: EC does not know external supply voltage
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  Reporter:  frief        |       Owner:  mlj                                                 
      Type:  enhancement  |      Status:  new                                                 
  Priority:  normal       |   Milestone:  Gen2                                                
 Component:  hardware     |     Version:                                                      
Resolution:               |    Keywords:  supply, power, EC, charging, embedded controler, ADC
  Verified:  0            |  
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Comment(by frief):

 > What are you trying to achieve here?

 - an XO connected to a Pb battery could be told: do not discharge the Pb
 below xx Volt

 - an XO in a classroom situation could complain: I'm seeing a voltage of
 xx Volt while
   others have xx+y Volt, is it getting warm somewhere?

 - or (maybe for remotely checking classroom cabling), a source impedance
 of the supply
   voltage of 0.y Ohm is seen at the last place, expect problems when
 connecting more
   that z XOs. (Impedance could be measured by the voltage drop when
 switchting
   to high speed charging)

 - or eventually the XO could be told: there is an external (weak) supply
 (partly
   illuminated solar panel), please try to operate it near the optimum
 efficiency
   point (by adjusting the duty cycle of the charge controler (don't know
 whether
   the charge controler would like that))

 - or if the XO is connected to a solar panel it could tell: I see an
 immediate
   voltage breakdown of x Volt if I switch on charging for 10 ms.
   If a condensator of y uF would be added I, the solar panel and the radio
   connected to the solar panel would play together more nicely.

 - Or (possibly after calibration) you could use it as a voltmeter (without
   needing external circuitry).

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Ticket URL: <https://dev.laptop.org/ticket/4143#comment:3>
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