#4143 NORM Never A: EC does not know external supply voltage

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#4143: EC does not know external supply voltage
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 Reporter:  frief                                                 |       Owner:  jg            
     Type:  enhancement                                           |      Status:  new           
 Priority:  normal                                                |   Milestone:  Never Assigned
Component:  distro                                                |     Version:                
 Keywords:  supply, power, EC, charging, embedded controler, ADC  |    Verified:  0             
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 Measuring external power would require not more than
 2 resistors (and eventually one ceramic condensator).

 According to:
 http://wiki.laptop.org/go/Ec_specification#EC_IO_Pinout
 Pin 40 (GPIOAD2) of the embedded controler is not used on a C1.

 This pin should be connected by a resistor divider to the input
 voltage after the input protection (according to Tinderbox_B3.pdf
 eventually the net VA2 could be used).

 Time constant of the RC lowpass could be in the 1 ms range so a
 breakdown of the input voltage (when f.e. (quick) charging mode
 is switched on) can be detected early.
 At least a few XOs will operate on weak or underdimensioned
 supplies so input supply voltage should not be neglected.

 (Sorry if this is a duplicate, I asked elsewhere but so far
 got no positive response.)

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