XO 1.75 A3 ECOs

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These are recommended engineering change orders (ECOs) to the A3 prototype of the XO-1.75 laptop. This is NOT a list of changes from A3 to B1, that is located elsewhere.

SMBus Pullups

These correct a mistake omitting the pullup resistors for the SMBus between the EC and the battery charger. It has been done to all boards.

  • Add a 1.3K resistor between PR200 and +3.3VSUS (available at PD31, pin 2).
  • Add a 1.3K resistor between PR201 and +3.3VSUS.

External SD Power

This corrects a wiring error. It has been done to all boards.

  • Tie PQ64.2 to Q22.2

Audio Power

This corrects a wiring mistake (Trac ticket 10974).

  • Wire +3.3VA_AUDIO (U24.5) to +3.3V_AVDD (C218).

It has not been done to many boards.

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