The AT32UC3C-EK can be powered from four different sources: 2x USB mini AB plug (5V input): labeled "USB USER" (J21) and "USB VCP" (J27) and 2x external power supply J1 jack connector or the J2 2-pins headers (DC 12V ±10%).
The AT32UC3C-EK will automatically switch to the more accurate power source if it senses voltage on it (external power supply is defined as the more accurate power source, then VBUS from "USB VCP" and the less accurate power source is VBUS from "USB USER").
These inputs go through an external 3.3V switch mode regulator which delivers supplies to the rest of the board with a 3.3V voltage.
The power indicator LED green D3, labeled "POWER", indicates if the 3.3V from the external regulator is present.
Refer to Configurations and Test Points for a description of the possible hardware configurations of the power supply block.
