BDS_E
Boundary scan enable.
Default state is open.
BAT/EXT
This jumper controls the input power supply for the VBAT
pin.
If 1-2 are shorted, the external battery is connected to
the
VBAT pin.
If 2-3 are shorted, the VBAT pin is supplied by the
on-
board +3.3V supply.
Default state is 2-3 shorted.
EXT/USB_D
This jumper controls 3.3V power supply for the board.
If 1-2 are shorted, the external power (from the PWR
jack and after the +5V voltage regulator) is input to
the
+3.3V voltage regulator and supplies the board.
If 2-3 are shorted, the USB device pr5V to the
+3.3V
voltage regulator and supplies the board.
Default state is 1-2 shorted.
