D E M O A C U S E R G U I D E
A P R I L 1 0 , 2 0 0 8
9
Figure 3: PWR_SEL Option Header
PWR_SEL
• • •
Selects input voltage from POWER connector
BDM
VR1
NOTE: The VR1 input is connected to the regulator at VR2.
This is an error in the board silkscreen.
PWR_SEL
• • •
Selects input voltage from the integrated BDM
BDM
VR1
NOTE:
The voltage regulator reference designator at the PWR_SEL option header does not
match the reference designator of the voltage regulator.
VX_EN Option Header
The VX_EN option header is a 2-pin jumper that connects the target-board voltage rail to IO
connector position J1-1. IO connector position J1-3 connects directly to the ground plane.
This input requires a reg5.0V voltage source. This power input is decoupled to mini-
mize noise input but is not regulated. Also, no protection is applied on this input and damage
to the target board may result if over-driven. Do not attempt to power the target board through
this connector while also applying power through the PWR connector as damage to the board
may result.
Power may be sourced to off-board circuitry through the MCU_PORT. The current limitation of
the on-board regulator must be considered when attempting to source power to external cir-
cuitry. Excessive current drain may damage the target board or the on-board regulator. The
figure below shows the VX_EN option header connections.
Figure 4: VX_EN Option Header
ON
Enable power connection to connector J1
VX_EN
▪
▪
OFF
Disable power connection to connector J1
VX_EN
CAUTION:
Do not apply power to connector J1 while also sourcing power from either the
PWR connector. Damage to the board may result.
NOTE
: Do not exceed available current supply from on-board regulator when sourcing power
through connector J1 to external circuitry.
MCU Power
Each power input is routed through an option header. The option header is not installed in
default configurations and a cut-trace on each power input provides default connections. To