TWRMCF51JGUM
TWR-MCF51JG Tower Module User's Manual
Page 11 of 21
Table 2.
J9, Board Power Source Selection
J9 Shunt Setting
Description
1
2
7
8
3-5
Board power is supplied by the 3.3V on-board (external)
regulator. This is the
default
setting
.
1
2
7
8
5-7
Board power is supplied by the 2.0V on-board (external)
regulator.
1
2
7
8
1-2
Board power is supplied by the 3.3V MCF51JG on-chip
(internal) regulator.
1
2
7
8
1-3
5-7
Power from the 3.3V MCF51JG on-chip (internal) regulator is
supplied to the 3.3V on-board (external) regulator. Board
power is supplied by the 2.0V on-board (external) regulator.
Note: Take care not to install a shunt on J10 pins 1-2 when J9
is in this configuration. It is recommended to remove the
shunt from J10 1-2 and use it on J9 for this setting.
1
2
7
8
+
―
―
An external battery or other alternate source can be
connected to pins 5 (positive) and 6 (negative, ground).
The 3.3V or
2.0V power supplied to the MCU is routed through a jumper,
J12
. The jumper shunt can be
removed to allow for either (1) selecting the source of the MCU supply voltage or (2) the measurement
of power consumed by the MCU.
Table 3.
J12, Board Power Source Selection
J12 Shunt Setting
Description
3-5
MCU power is supplied by the board power source selection
jumper (
J9
). This is the
default
setting
.
5-7
MCU power is supplied by the 3.3V MCF51JG on-chip
(internal) regulator. Use this jumper setting if it is desired to
power only the MCU with the on-chip (internal) regulator and
not the rest of the board.