TWRMCF51JGUM
TWR-MCF51JG Tower Module User's Manual
Page 9 of 21
Figure 5.
32 KHz Oscillator Input
2.3
System Power
When installed into a Tower System, the TWR-MCF51JG can be powered from either an on-board
source or from another source in the assembled Tower System.
In stand-alone operation, the main power source for the TWR-MCF51JG module is derived from the
5.0V input from either the OSBDM USB mini-B connector (
J14
), the MCF51JG USB micro-AB connector
(
J8
), or the EzPort header (J16
)
when a shunt is placed on jumper
J15
. Two low-dropout regulators
provide 3.3V and 2.0V
supplies from the 5.0V input voltage. Additionally, the 3.3V regulator built into
the MCF51JG can be selected. All the user selectable options can be configured using two headers,
J9
and
J10
.
The
J10
header is used to select the power source that is supplied to one of the three possible voltage
regulators. The
J11
header is used to select the regulated board power source. Refer to Table 1 and
Table 2 for details.
Table 1.
J10, Regulator Power Source Selection
J10 Shunt Setting
Description
1
2
7
8
1-2
Power from the OSBDM interface (
J14
) supplied to the on-
board voltage regulators. This is a
default
setting
.
1
2
7
8
5-6
Power from the MCF51JG USB device interface (
J8
) supplied
to the MCF51JG on-chip regulator. This is a
default
setting
.