8 Freescale Semiconductor
Power
Power is supplied to the module through a 2.0mm barrel connector at location PWR for stand-
alone operation. The module may also be powered through connector J1 when connected to
the PBMCUSLK. Power may be sourced off-module through connector J1 to external circuitry.
Power routing on the module is determined by the PWR_SEL jumper.
PWR
The PWR connector accepts a 2.1mm, center-positive, barrel plug that allows the module to be
powered from a wall-plug transformer or from a desktop power supply. Input voltage should be
limited to b7V and +20V. Input voltage of +9VDC is typical. This input supplies the
on-board +5V regulator that powers the module.
Connector J1
Power may be supplied to the module through the pins J1-1 and J1-2. Use of this option
requires a regulated voltage input limited to the range of +3.3VDC to +5VDC. This input is
connected directly to the module power and ground planes. Care should be exercised not to
over-drive this input. Use of connector J1 to 3.3V to the module requires disabling the
voltage supervisor (LV1) by opening cut-trace CT-1. See the Low-Voltage Detect section
below. To re-enable the low-voltage supervisor, install a 1206 sized 0-ohm resistor at CT1.
Connector J1 may also be used to 5V power from the on-board regulator to external
modules attached to connector J1. The PWR_SEL option header determines how power is
routed to the module.
PWR_SEL Jumper
The PWR_SEL jumper is a 4-position option header that configures power routing on the
APS12C32SLK module. The module may be powered by an external transformer connected
to the PWR connector or through connector J1. The module may also source power to
auxiliary modules connected to the connector J1. Damage may occur if the J1 power input
pins are over-driven. Refer to the Figure 1 to determine correct PWR_SEL jumper setting.
Figure 1: PWR_SEL
1
2
Source power input from barrel connector PWR.
1
2
Source power input from connector J1.
1
2
Source power from barrel connector PWR and supply power to external
circuitry connected to J1.
