User's Manual

Interface Locations and Pinouts
1320x-QE128EVB Reference Manual, Rev. 0.0
4-2 Freescale Semiconductor
4.2 Power Management
The module can be powered from the DC power jack, the USB port, or the battery pack.
4.2.1 Supply Sources
Table 4-1 lists the supply sources, connectors, and voltages. Maximum board current draw is rated at 100
mA.
4.2.2 On/Off Switch (Hardware Reset)
The slide switch designated SW1 provides an on/off function and the only hardware reset to the main board
and subsystems.
• The hardware reset was implemented through power on/off because of the IO/reset configuration
of the MC9S08QE128 MCU. The MCU has a single pin that can be used as an external interrupt
request (IRQ) or hardware reset input. In this application the MC1320x transceiver requires use of
the external IRQ function, and as a result, the MCU cannot directly use the hardware reset pin. For
the module, the only hardware reset is to cycle main power through SW1.
• When the module is powered from the USB connection, the USB interface IC is always powered
and SW1 does not disconnect power from it. This has been done such that switching power via
SW1 does not disrupt connection with a PC and cause software driver problems with the
applications software.
4.2.3 Power On Indicator
Green light emitting diode LED5 is the power on indicator for any source. The LED is active anytime a
power source is present and SW1 is ON. If the power source is the USB connection, LED5 will be inactive
when SW1 is open (off), but the USB interface device will be powered as long as connected to the USB
bus.
Table 4-1. Power Supply Sources
Source Connector
Min
(Volts)
Typical
(Volts)
Max
(Volts)
Notes
DC Source J2 4.4 5 12 Use DC only source. The connector is a 2 mm DC power jack;
positive center conductor.
USB J12 4.4 5 5.25 Per USB specification. Power from USB connector.
AA Battery Pack BT1 ~2.0 3 3.2 Two AA cells. Battery pack is automatically disabled by either
DC source or USB.