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11
Users Guide
XE1401SK Hardware
Identifier Location
Description
Identifier Location
Description
JP8 6
CODEC
Enable/Disable SW2 23 RESET
push-button
JP11
3
UART Interface
SW3
4
Radio type switch
JP12
14
Protection diode CR6 bypass
TP5
7
CODEC Sandman functions
JP13 18
XE1401SK power supply
selector
U1
8
XE1401 baseband controller
SW1 17
ON/OFF
switch
U2 2
XE3006
CODEC
Note!
To locate all jumpers and components referred in these following sections, please see
5.2 XE1401SK
Motherboard Overview
and
6. SCHEMATICS
.
5.2.1 Power
Supply
The power source for the XE1401SK motherboard can be selected by JP13. The XE1401SK can be power
supplied by using the onboard AAA batteries, via the USB port or by an external supply directly connected to the
connector J1.
If an external power supply is used, it should be set between 4V and 10 V DC (see polarity signs drawn on the
motherboard PCB) and must be able to provide at least 200mA to fit with the switching transient current that may
be encountered during start-up.
All USB components are only powered if the USB port is used. If a USB cable is connected, the RS232 port is
automatically disabled. Therefore it is not possible to power supply the XE1401SK via the USB port and
simultaneously use the RS232 port for the UART communication. For further details see chapter
6. SCHEMATICS
.
5.2.2 Voltage
Regulators
Two diodes (CR2 and CR4) protect the board from reverse polarity if an external power supply is applied.
The LP2986 voltage regulators (U4 and U5) supply the board with 3.0V and 3.3V. These regulators can provide a
maximum output current of 200mA each.
The regulator U4 supplies the entire board with 3.0V except the USB components while U5 supplies all USB
components with 3.3V. U5 is only active when the USB cable is connected, otherwise it is shut down.
5.2.3
Power Supply for External Application Board
The power supply source for an external application board (connected to JP2), can be selected by JP7 (see
5.3
Motherboard Jumper Settings
).
Note!
The XE1401SK motherboard does not allow being reversed powered by the external application board.
Therefore a protection diode (CR6) is present. This diode can be shorted via JP12 if the voltage dropout is not
acceptable for the external application board powered by the XE1401SK (see chapter
5.3 Motherboard Jumper
Settings
and
6. Schematics
).
