Texas Instruments CC2520, User Manual

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7.2 Mode selection switch
SmartRF05EB has a mode selection switch (P21) that allows two minor configurations of the
evaluation board.
Figure 16 - EB Mode Selection switch
In the NORMAL position, the evaluation board is in a normal operating mode, enabling
support in hardware both for debugging of an external SoC and a special packet sniffer
interface for the CC2520EM.
The CC2511JOYSTICK position is primarily intended for the special case where a custom
application is running on the CC2511 using the joystick (JOY_LEVEL and JOY_MOVE) for
user input. In this position, neither the external debug interface nor the hardware support for
CC2520 packet sniffer will work. P0.0 is connected to the JOY_MOVE signal and P0.6 is
connected to the JOY_LEVEL signal.
The switch is by default placed in the NORMAL position.
7.3 Power Sources
There are four possible solutions for applying power to the SmartRF05EB. The power source
can be selected using the power source selection jumper on header P11.
Figure 17 - Main power switch and power selection jumper
The main power supply switch (P8) turns off all power sources, unless an external power
supply is connected to the board, overriding the onboard voltage regulators.
7.3.1 Battery power
The evaluation board includes a battery holder for two 1.5V AA batteries on the reverse side
of the PCB: Normal AA batteries can be used and the on board regulator supplies 3.25 V to
the board. The power source selection jumper should short circuit pin 1 and 2 of header P11.
A LOW BATT LED on the board will be lit when the voltage on the board drops beneath 1.56
V. Note that this function is only active when powering the board using batteries.
7.3.2 DC Jack
SmartRF05EB has a connector with standard DC jack power connectors with a 2.5mm centre
pin. The centre pin is used for the positive voltage. A 4-10 V DC power supply should be
used. The onboard voltage regulator supplies approx 3.05 V to the board. The power source
selection jumper should short circuit pin 2 and 3 of header P11.