Texas Instruments TRF4903, User Manual, Page: 5 / 26

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2.2 Operation
Demonstrating a Wireless Link
Circuit board features:
a On/Off switch
b Battery holder for two AAA batteries in series (batteries not included).
c-1, c-2 Headers used to access the MSP430F449 I/O ports.
d TRF4903 RF transmitter
e Antenna jumper (0-
Ω
resistor) used to select either the SMA connector or PCB
antenna (selecting both not recommended).
f On-board PCB antenna (default configuration). The antenna has modest gain and
radiates in the direction of the bend in the long arm.
g SMA connector footprint for an external antenna or test equipment (SMA connector
not included).
h Four-bit DIP switch used in the link demonstration mode to change the trans-
mit/receive frequencies. The switch is connected to MSP430 I/O ports P3.0, P3.1,
P3.2, and P3.3.
i Four buttons used for the demonstration game application, connected to MSP430
I/O ports P1.0 through P1.3.
j RS-232C connector
k JTAG connector
l TRF4903 I/O header used to monitor or control the TRF4903.
m Zero-
Ω
resistor R42, remove to disable the MSP430F449 (or short reset to ground
at JTAG connector).
n MSP430F449 microcontroller
A simple game is implemented in the firmware to demonstrate unidirectional RF communication between
the TRF4903 transmit board and the TRF6903 configured in the receive mode. The user starts the game
by pushing any sequence of four colored buttons. The corresponding colored LED’s light up on the receive
board in the same sequence.
•
Successful packet reception: The LED’s light up in same sequence as the transmit button sequence.
•
Communication error: NO LED’s illuminate on the receiving board if there was a communication error.
2.2.1 Preparing for Operation
Before operating the units as a demonstration, make sure that you have done the following:
•
Slide the on/off switch to ON
•
Place two AAA batteries on each demonstration board
•
Have the same 4-bit DIP switch (SW1) configuration on both boards
Table 1 shows the transmit and receive frequencies selected with the 4-bit DIP switch (SW1). Both circuit
boards must have the same channel switch settings in order for the demonstration game to operate
correctly.
Table 1. 4-Bit DIP Switch (SW1) Settings and Transmit Frequencies
1234 SW1 Setting TX Frequency (MHz) RX Frequency (MHz)
(1=On, 0=Off) 4903 TX Board 6903 RX Board
0000 902.3988 891.6992
TRF4903 With MSP430 Demonstration and Development Evaluation Kit SWRU010A – October 2004 – Revised May 2005 5