Application Report
SWRA049 – September 2005
Operating the TRF6903 With MSP430 Evaluation Kit in the
315-MHz or 433-MHz ISM Band
Raju Karingattil and Iboun Sylla
........................................................................ Digital Radio Applications
ABSTRACT
This application note discusses the implementation details to operate the TRF6903 with
MSP430 evaluation kit in the 315-MHz and 433-MHz ISM band. A separate version of
firmware has been developed for this purpose and is available for download from the
website at www.ti.com/ismrf.
1
2
3
4
Contents
Introduction ..........................................................................................
Transceiver Modifications .........................................................................
Operation at 315-MHz and 433-MHz ISM Band ................................................
References ..........................................................................................
1
2
6
7
List of Figures
1
2
3
EasyRF Software at 433 MHz .................................................................... 3
EasyRF Software at 315 MHz .................................................................... 4
Schematic of TRF6903 Demo Board ............................................................ 5
List of Tables
1
1
2
Cross Reference of Components Between EasyRF and Demo Board ...................... 2
Component Value of Receiver Input Matching for 315 MHz and 433 MHz ................. 5
3
Component Values for Transmitter Output Matching for 315 MHz and 433 MHz
.........
6
Introduction
This application note details the modifications needed to make the TRF6903 demo board with MSP430
functional at 315 MHz or 433 MHz. The default frequency of operation of the demo board is 915 MHz. The
following steps are needed for converting the demo board to be functional at 315 or 433 MHz.
1.1
Hardware Modifications
A few components in the receiver input and transmitter output need to be changed. The details are
provided in Table 2 and Table 3.
The printed PCB antenna was designed for 915 MHz and will not function efficiently at 315 MHz or 433
MHz. The 0-Ω resistor at JP1 needs to be switched to connect the RF input and output to the SMA
connector. Use an external antenna tuned for either 315 MHz or 433 MHz.
SWRA049 – September 2005
Operating the TRF6903 With MSP430 Evaluation Kit in the 315-MHz or 433-MHz ISM Band
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www.ti.com
Transceiver Modifications
1.2
Software Modifications
A separate set of firmware has been developed to evaluate the TRF6903 with MSP430 evaluation kit in
the 315-MHz or 433-MHz ISM Band. See the TRF6903 With MSP430 Demonstration and Development
Evaluation Kit user’s guide (SWRU008) for detailed information on the evaluation kit.
2
Transceiver Modifications
The EasyRF software available for TRF6903 at the website (www.ti.com/ismrf) makes it easy for
determining the new component values.
Note:
The component designations used in the EasyRF software is different from the
designations on the demo board.
The cross reference of the components between the software program and demo board is listed in
Table 1.
Table 1. Cross Reference of Components Between EasyRF and Demo Board
EasyRF SCHEMATIC
COMPONENT DESIGNATION
2.1
DEMO BOARD SCHEMATIC
COMPONENT DESIGNATION
C6
C9
C8
C10
C9
C11
L3
L4
L4
L6
C11
C14
C12
C64
C13
C48
C14
C15
L5
L5
EasyRF Software
After loading the EasyRF software use following steps to compute the right component value for the input
and output matching:
• Choose operating band (315 / 433 / 868 / 915 MHz)
• Enter value of center frequency
• Define type of modulation scheme (FSK/OOK)
• Define coding scheme
• Define peak-to-peak frequency deviation (FSK only)
• Define bit rate
• Define training sequence
• Define number RX training bit
• Define PLL Ref Freq
• Choose the of charge current pump
• Choose loading capacitor XTUNE
• Press calculate button to compute value of the components
Figure 1 and Figure 2 show a snapshot of the EasyRF software.
2
Operating the TRF6903 With MSP430 Evaluation Kit in the 315-MHz or 433-MHz ISM Band
SWRA049 – September 2005
www.ti.com
Transceiver Modifications
Figure 1. EasyRF Software at 433 MHz
SWRA049 – September 2005
Operating the TRF6903 With MSP430 Evaluation Kit in the 315-MHz or 433-MHz ISM Band
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Transceiver Modifications
Figure 2. EasyRF Software at 315 MHz
4
Operating the TRF6903 With MSP430 Evaluation Kit in the 315-MHz or 433-MHz ISM Band
SWRA049 – September 2005
www.ti.com
Transceiver Modifications
Figure 3. Schematic of TRF6903 Demo Board
2.2
Receiver Input Modifications
The matching components at the receiver input have the task of converting the differential input of low
noise amplifier (LNA) to the 50-Ω connector (or antenna, switch etc.). Proper matching at the input is
necessary to avoid degradation of noise figure and gain of the LNA. The four components that need
modifications are C9, C10, C11, and L4.
The list of new component values needed for receiver input match are listed in Table 2.
Table 2. Component Value of Receiver Input Matching for 315 MHz and 433 MHz
DEMO BOARD
COMPONENT DESIGNATIONS
RX_LNA Input Matching Network
SWRA049 – September 2005
COMPONENT VALUES
315 MHz
433 MHz
C9
330 pF
180 pF
C10
15 pF
8.2 pF
C11
15 pF
8.2 pF
L4
27 nH
22 nH
Operating the TRF6903 With MSP430 Evaluation Kit in the 315-MHz or 433-MHz ISM Band
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Operation at 315-MHz and 433-MHz ISM Band
2.3
Transmitter Output Modifications
The transmitter output needs to be modified with the appropriate components to maximize the output
power. The list of new component values needed for transmitter output match is listed in Table 3.
Table 3. Component Values for Transmitter Output Matching for 315 MHz and 433 MHz
DEMO BOARD
COMPONENT DESIGNATIONS
Power Amplifier Output
Matching Network
3
COMPONENT VALUES
315 MHz
433 MHz
C14
390 pF
270 pF
C64
7.5 pF
6.8 pF
C15
390 pF
270 pF
L6
75 nH
39 nH
L5
560 nH
470 nH
C48
390 pF
270 nF
Operation at 315-MHz and 433-MHz ISM Band
Note:
The DIP switch is disabled in the 315-MHz and 433-MHz operation and the frequency is
automatically selected and displayed by the EasyRF software.
3.1
Downloading the Code
The MSP-TRF6903-DEMO comes with source code installed on the MSP430 to run the demo program.
The user can develop new application software that can be downloaded to the MSP430 MCU through the
JTAG connector. Since the demo code size is around 8 kB, only unrestricted versions of the IAR
development environment (not the Kickstart version) must be used for downloading and modifying the
code. The workspace file for compiling the demo source code is TRF6903Demo_US.eww, developed with
IAR compiler version 3.20a. The following steps show how to open the project file and program the
MSP430.
1. Insert the two AAA batteries and slide the on/off switch to ON.
2. Start the Workbench (START→ PROGRAMS → IAR SYSTEMS → IAR EMBEDDED WORKBENCH)
3. Use FILE→OPEN WORKSPACE to open the workspace file at: <Installation root>\...\
6903Demokit_433MHz_WS.eww
4. Use PROJECT→BUILD ALL to compile and link the source code. You can view the source code. You
can view the source by double-clicking Common Sources and then double-clicking on the source files
in the workspace window.
5. Ensure that the C-SPY debugger is properly configured for the parallel port used. Choose
PROJECT→OPTIONS→ FET DEBUGGER and select→ LPT1 (default) or LPT2 or LPT3 for the
parallel port configuration.
6. Use PROJECT→ DEBUG to start C-SPY. C-SPY erases the device flash and downloads the
application object file.
7. In C-SPY, use DEBUG→GO to start the application.
8. In C-SPY, use DEBUG→STOP DEBUGGING to exit C-SPY.
9. In Workbench, use FILE→EXIT to exit Workbench.
The MSP430 is now programmed with the game demonstration code and ready to operate in 315 MHz or
433 MHz.
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Operating the TRF6903 With MSP430 Evaluation Kit in the 315-MHz or 433-MHz ISM Band
SWRA049 – September 2005
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References
4
References
1.
2.
3.
4.
TRF6903 Single-Chip Multiband RF Transceiver Data sheet (SWRS022)
TRF6903 Design Guide (SWRU009)
TRF6903 with MSP430 Demonstration and Development Evaluation Kit User’s Guide (SWRU008)
Implementing a Bidirectional Wireless UART Application With TRF6903 and MSP430 (SLAAxx)
SWRA049 – September 2005
Operating the TRF6903 With MSP430 Evaluation Kit in the 315-MHz or 433-MHz ISM Band
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