When a DR-TRC103 radio board is initially power on, it is configured as follows:
Operating Frequency:
DR-TRC103-868-EV 868.35 MHz
DR-TRC103-915-EV 916.50 MHz
DR-TRC103-950-EV 950.00 MHz
Power: +10 dBm
Frequency Deviation: ±50 kHz
Data Rate: 25 kb/s
Receiver Baseband Bandwidth: 100 kHz
The radio board is also initially configured in Receive Continuous Mode (see the TRC103 datasheet for an explanation of
continuous mode, buffered data mode, packet data mode, etc.). In receive continuous mode, the MODE LED will be
green. Receive continuous mode allows the user to connect a modulated signal from a signal generator source onto the
board through a short, coaxial cable and verify the demodulated signal with an oscilloscope through the DAT pin.
Briefly pressing the MODE button once configures the board into Transmit Continuous Mode. The Mode LED will change
color from green to yellow. This mode turns on the transmitter. The frequency and output power may be verified on a
spectrum analyzer. A square-wave modulating signal may be applied to the DAT pin and modulation observed on the
spectrum analyzer.
Briefly pressing the MODE button again configures the board into Sleep Mode. The Mode LED will turn off. By connecting
an ammeter across the terminals of J1, with the jumper removed, the user can verify the very low sleep current of the
TRC103 device.
As shown in Figure 11, potentiometer R7 can be used to adjust the transmit power level. To increase the output power,
rotate the potentiometer screw clockwise. To decrease the power, rotate the potentiometer screw counterclockwise.
The transmit power is divided into 8 levels. Adjusting R7 adjusts the voltage level to the A-to-D converter (ADC) in the
host microcontroller. The microcontroller periodically samples R7 for a change, and updates the transmit power register
when it detects a change in voltage level. Each time the microprocessor updates the transmit power register the SPI LED
D2 will flash indicating an SPI write.
©2015 by Murata Electronics N.A., Inc.
DR-TRC103-DK User’s Guide (2015/04/17) Page 10 of 22 www.murata.com