User Manual

MPR/MIB User’s Manual
Wireless Sensor Networks
Doc. # 7430-0021-06 Rev. A Page 25
7 RADIOS
7.1 MICA2 and MICA2DOT
7.1.1 Radio Considerations
The radio on the MICA2 and MICA2DOT is capable of multiple channel operation, within the
intended band of operation. The MPR420/MPR520 can span up to 4 channels of operation in the
315 MHz band, the MPR410/MPR510 can span up to 4 channels of operation in the 433 MHz
band (433.05–434.79 MHz). The MPR400/MPR500 can operate in two frequency regions: 868–
870 MHz (up to 4 channels) and 902–928 MHz (up to 54 channels). The actual number of
possible channels is higher for all the MICA2/MICA2DOT motes. However, it is recommended
that the adjacent channel spacing should be at least 500 kHz to avoid adjacent channel
interference thereby reducing the number of available channels. A tutorial on how to change
frequency is available at http://www.tinyos.net/tinyos-1.x/doc/mica2radio/CC1000.html.
7.1.2 Radio Transmission Power
The radio on the MICA2/MICA2DOT can be adjusted for a range of output power levels. The
register in the radio that controls the RF power level is designated PA_POW at address 0x0B,
and the values and their corresponding RF outputs are provided on Table 7-1 below. It shows the
closest programmable value for output powers in steps of 1 dBm. For power down mode the
Chipcon datasheet says, “the PA_POW should be set to 00h [0x00] for minimum leakage
current.”