AT86RF230_09 ATMEL [ATMEL Corporation], AT86RF230_09 Datasheet - Page 52

• Manufacturer Part Number: AT86RF230_09
• Description: Low Power 2.4 GHz Transceiver for ZigBee, IEEE 802.15.4, 6LoWPAN, RF4CE and ISM
• Manufacturer: ATMEL [ATMEL Corporation]

8.4.1 Overview
8.4.2 Reading RSSI
8.4.3 Data Interpretation
8.4.4 Register Description
52
AT86RF230
Bit
0x06
Read/Write
Reset value
Bit
0x06
Read/Write
Reset value
The RSSI is a 5-bit value indicating the receive power in the selected channel, in steps
of 3 dB. No attempt is made to distinguish between IEEE 802.15.4 signal and other
signal source, only the received signal power is evaluated. The RSSI provides the basis
for ED measurement.
Using the Basic Operating Mode, the RSSI value is valid at any RX state, and is
updated every 2 μs. The current RSSI value is stored to the PHY_RSSI register.
Note, it is not recommended to read the RSSI value when using the Extended
Operating Mode. The automatically generated ED value should be used alternatively
(see section 8.3).
The PHY_RSSI is an 8-bit register, however, the value is represented in the lowest five
bits [4:0] and the range is 0 – 28.
An RSSI value of 0 indicates an RF input power of < -91 dBm. For an RSSI value in the
range of 1 to 28, the RF input power can be calculated as follows:
Register 0x06 (PHY_RSSI)
The PHY_RSSI register is a multi purpose register to indicate the current received
signal strength (RSSI) and the FCS validity of a received frame.
• Bit 7 – RX_CRC_VALID
Refer to section 8.2.5.
• Bit [6:5] – Reserved
• Bit [4:0] – RSSI
The register bits RSSI contain the result of the automated RSSI measurement. The
value is updated every 2 μs in receive states.
The read value is a number between 0 and 28 indicating the received signal strength as
a linear curve on a logarithmic input power scale (dBm) with a resolution of 3 dB. An
RSSI value of 0 indicates an RF input power of < -91 dBm (see parameter 11.7.17), a
value of 28 a power of ≥ -10 dBm (see parameter 11.7.18).
P
RF
RX_CRC_VALID
= RSSI_BASE_VAL + 3•(RSSI - 1)
R
R
7
0
3
0
R
R
6
0
2
0
Reserved
RSSI
R
R
5
0
1
0
RSSI
R
R
4
0
0
0
5131E-MCU Wireless-02/09
PHY_RSSI
PHY_RSSI