AT86RF212 Atmel Corporation, AT86RF212 Datasheet - Page 140

• Manufacturer Part Number: AT86RF212
• Manufacturer: Atmel Corporation

Specifications of AT86RF212

• Max. Operating Frequency: 0 MHz
• Crypto Engine: AES
• Operating Voltage (vcc): 1.8 to 3.6
• Frequency Band: 700/800/900MHz
• Max Data Rate (mb/s): 1
• Antenna Diversity: No
• External Pa Control: Yes
• Power Output (dbm): 10
• Receiver Sensitivity (dbm): -110
• Receive Current Consumption (ma): 9.0
• Transmit Current Consumption (ma): 18 at 5dBm
• Link Budget (dbm): 120

9.3 Differential Output supporting Software controlled Antenna Diversity
9.3.1 Overview
9.3.2 Application Example
140
AT86RF212
Table 9-10. Register 0x06 (PHY_RSSI)
• Bit 7 – RX_CRC_VALID
Refer to section 6.3.5.
• Bit 6:5 – RND_VALUE
The 2-bit random value can be retrieved by reading register bits RND_VALUE. Note
that the radio transceiver shall be in one of the Basic Operating Mode receive states.
• Bit 4:0 – RSSI
Refer to section 6.4.4.
Digital output pins DIG1 and DIG2 can be used to drive a general purpose differential
signal. The following sections describe software controlled antenna diversity as one
possible application.
Due to multipath propagation effects between network nodes, the receive signal
strength may vary and affects the link quality, even for small changes of the antenna
location. These fading effects can result in an increased error floor or loss of the
connection between devices.
To improve the reliability of a RF connection between network nodes, antenna diversity
can be applied to reduce effects of multipath propagation and fading. Antenna diversity
uses two antennas to select the most reliable RF signal path. To ensure highly
independent receive signals on both antennas, the antennas should be carefully
separated from each other.
The AT86RF212 supports software controlled antenna diversity, i.e. the microcontroller
controls which antenna is used for transmission and reception. This is done by register
settings.
Antenna Diversity can be used in Basic and Extended Operating Modes and can also
be combined with other features and operating modes like High Data Rate Modes and
RX/TX Indication.
A block diagram for a typical application is shown in Figure 9-6.
The use of pins 9 and 10 (DIG 1 and DIG2) for Antenna Diversity is enabled by
ANT_EXT_SW_EN = 1 (register 0x0D, ANT_DIV). In this case, the internal connection
of the control pins 9 and 10 to digital ground is disabled (refer to section 2.2.2), and
they provide a differential control signal to the antenna switch (SW1).
Bit
Name
Read/Write
Reset Value
Bit
Name
Read/Write
Reset Value
7
RX_CRC_VALID
R
0
3
RSSI[3]
R
0
6
RND_VALUE[1]
R
0
2
RSSI[2]
R
0
5
RND_VALUE[0]
R
0
1
RSSI[1]
R
0
8168C-MCU Wireless-02/10
4
RSSI[4]
R
0
0
RSSI[0]
R
0