100
8168C-MCU Wireless-02/10
AT86RF212
Bit 6:4 – Reserved
Bit 3:0 – RX_ PDT_LEVEL
With these register bits, the receiver can be desensitized such that frames with an RSSI
value below a threshold level are not received. The threshold level can be calculated
according to the following formula if RX_PDT_LEVEL > 0.
RX_THRES [dBm] = RSSI_BASE_VAL + 3.1
RX_PDT_LEVEL
RSSI_BASE_VAL is described in section
6.4.3.
If register bits RX_PDT_LEVEL = 0 (reset value), this feature is disabled which
corresponds to the highest sensitivity.
If register bits RX_PDT_LEVEL > 0, the current consumption of the receiver in states
RX_ON and RX_AACK_ON is reduced by 500 A, refer to parameter
10.8.2 in section
7.3 Transmitter (TX)
7.3.1 Overview
The AT86RF212 transmitter utilizes a direct up-conversion topology. The digital
transmitter (TX BBP) generates the in-phase (I) and quadrature (Q) component of the
modulation signal. A digital-to-analog converter (DAC) forms the analog modulation
signal. A quadrature mixer pair converts the analog modulation signal to the RF
domain. The power amplifier (PA) provides signal power delivered to the differential
antenna pins (RFP, RFN). Both, the LNA the PA are internally connected to the
bidirectional differential antenna pins so that no external antenna switch is needed.
Using the default settings, the PA incorporates an equalizer to improve its linearity. The
enhanced linearity keeps the spectral side lobes of the transmit spectrum low in order to
meet the requirements of the European 868.3 MHz band.
If the PA boost mode is turned on, the equalizer is disabled. This allows to deliver a
higher transmit power of up to 10 dBm at the cost of higher spectral side lobes and
higher harmonic power.
In Basic Operating Mode, a transmission is started from PLL_ON state by either writing
TX_START to register bits TRX_CMD (register 0x02, TRX_STATE) or by a rising edge
of SLP_TR.
In Extended Operating Modes, a transmission might be started automatically depending
on the transaction phase of either RX_AACK or TX_ARET, refer to section
5.2.
7.3.2 Frame Transmit Procedure
The frame transmit procedure, including writing PSDU data into the Frame Buffer and
initiating a transmission, is described in section
8.2.7.3.3 Spectrum Masks
The AT86RF212 can be operated in different frequency bands, using different power
levels, modulation schemes, chip rates, and pulse shaping filters. The occupied
bandwidth of the transmit signal depends on the chosen mode of operation. Values
listed in
Table 7-9 are based on a default power setting (PHY_TX_PWR = 0x60) and
usage of the Continuous Transmission Test Mode with Frame Buffer content {0x01,
0x00}, refer to Appendix A on page
164.Knowledge of modulation bandwidth, power spectrum, and side lobes is essential for
proper system setup, i.e. non-overlapping channel spacing.