ATMEGA64RFR2_14 Datasheet, PDF (90/611 Pages) ATMEL Corporation – Microcontroller with Low Power

Additionally, the PLL supports all frequencies from 2322 MHz to 2527 MHz with 500
kHz frequency spacing. The frequency is selected by CC_BAND (see "CC_CTRL_1 –
Channel Control Register 1" on page 136) and CC_NUMBER (see "CC_CTRL_0 –
Channel Control Register 0" on page 136).
Table 9-26 shows the settings of the register bits CC_BAND and CC_NUMBER.
Table 9-26. Frequency Bands and Numbers
CC_BAND⁽¹⁾ CC_NUMBER Description
0x0
Not used
Channels according to IEEE 802.15.4; frequency selected
by register bits CHANNEL (register 0x08, PHY_CC_CCA).
0x1, … , 0x7 0x00 – 0xFF reserved
0x8
0x00 – 0x1F reserved
0x8
0x20 – 0xFF 2322 MHz – 2433.5 MHz
Fc [MHz] = 2306 + 0.5 • CC_NUMBER
0x9
0x00 – 0xBA 2434 MHz – 2527 MHz.
Fc [MHz] = 2434 + 0.5 • CC_NUMBER
0x9
0xBB – 0xFF reserved
0xA, … , 0xF 0x00 – 0xFF reserved
Notes: 1. CC_CTRL_0 and CCTRL_1 form a combined16 bit register. Changed CC_BAND
values in register CC_CTRL_1 are effective after writing to register CC_CTRL_0.
9.6.7 Automatic Filter Tuning (FTN)
The FTN is incorporated to compensate device tolerances for temperature, supply
voltage variations as well as part-to-part variations of the radio transceiver. The filter-
tuning result is used to correct the transfer function of the analog baseband filter and
the time constant of the PLL loop-filter (refer to "General Circuit Description" on page
33).
An FTN calibration cycle is initiated automatically when entering the radio transceiver
TRX_OFF state from the SLEEP or RESET state.
Although receiver and transmitter are very robust against these variations, it is
recommended to initiate the FTN manually if the radio transceiver does not use the
SLEEP state. A calibration cycle is to be initiated in states TRX_OFF, PLL_ON or
RX_ON if necessary. This applies in particular to the High Data Rate Modes with a
much higher sensitivity to variations of the BPF transfer function. The recommended
calibration interval is 5 min or less.
9.7 Radio Transceiver Usage
This section describes the basic procedures to receive and transmit frames with the
radio transceiver.
9.7.1 Frame Receive Procedure
A frame reception comprises of two actions: The PHY listens for a frame, receives and
demodulates the frame to the Frame Buffer and signalizes its reception to the
application software. The application software reads the available frame data from the
Frame Buffer after or during the progress of the frame reception.
While in state RX_ON or RX_AACK_ON the radio transceiver searches for incoming
frames on the selected channel. First a TRX24_RX_START interrupt indicates the
detection of an IEEE 802.15.4 compliant frame assuming the appropriate interrupts are
90 _{ATmega256/128/64RFR2}
8393C-MCU Wireless-09/14