Preliminary
11-128
RF2968
Rev A13 010912
11
Application Information
Baseband Interface
The RF2968 RF transceiver serves as the physical layer (PHY) in a Bluetooth system and supports the BlueRF interface
between PHY and baseband devices. The RF2968 contains the data demodulation, DC compensation, and data and
clock extraction circuitry while the access code correlator function takes place in the baseband.
There are two interfaces between the RF2968 and the baseband. The serial interface provides the path for control data
exchange, and the bidirectional interface provides the path for modem, timing, and chip power control signals. Figure 1
shows bidirectional signals with arrowheads on both ends of the line.
Serial Interface
Control data is exchanged between the RF2968 and the baseband by means of the DBus serial interface protocol.
BDCLK, BDDATA,and BnDEN are the signals comprising the serial interface. The baseband is the master device, initi-
ating all accesses to the RF2968 registers. The data registers of the RF2968 are programmed or recalled according to
the specified command format and address assignments. Data packets are transmitted MSB first.
Serial Data Packet Format
During a write, the baseband drives out each bit of the packet on the falling edge of BDCLK. The RF2968’s data register
is updated with the shift register contents on the first falling edge of BDCLK after BnDEN is driven high. See Figure 2.
Field
Number of Bits
Comments
Device Address
3 [A7:A5]
“101” for PHY
Read/Write
1 [R/W]
“1” =Read, “0” =Write
Register Address
5 [A4:A0]
Maximum of 32 registers
Data
16 [D15:D0]
The RF2968 is programmed in Write mode and returns its register contents
in Read mode.
BDATA1
BPKTCTL
BXTLEN
BnPWR
BRCLK
BDDATA
BDCLK
BnDEN
Figure1. Baseband/RF2968 Interface
BDCLK
...
BnDEN
...
D15
D14
A6
A5
A3
A2
A1
A0
A7
A4
D1
D2
D0
A6
A7
don't
care
BDDATA
R/W= write = 0
Figure 2. DBus Write Programming Diagram
British ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
