National CP3BT26 manual Bluetooth Controller, RF Interface, X1CKI/BBCLK, Rfdata, Rfsync

CP3BT26

15.0 Bluetooth Controller

The integrated hardware Bluetooth Lower Link Controller (LLC) complies to the Bluetooth Specification Version 1.1 and integrates the following functions:

Figure 12 shows the interface between the CP3BT26 and the LMX5252 radio chip.

+2.8V

„4.5K-byte dedicated Bluetooth data RAM

„1K-byte dedicated Bluetooth Sequencer RAM

„Support of all Bluetooth 1.1 packet types

„Support for fast frequency hopping of 1600 hops/s

„Access code correlation and slot timing recovery circuit

„Power Management Control Logic

„BlueRF-compatible interface to connect with National’s LMX5252 and other RF transceiver chips

IOVCC

RFDATA

PG1/RFCE

CP3BT26

PG2/BTSEQ1

VCC

BBDATA_1

BXTLEN

LMX5252

BPKTCTL

For a detailed description of the interface to the LMX5252, consult the LMX5252 data sheet which is available from the National Semiconductor wireless group. National provides software libraries for using the Bluetooth LLC. Documenta- tion for the software libraries is also available from National Semiconductor.

15.1RF INTERFACE

The CP3BT26 interfaces to the LMX5251 or LMX5252 radio chips though the RF interface.

Figure 11 shows the interface between the CP3BT26 and the LMX5251 radio chip.

VCC

PG3/SCLK BDCLK

PG4/SDAT BDDATA

PG5/SLE BDEN#

X1CKI/BBCLK BRCLK

DS320

Figure 12. LMX5252 Interface

IOVCC

RFDATA

PG0/RFSYNC

CP3BT26

PG1/RFCE

PG3/SCLK

PG4/SDAT

PG5/SLE

X1CKI/BBCLK

VDD_DIG_IN

TX_RX_DATA

TX_RX_SYNC

LMX5251

CE

CCB_CLOCK

CCB_DATA

CCB_LATCH

BBP_CLOCK

The CP3BT26 implements a BlueRF-compatible interface, which may be used with other RF transceiver chips.

15.1.1RF Interface Signals

The RF interface signals are grouped as follows:

„Modem Signals (BBCLK, RFDATA, and RFSYNC)

„Control Signal (RFCE)

„Serial Interface Signals (SCLK, SDAT, and SLE)

„Bluetooth Sequencer Status Signals (BTSEQ1, BTSEQ2, and BTSEQ2)

X1CKI/BBCLK

The X1CKI/BBCLK pin is the input signal for the 12-MHz clock signal. The radio chip uses this signal internally as the 12× oversampling clock and provides it externally to the

DS316

Figure 11. LMX5251 Interface

CP3BT26 for use as the Main Clock.

RFDATA

The RFDATA signal is the multiplexed Bluetooth data re- ceive and transmit signal. The data is provided at a bit rate of 1 Mbit/s with 12× oversampling, synchronized to the 12 MHz BBCLK. The RFDATA signal is a dedicated RF inter- face pin. This signal is driven to a logic high level after reset.

RFSYNC

In receive mode (data direction from the radio chip to the CP3BT26), the RFSYNC signal acts as the frequency cor- rection/DC compensation circuit control output to the radio chip. The RFSYNC signal is driven low throughout the cor- relation phase and driven high when synchronization to the received access code is achieved.

In transmit mode (data direction from the CP3BT26 to the radio chip), the RFSYNC signal enables the RF output of the radio chip. When the RFSYNC pin is driven high, the RF

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