LMX5001VBC NSC [National Semiconductor], LMX5001VBC Datasheet - Page 5

• Manufacturer Part Number: LMX5001VBC
• Description: Dedicated Bluetooth Link Controller
• Manufacturer: NSC [National Semiconductor]

Functional Description
tooth radio. It also provides the following functions (under the
control of either a Link Management Controller, or a Host
processor performing Link Management Control functions):
LMX5001 COMMAND SET
In order to support the range of Bluetooth communication
modes, the LMX5001 has the ability to implement the follow-
ing commands from the Link Management Controller:
The LMX5001 can also be placed into an Idle State by the
Link Management Controller asserting SYSLOAD. SYS-
LOAD also start the system load process. During this pro-
cess, the transfer of information between LMX5001 Link
Controller and the Link Management Controller takes place.
The interface between the two is Link Controller Interface
(LCI). The formatting of the Command Set, along with Con-
figuration and Status data, sent via the LCI is further detailed
in the LCI sections of this Datasheet.
RECEIVE DATA AND CLOCK RECOVERY
Since Bluetooth is based on a packetized, wireless commu-
nications protocol, it is necessary to frame timing from the re-
ceived packets, before the data itself can be recovered. Also,
since Bluetooth supports both point-to-point and point-to-
multipoint connection, it is also necessary to establish
whether the received packet is addressed to the unit in ques-
tion.
In receive mode, the LMX5001 receives samples from the
LMX3162 at 8 times the Bluetooth Symbol rate (i.e., 8
Mbps). This ensures a +/- 1/8 bit accuracy for receive data
and frame/slot clocking. If the unit in question is operating as
a Slave, then the Slave (Frame/Slot) Counter is updated us-
ing the recovered frame/slot clock upon successful Access
Code correlation.
• Receive Data and Clock recovery
• Access Code correlation
• Frame/Slot Counters
• Radio control (LMX3162)
• Radio Signal Strength Indication (RSSI)
• DC Offset compensation
• Data transmission and receiving
• Link Management Controller communication (LCI)
• Power management
• Encryption
• Slave Receive with Continuous Correlation
• Slave Receive with Windowed Correlation
• Slave Transmit
• Master Receive
• Master Transmit
• Change to Master Clock
• Change to Slave Clock
• Power Down
• Slave Receive with Windowed Correlation, Encryption
• Slave Transmit, Encryption Enabled
• Master Receive, Encryption Enabled
• Master Transmit, Encryption Enabled
Enabled
(Continued)
5
The received samples are shifted into a 512 sample Buffer in
the correlator. The length of this buffer is fixed to enable the
correlation of a 64-bit Sync Word (8x oversampled) of the
Access Code.
DATA TRANSMISSION AND RECEIVING
Bluetooth data is transferred via a serial interface (LCI) with
the Link Management Controller. The transferred data is bro-
ken down to 8-bit packets. The LCI then uses a 10-bit pack-
age to send each of these 8-bit packets using a big-endian
mode.
The big-endian mode is illustrated in the Figure 2 below:
ACCESS CODE CORRELATION
Access Code Correlation is performed to establish whether a
packet’s payload is intended for the unit in question.
The Access Code to be correlated against the incoming Re-
ceive Data is passed to the LMX5001 from the Link Manage-
ment Controller via the LCI. It is then stored in a 64-bit AC
Buffer in the LMX5001.
The AC Buffer is then correlated with the incoming Receive
Data (stored in the RX Buffer) and the maximum correlation
achieved is transferred to the Correlation Max Buffer.
The Correlation Max is then compared with the contents of
the AC (Access Code) Threshold Buffer, to determine
whether the incoming Access Code sufficiently matches the
unit in question. If the Correlation Max exceeds the AC
Threshold, then the Control Registers “CORR” flag is
cleared, to indicate a correlation.
EXTERNAL CRYSTALS
There are two external crystals, one running at 16 MHz
(
rate crystal is used to drive the Bluetooth native clock in nor-
mal mode. This clock is also used as the Link Management
Controller clock input. The lower rate crystal is used when
the Bluetooth unit is in low power mode. In this mode, the
higher rate crystal is shut down so is the Link Management
Controller. Leaving only the lower rate crystal running to up-
date the internal Bluetooth native clock.
FRAME/SLOT COUNTERS
The LMX5001 maintains an internal counter. It is 28 bits in
length, to support the Bluetooth requirement for 2
The Bluetooth slot number is generated based on this
counter. It is also the basis for the Link Management firm-
ware to update its implementation of the Bluetooth Master
and Slave Counters. This clock is in half Bluetooth slot inter-
vals (312.5 µs).
LMX5001 LINK CONTROLLER INTERFACE (LCI)
All Host/Link Management Control of the LMX5001 (and
LMX3162) takes place via the serial LCI.
The signals associated with this port are:
• SYSLOAD
• SYSTICK
±
10 ppm) and the other at 128 kHz (
FIGURE 2. Big-endian Data Convention
±
125 ppm). The higher
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27
-1 slots.