LMX9820 datasheet(21/40 Pages) NSC

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10.0 Integrated Firmware

The LMX9820 includes the full Bluetooth stack up to

RFComm to support the following profiles:

• GAP (Generic Access Profile)

• SDAP (Service Discovery Application Profile)

• SPP (Serial Port Profile)

Figure 15 shows the Bluetooth protocol stack with com-

mand interpreter interface. The command interpreter offers

a number of different commands to support the functional-

ity given by the different profiles. Execution and interface

timing is handled by the control application.

The chip has an internal data area in Flash that includes

the parameters shown in Table 25 on page 22.

10.1 FEATURES

10.1.1 Operation Modes

On boot-up, the application configures the module follow-

ing the parameters in the data area.

Automatic Mode

No Default Connections Stored:

In Automatic mode the module is connectable and discov-

erable and automatically answers to service requests. The

command interpreter listens to commands and links can be

set up. The full command list is supported.

If connected by another device, the module sends an event

back to the host, where the RFComm port has been con-

nected, and switches to transparent mode.

Default Connections Stored:

If default connections were stored on a previous session,

once the LMX9820 is reset, it will attempt to connect each

device stored within the data Flash three times. The host

will be notified about the success of the link setup via a link

status event.

Command Mode

In Command mode, the LMX9820 does not check the

default connections section within the Data Flash. If con-

nected by another device, it will NOT switch to transparent

mode and continue to interpret data sent on the UART.

Transparent Mode

The LMX9820 supports transparent data communication

from the UART interface to a bluetooth link.

If activated, the module does not interpret the commands

on the UART which normally are used to configure and

control the module. The packages don’t need to be format-

ted as described in Table 27 on page 24. Instead all data

are directly passed through the firmware to the active blue-

tooth link and the remote device.

Transparent mode can only be supported on a point-to-

point connection. To leave Transparent mode, the host

must send a UART_BREAK signal to the module

Force Master Mode

In Force Master mode tries to act like an Accesspoint for

multiple connections. For this it will only accept the link if a

Master/slave role switch is accepted by the connecting

device. After successful link establishment the LMX9820

will be Master and available for additional incoming links.

On the first incoming link the LMX9820 will switch to trans-

parent depending on the setting for automatic or command

mode. Additional links will only be possible if the device is

not in transparent mode.

10.1.2 Default Connections

The LMX9820 supports the storage of up to 3 devices

within its NVS. Those connections can either be connected

after reset or on demand using a specific command.

10.1.3 Event Filter

The LMX9820 uses events or indicators to notify the host

about successful commands or changes at the bluetooth

interface. Depending on the application the LMX9820 can

be configured. The following levels are defined:

• No Events:

– The LMX9820 is not reporting any events. Optimized

for passive cable replacement solutions.

• Standard LMX9820 events:

– only necessary events will be reported

• All events:

– Additional to the standard all changes at the physical

layer will be reported.

10.1.4 Default Link Policy

Each Bluetooth Link can be configured to support M/S role

switch, Hold Mode, Sniff Mode and Park Mode. The default

link policy defines the standard setting for incoming and

outgoing connections.

Figure 15. LMX9820 Software Implementation

Command Interpreter

Control Application

SPP

GAP

SDAP

RFComm

L2CAP

Link Manager

Baseband

SDP

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