DVK-BTM521 Laird Technologies, DVK-BTM521 Datasheet - Page 95

• Manufacturer Part Number: DVK-BTM521
• Description: BT MM DEV KIT
• Manufacturer: Laird Technologies
• Type: Transceiver, Bluetoothr

Specifications of DVK-BTM521

• Frequency: 2.4GHz
• Interface Type: RS-232
• Processor Series: BTM521
• Silicon Manufacturer: Laird Technologies
• Kit Application Type: Communication & Networking
• Application Sub Type: Bluetooth
• Kit Contents: Development Board & Software Tools
• Features: Supports CSR
• Rohs Compliant: Yes
• For Use With/related Products: BTM521
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: DVK-BTM521

BTM520/521
Bluetooth
AT COMMAND SET
REFERENCE
95 www.lairdtech.com
®
Multimedia Plus Module
10. Maximum RF-Tx Power Level
11. Manufacturing Info String
12. Bluetooth version
13. Legacy Issues (BT2.0)
14. Factory Default UART Baud Rate
The maximum RF transmit power level for all operation states (inquiring/connecting/in connection)
is controlled by S541 / S542.
A string with manufacturing information can be retrieved by “ATI200”.
The Bluetooth version can be queried by “ATI18”.
There are some special cases if a legacy device (BT2.0 or earlier, e.g., BISM2) requests a connection to
a BTM device (BT2.1).
General bonding does not work if initiated by the legacy device. Instead, the legacy device must
initiate dedicated bonding first (=pairing, BISM2: “AT+BTW<BdAddr>”). After successful pairing,
the connection can be initiated by the legacy device (BISM2: “ATD<BdAddr>”).
BTM devices are capable of operating at a very wide range of baud rates. S Registers 520 and 521
allow the baud rate to be set.
As long as the equation BAUDRATE * 0.004096 produces an integer value, then there will be 0%
error in clocking for that baud rate.
So it is possible to set a baud rate that a PC cannot cope with, and in that circumstance it is virtually
impossible to communicate with it.
To cater for this circumstance, the BTM device will come out of reset using 9600,N,8,1 comms settings
for exactly 750 milliseconds and then revert to the communication parameters as per the S Registers.
If the host sends the string !<BISM>!<cr> where <cr> is the carriage return character within that
750ms period, then the module will remain at 9600,N,8,1 and will also configure itself using factory
default S Register values.
If connected to a PC using Ezurio Terminal, the module can be reset to the factory default baud rate
as follows:
Right click in the Ezurio Terminal window  Factory Default  Via BREAK/CMD @ 9600
(Tested with version 6.7.2 of Ezurio Terminal)
Figure 3.29: Sniff Mode Example
Laird Technologies