DVK-BTM411 Laird Technologies, DVK-BTM411 Datasheet - Page 42

• Manufacturer Part Number: DVK-BTM411
• Description: BLUETOOTH EVAL BOARD BTM411
• Manufacturer: Laird Technologies
• Type: Transceiverr

Specifications of DVK-BTM411

• Frequency: 2.4GHz
• Wireless Frequency: 2.402 GHz to 2.48 GHz
• Interface Type: UART
• Data Rate: 2.1 Mbps
• Operating Voltage: 3 V to 3.3 V
• Antenna: Multilayer Ceramic Integrated
• Operating Temperature Range: - 30 C to + 70 C
• Output Power: 4 dBm
• Technology/ Type: Development Kit
• For Use With/related Products: BTM411
• 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-BTM411

BTM410/411
Bluetooth
AT COMMAND SET
REFERENCE
42 www.lairdtech.com
®
AT Data Module
12. Factory Default UART Baud Rate
13. RI dependent Start-up Mode
14. Reset via BREAK
15. Append Bluetooth Address to Friendly name
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 Ú Factory Default Ú Via BREAK/CMD @ 9600
(Tested with version 6.7.2 of Ezurio Terminal)
The UART_RI line can be configured as an input and on power up its state can be used to force the
device into one of two modes, defining discoverability and connectability state. See description for
S Registers 565 to 569 inclusive for more details.
For example, the feature could allow a device to make an outgoing connection if RI is in one state,
and be ready for an incoming connection in the other.
The module can be reset by sending a BREAK signal. A BREAK signal exists when the module’s
UART_RX input is in a non-idle state (0v) for more than 125 milliseconds.
Ezurio Terminal provides a BREAK capability which can be used to reset a connected BTM device by
ticking and un-ticking the BRK field, see Figure 3.9.
If S Reg 593 is set to 1, then the last 6 hex digits of the Bluetooth address are automatically
appended to the friendly name. This allows multiple devices with the same name in a neighbourhood
to be differentiated.
Figure 3.9: BREAK capability in Ezurio Terminal
Laird Technologies