User's Manual

www.lairdtech.com

Laird Technologies

BTM510/511

Bluetooth

Multimedia Module

9. Maximum RF-Tx Power Level

The maximum RF transmit power level for all operation states (inquiring/connecting/in connection)

is controlled by S541/S542.

10. Manufacturing Info String

A string with manufacturing information can be retrieved by “ATI200”.

11. Bluetooth Version

The Bluetooth version can be queried by “ATI18”.

12. Legacy Issues (BT2.0)

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 rst (=pairing, BISM2: “AT+BTW<BdAddr>”). After successful pairing,

the connection can be initiated by the legacy device (BISM2: “ATD<BdAddr>”).

13. Factory Default UART Baud Rate

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 congure 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)

14. RI Dependent Start-Up Mode

The UART_RI line can be congured as an input and on power up its state can be used to force the

device into one of two modes, dening 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.

15. Reset via BREAK

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 eld, see Figure 3.35.

AT COMMAND SET

REFERENCE