Laird BTM410 User manual

1.
Version 3.0

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Bluetooth®AT Data Module
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REVISION HISTORY
REVISION HISTORY
Revision
Description
Version 1.0
Version 2.0
03/01/2012 –Initial Release
12/03/2012 –General updates and compliant with firmware v16.1.3.0
Version 3.0
04/13/2012 –Reformatting and general edits

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TABLE OF
CONTENTS
TABLE OF CONTENTS
1. Overview and Key Features ....................................................................4
2. Specifications..........................................................................................5
Detailed Specifications...............................................................................5
Pin Definitions...........................................................................................6
Operating Parameters ...............................................................................8
Voltage Specifications................................................................................8
3. AT Command Set Reference ...................................................................9
Introduction...............................................................................................9
Glossary of Terms....................................................................................10
Overview of the BTM Product Family........................................................11
BTM - AT Command Set ..........................................................................12
General AT Commands............................................................................13
AT Commands for S Registers.................................................................16
General S Registers................................................................................18
AT Commands for Inquiry ........................................................................18
Secure Simple Pairing (SSP) ...................................................................21
AT Commands for Legacy Pairing............................................................25
AT Commands Managing Trusted Devices ...............................................26
AT Commands for Serial Stream Oriented Profiles (SSO) .........................27
AT Commands for a Selected Peer Device...............................................31
Bluetooth Profiles ....................................................................................33
Hardware Units (BTM410 / 411)...............................................................38
Miscellaneous .........................................................................................40
4. Appendix ...............................................................................................49
General S Registers................................................................................49
ATI Commands........................................................................................57
Error Responses .....................................................................................59
List of UUIDs...........................................................................................61
References..............................................................................................62
5. FCC Regulatory Statements..................................................................63
BTM410 FCC and Industry Canada Statements .......................................63
BTM411 FCC and Industry Canada Statements........................................64
6. Declarations of Compliance..................................................................65
EU Declaration of Conformity –BTM410..................................................65
EU Declaration of Conformity –BTM411 ..................................................66
7. Bluetooth SIG Approvals.......................................................................67
8. Mechanical Drawings ............................................................................68
Development Kit Schematic.....................................................................73
9. Application Note for Surface Mount Modules.......................................75
Introduction.............................................................................................75
Shipping..................................................................................................75
Reflow Parameters..................................................................................76
10. Ordering Information.............................................................................77
Product Part Numbers.............................................................................77
General Comments .................................................................................77

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OVERVIEW
AND KEY FEATURES
1. OVERVIEW AND KEY FEATURES
The BTM410 and BTM411 Bluetooth® modules from Laird Technologies have been designed to meet the
needs of developers who wish to add robust, short range Bluetooth data connectivity to their products.
They are based on the market leading Cambridge Silicon Radio BC04 chipset, providing exceptionally low
power consumption with outstanding range. They support the latest Bluetooth® Version 2.1
Specification, providing the important advantage of Secure Simple Pairing, which improves security and
enhances the ease of use for end customers.
With physical sizes as small as 12.5 x 18.0mm and best of class, low-power operation, these modules are
the ideal choice for applications where designers need both performance and minimum size. For
maximum flexibility in systems integration, the modules are designed to support a separate power
supply for I/O.
To aid product development and integration, Laird Technologies has integrated a complete Bluetooth
protocol stack within the modules, including support for the Bluetooth Serial Port Profile. The modules
are fully qualified as Bluetooth End Products, allowing designers to integrate them within their own
products with no further Bluetooth Qualification. They can then list and promote their products on the
Bluetooth website free of charge.
A comprehensive AT command interface is included, which simplifies firmware integration. Combined
with a low cost developer’s kit, this ensures that the choice of Laird Technologies Bluetooth modules
guarantees the fastest route to market.
FEATURES AND BENEFITS
Bluetooth® v2.1+EDR
Adaptive Frequency Hopping to
cope with interference from other wireless devices
Secure Simple Pairing support
External or internal antenna options
Comprehensive AT interface for simple programming
Bluetooth® END Product Qualified
Compact size
Class 2 output –4dBm
Low power operation
UART interface
PCM and SCO for external codec
GPIO lines under AT control
Support for Serial Port Profile
Wi-Fi co-existence
APPLICATIONS
Embedded Devices
Phone Accessories
Security Devices
Medical and Wellness Devices
Automotive Applications
Bluetooth Advertising
ePOS

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2. SPECIFICATIONS
Detailed Specifications
Table 2-1: Detailed specifications
Categories
Feature
Implementation
Wireless Specification
Bluetooth®
Version 2.1+EDR
Transmit Class
Class 2
Frequency
2.402 –2.480 GHz
Channels
79 channels Frequency Hopping
Adaptive Frequency Hopping
Max Transmit Power
+4 dBm at antenna pad –BTM410
+4 dBmi from integrated antenna –BTM411
Min Transmit Power
-27 dBm at antenna pad –BTM410
-27 dBmi from integrated antenna –BTM411
Receive Sensitivity
-84dBm
Range
30m
Data Transfer Rate
Up to 300 kbps
Antenna Modes
External Antenna
50 Ohm matched SMT pad –BTM410
Integrated Antenna
(option)
+0 dBi multilayer ceramic –BTM411
UART Interface
Serial Interface
RS-232 bi-directional for commands and data
16550 compatible
Baud Rate
Configurable from 1,200 to 921,600bps
Non-standard baud rates supported
Bits
8
Parity
Odd, even, none
Stop bits
1 or 2
Default Serial parameters
9600,n,8,1
Levels
Set by VDD_USB input
Modem Control
DTR, DSR, DCD, RI, RTS, CTS
General Purpose
Interface
I/O
8 general purpose I/O pins
Audio
Support
1 PCM channel @ 64kbps
SCO Channels
Support SCO and eSCO
PCM Interface
Configurable as master or slave
8 bit A-law
8 bit μ-law
13 bit linear
PCM Clock available when in slave mode
Protocols and
Firmware
Bluetooth Stack
V2.1 compliant. Fully integrated.
Profiles
GAP (Generic Access Profile)
SDP (Service Discovery Profile)
SPP (Serial Port Profile)
Firmware Upgrade
Available over UART
Connection Modes
Point to point (cable replacement)
Command Interface
AT Instructions set
Comprehensive control of connection and
module operation S Registers for non-volatile
storage of parameters
SPECIFICATIONS

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Categories
Feature
Implementation
Current Consumption
Data Transfer
Typically 32mA
Low Power Sniff Mode
Less than 2.5mA
Supply Voltage
Supply
3.0V –3.3V DC
I/O
1.7V –3.3V DC (independent of Supply)
USB & UART
1.7V –3.6V DC (independent of Supply)
Coexistence/
Compatibility
WLAN (802.11)
2-wire and 3-wire hardware coexistence
schemes supported
Connections
Interface
Surface Mount Pads
External Antenna
(BTM410)
Pad for 50 Ohm antenna
Physical
Dimensions
12.5mm x 18.0 x 3.4mm BTM410
12.5mm x 22.0mm x 3.4mm BTM411
Weight
3 grams
Environmental
Operating Temperature
-40°C to +85°C
Storage Temperature
-40°C to +85°C
Approvals
Bluetooth
Qualified as an END product
FCC
Limited Modular Approval (BTM410)
Full Modular Approval (BTM411)
CE & R&TTE
Meets CE and R&TTE requirements
Miscellaneous
Lead free
Lead-free and RoHS compliant
Warranty
12 Months
Development Tools
Development Kit
Development board and software tools
DVK-BTM410 Dev Kit with BTM410 module
DVK-BTM411 Dev Kit with BTM411 module
Pin Definitions
Table 2-2: Pin definitions
Signal
Description
Voltage Specification
1
Unused
2
GND
3
UART_CTS
Clear to Send I/P
VUSB
4
UART_RXD
Receive data I/P
VUSB
5
UART_RTS
Request to Send O/P
VUSB
6
UART_TXD
Transmit data O/P
VUSB
7
GND
8
SPI_CSB
SPI bus chip select I/P
VIO
9
SPI_MISO
SPI bus serial O/P
VIO
10
SPI_MOSI
SPI bus serial I/P
VIO
11
SPI_CLK
SPI bus clock I/P
VIO
12
VDD_USB
USB & UART supply voltage
13
VDD_IO
I/O supply voltage
14
VDD_IN
Main supply voltage
15
GND
16
PCM_IN
PCM data I/P
VIO
17
PCM_SYNC
PCM sync I/P
VIO
18
PCM_CLK
PCM clock I/P
VIO
19
PCM_OUT
PCM data O/P
VIO
20
RESET
Module reset I/P
See note 2
21
GPIO4
I/O for host - BT_Active / BT_State
VIO
SPECIFICATIONS

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Signal
Description
Voltage Specification
22
GPIO2 / UART_DCD
I/O for host
VIO
23
GND
24
Unused
25
Unused
See note 3
26
Unused
See note 3
27
Unused
See note 3
28
GND (BTM410 only)
See note 3
29
ANT (BTM410 only)
Antenna connection (50 ohm matched)
See note 3
30
GND (BTM410 only)
See note 3
31
Unused
See note 3
32
Unused
See note 3
33
Unused
See note 3
34
Unused
See note 3
35
Unused
See note 3
36
Unused
See note 3
37
Unused
See note 3
38
Unused
39
Unused
40
Unused
41
GND
42
GPIO1 / UART_RI
I/O for host
VIO
43
GPIO7 / UART_ DTR
I/O for host
VIO
44
GPIO8 / UART_DSR
I/O for host
VIO
45
GND
46
D-
Not used for AT module variants
VUSB
47
D+
Not used for AT module variants
VUSB
48
GPIO6
I/O for host - RF_Active
VIO
49
GPIO5
I/O for host - WLAN_Active
VIO
50
GPIO3
I/O for host - BT_Priority
VIO
Note: 1. Unused pins may have internal connections and must not be connected.
2. Reset input is active low. Input is pulled up to VDD_IN via 22k. Minimum reset pulse width is 5ms.
3. Pins 8 –11 (SPI related) are only for Laird internal production purposes.
4. Pins 25-37 should be left not connected on modules with integrated antenna.
PIN DEFINITIONS

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OPERATING
PARAMETERS
Operating Parameters
Table 2-3: Operating parameters
Recommended Operating Conditions
OPERATING CONDITION
MIN
MAX
VDD_USB
(USB compatibility not required)
1.7
3.6
VDD_USB
(USB compatibility required)
3.1
3.6
VDD_IO
1.7
3.3
VDD_IN
3.0
3.3
Voltage Specifications
Table 2-4: Voltage specifications (VUSB)
Logic Levels (VUSB)
INPUT VOLTAGE LEVELS
MIN
TYP
MAX
Vih
0.7VDD_USB
Vil 2.7<VDD_USB<3.0
1.7<VDD_USB<1.9
-0.4
-0.4
+0.8
-0.4
Output Voltage Levels (1.7<VDD_USB<1.9)
Voh (Iout = -4mA)
VDD_USB –0.4
Vol (Iout = 4mA)
0.4
Output Voltage Levels (2.7<VDD_USB<3.0)
Voh (Iout = -4mA)
VDD_USB –0.2
Vol (Iout = 4mA)
0.2
Note: VDD_USB must be connected to power the USB and UART interfaces.
Table 2-5: Voltage specifications (VIO)
Logic Levels (VIO)
INPUT VOLTAGE LEVELS
MIN
TYP
MAX
Vih
0.7VDD_IO
Vil 2.7<VDD_USB<3.0
1.7<VDD_USB<1.9
-0.4
-0.4
+0.8
-0.4
Output Voltage Levels (1.7 < VDD_IO < 1.9)
Voh (Iout = -4mA)
VDD_USB –0.4
Vol (Iout = 4mA)
0.4
Output Voltage Levels (2.7 < VDD_IO < 3.0)
Voh (Iout = -4mA)
VDD_USB –0.2
Vol (Iout = 4mA)
0.2

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AT COMMAND SET
REFERENCE
3. AT COMMAND SET REFERENCE
Introduction
This document describes the protocol used to control and configure the BTM Bluetooth device.
The protocol is similar to the industry standard Hayes AT protocol used in telephony modems which is
appropriate for cable replacement scenarios, as both types of devices are connection oriented.
Just like telephony modems, Laird Technologies’ devices power up in an unconnected state and will only
respond via the serial interface. In this state the device will not even respond to Bluetooth Inquiries.
Then, just like controlling a modem, the host can issue AT commands which map to various Bluetooth
activities. The configuration of the device can be saved, so that on a subsequent power up the device is
discoverable or automatically connects.
The device has a serial interface which can be configured for baud rates from 1200 up to 921600
(default setting is 9600) and an RF communications end point. The latter has a concept of connected
and unconnected modes and the former will have a concept of command and data modes. This leads to
the matrix of states shown below.
Table 3-1: Mode RF connections
RF Unconnected
RF Connected
Local Command Mode
OK
OK
Remote Command Mode
ILLEGAL
OK
Data Mode
ILLEGAL
OK
The combinations, ‘Data and RF Unconnected Mode’ and ‘Remote Command and RF Unconnected
Mode’ do not make sense and will be ignored.
Navigation between these states is done using the AT commands which are described in detail in
subsequent sections.

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AT COMMAND SET
REFERENCE
Glossary of Terms
Table 3-2: Glossary of Terms
Description
A2DP
:
Advanced Audio Distribution Profile
ACL
:
Asynchronous Connection-Oriented Link
ADC
:
Analogue to Digital Converter
AGHFP
:
Audio Gateway Hands-Free Profile
AT
:
Command prefix, ‘Attention’
AVRCP
:
Audio/Video Remote Control Profile
BISM
:
Bluetooth Intelligent Serial Module
CoD
:
Class Of Device (also referred to as “device class”)
Codec
:
Device capable of encoding / decoding an analogue / digital signal
DAC
:
Digital to Analogue Converter
DSP
:
Digital Signal Processor
DUN
:
Dial-Up Network Profile
EIR
:
Extended Inquiry Response
eSCO
:
Enhanced Synchronous Connection Oriented Link (used for Audio)
FTP
:
File Transfer Profile
GOEP
:
Generic Object Access Exchange Profile
GPIO
:
General Purpose Input Output
HF
:
Hands-free Role of Hands-free Profile (“Hands-free Unit”)
HFG
:
Audio Gateway Role of Hands-free Profile (“Hands-free Gateway”)
HFP
:
Hands Free Profile
HID
:
Human Interface Device Profile
HS
:
Headset Role of Headset Profile (“Headset”)
HSG
:
Audio Gateway Role of Headset Profile (“Headset Gateway”)
HSP
:
Headset Profile
I/O (IO)
:
Input/Output
Mic
:
Microphone
MITM
:
Man In The Middle
OPP
:
Object Push Profile
PBAP
:
Phone Book Access Profile
PT
:
PASS THROUGH Command
PWM
:
Pulse Width Modulation
SBC
:
Sub Band Codec
SCO
:
Synchronous Connection Oriented Link (used for Audio)
SLC
:
Service Level Connection
SPP
:
Serial Port Profile
SSO
:
Serial Stream Oriented
SSP
:
Secure Simple Pairing
SUI
:
SUBUNIT INFO Command
Sxxx
:
S-Register No. xxx
TDL
:
Trusted Device List
UART
:
Universal Asynchronous Receiver / Transmitter
UI
:
UNIT INFO Command

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AT COMMAND SET
REFERENCE
Overview of the BTM Product Family
Table 3-3: BTM 410 and 411 products
BTM410 / BTM411
Chipset
CSR BC4-Ext
Bluetooth version
2.1
Features
SSP, EIR, SCO (1), eSCO (1)
Profiles
SPP
(1) external codec required
Table 3-4: BTM 510 and 511 products
BTM510 / BTM511
Chipset
CSR BC5MM-Ext
Bluetooth version
2.1
Features
SSP, EIR, SCO, eSCO
Profiles
SPP, A2DP, AVRCP,HSP,HFP,DUN(DT)
Table 3-5: BTM 520 and 521 products
BTM520 / BTM521
Chipset
CSR BC5MM-Ext
Bluetooth version
2.1
Features
SSP, EIR, SCO, eSCO
Profiles
SPP, A2DP, AVRCP,HSP,HFP,DUN(DT)

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AT COMMAND SET
REFERENCE
BTM - AT Command Set
This section describes the AT Command Set for a BTM module. This section is structured in functional
groups of AT commands, related to module configuration, Bluetooth profiles, hardware units and
miscellaneous purposes.
Assumptions
1. All commands are terminated by the carriage return character 0x0D, which is represented
by the string <cr> in descriptions below this cannot be changed.
2. All responses from the BTM device have carriage return and linefeed characters preceding and
appending the response. These dual character sequences have the values 0x0D and 0x0A
respectively and shall be represented by the string <cr,lf>
3. All Bluetooth addresses are represented by a fixed 12 digit hexadecimal string, case insensitive.
4. All Bluetooth Device Class codes are represented by a fixed 6 digit hexadecimal string, case
insensitive.
5. All profile specific commands are identified by the prefix shown in Table 3-6.
Table 3-6: AT command prefix for profiles
Profile
Term
AT-Command Prefix
Serial Port Profile
SPP
AT+SP…
Command Syntax
The following syntax is employed throughout this document to describe optional or mandatory
parameters for AT commands.
<bd_addr>
A 12 character Bluetooth address consisting of ASCII characters ‘0’ to ‘9’,
‘A’ to ‘F’ and ‘a’ to ‘f’.
<devclass>
A 6 character Bluetooth device class consisting of ASCII characters ‘0’ to ‘9’,
‘A’ to ‘F’ and ‘a’ to ‘f’.
N
A positive integer value.
M
An integer value which could be positive or negative, which can be entered
as a decimal value or in hexadecimal if preceded by the ‘$’ character. E.g.
the value 1234 can also be entered as $4D2
<string>
A string delimited by double quotes. E.g. “Hello World”. The “ character
MUST be supplied as delimiters.
<uuid>
A 4 character UUID number consisting of ASCII characters ‘0’ to ‘9’, ‘A’ to
‘F’ and ‘a’ to ‘f’.

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AT COMMAND SET
REFERENCE
General AT Commands
1. AT
This command is used to check whether or not the module is available.
Response: <cr,lf>OK<cr,lf>
2. ATEn {Enable/Disable Echo}
This command enables or disables the echo of characters to the screen. A valid parameter value will
be written to S Register 506.
E0 … Disable echo.
E1 … Enable echo.
All other values of n will generate an error.
Response: <cr,lf>OK<cr,lf>
Or
Response: <cr,lf>ERROR nn<cr,lf>
3. ATZ<n> {Hardware Reset and emerge into boot mode ‘n’}
Forces the device through a hardware reset which means it will eventually come alive in the local
command and unconnected mode. This allows changes to the non-volatile memory to take effect.
The module will issue an OK response after the reset is complete and it is ready to receive
commands once again.
ATZ and ATZ0 signify reset and emerge into the current boot mode (see command ATI14). ATZ1 to
ATZ4 instructs the module to reset and then emerge into the appropriate boot mode. Note that S
Register 103 specifies the boot mode from cold.
Boot modes are required to configure some low level device settings which cannot be configured by
S registers and AT commands. Currently there are predefined settings defining the PCM data format
to be used with certain codec ICs (applies mainly to BC04).
Response after reset: <cr,lf>OK<cr,lf>
4. AT+BTC<devclasshex> {Set Device Class Code Temporarily}
This command is used to set the device class code which will be sent in subsequent inquiry
responses. It can be read back using the AT+BTC? Command, as described below.
<devclass> is a 6 digit hexadecimal number derived as per “Bluetooth Assigned Numbers” [3].
The 24 bits are made of 4 fields briefly described as follows (bit 0 corresponds to the least
significant bit):
Bits 0-1:
Format Type. This field currently only has a value of 00 (i.e. format type 1)
Bits 2-7:
Minor Device Class: The value of these 6 bits is interpreted differently based on
the Major Device Class stored in the next 5 bits.
Bits 8-12:
Major Device Class: 5 bits, refer to Figure 1 and Table 3 in “Bluetooth Assigned
Numbers” [3]
Bits 13-23:
Major Service Class: 11 bit field, used as a mask to define service classes, refer to
Figure 1 and Table 2 in “Bluetooth Assigned Numbers” [3]

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AT COMMAND SET
REFERENCE
AT COMMAND SET
REFERENCE
Laird Technologies devices do not map to any predefined Major Service Class or Major Device Class
and so the default devclass as shipped is 001F00, which means no Major Service Class and
“Unclassified” Major Device class.
Other examples of device class codes are displayed in Table 3-7:
Table 3-7: Device class codes
Code (Hexadecimal)
Name
Major Service
Major Device
Minor Device
0x001F00
Unclassified
None
Unclassified
n/a
0x200404
Headset
Audio
Audio
Headset
There is a tool available in the internet for creating a particular device class code: refer to [4]. A
device class set by AT+BTC becomes visible immediately but will be lost on next power cycle.
Response: <cr,lf>OK<cr,lf>
Or for an invalid <devclass> value (usually a value which is not 6 hexadecimal characters
long):
Response: <cr,lf>ERROR 08<cr,lf>
5. ATS515=<devclasshex> {Set Device Class Code Permanently}
S Register 515 is used to set the device class code permanently. Use AT&W to save the setting to
non-volatile memory. The new value will become visible on next power cycle which can be initiated
by ATZ. Refer to number 4 for more information about the device class code.
Response: <cr,lf>OK<cr,lf>
6. AT+BTC? {Read Device Class Code}
This command is used to read the current device class code.
Response: <cr,lf>123456
<cr,lf>OK<cr,lf>
7. AT+BTF=”<string>” {Set Friendly Name Temporarily}
This sets the friendly name of this device as seen by other devices. The new name becomes
immediately visible. Any name set by this command will be lost on next power cycle.
Please refer to S register 593 (Appendix Table 4-1) too.
Response: <cr,lf>OK<cr,lf>
8. AT+BTN=”<string>” {Set Friendly Name Permanently}
This sets the default friendly name of this device as seen by other devices. It will be stored in
non-volatile memory. The new name will become visible to other devices on next power cycle. Use
AT+BTF to make the name visible immediately. Use AT+BTN? To read it back. An empty string (“”)
will delete the string from non-volatile memory which will force the default name to be used which
is “Laird BTM 789012”.
The digits in the default friendly name represent the last 6 digits of the local Bluetooth address.
Please refer to S register 593 (Appendix Table 4-1) too. If a new value of S593 needs to be retained
permanently, save it to non-volatile memory by “AT&W”.
Response: <cr,lf>OK<cr,lf>

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AT COMMAND SET
REFERENCE
9. AT+BTN? {Read Friendly Name from Non-volatile Memory}
Read the default friendly name from non-volatile memory.
Response: <cr,lf>”My Friendly Name”<cr,lf>
<cr,lf>OK<cr,lf>
10. AT+BTF<bd_addr> {Get Remote Friendly Name}
This command gets the remote friendly name of the peer specified.
Response: <cr,lf><bd_addr>,”Friendly Name”
<cr,lf>OK<cr,lf>
11. AT+BTP {Make Device Discoverable and Connectable }
Make the device discoverable and connectable and wait for a connection from any device.
The setting remains valid until next reset or power cycle (unless not changed by any other AT
command subsequently). For permanent discoverable/connectable settings, please refer to S
Register 512.
Response: <cr,lf>OK<cr,lf>
12. AT+BTQ {Make Device Discoverable}
Make the device discoverable but not connectable. Being discoverable implies that this device will
respond to inquiries from other devices (inquiry scans enabled).
The setting remains valid until next reset or power cycle (unless not changed by any other AT
command subsequently). For permanent discoverable/connectable settings, please refer to S
Register 512.
Use AT+BTX to make the device not discoverable.
Response: <cr,lf>OK<cr,lf>
13. AT+BTG {Make Device Connectable}
Make the device connectable but not discoverable and wait for a connection from any device.
The setting remains valid until next reset or power cycle (unless not changed by any other AT
command subsequently). For permanent discoverable/connectable settings, please refer to S
Register 512.
Response: <cr,lf>OK<cr,lf>
14. AT+BTV<bd_addr>,<uuid> {SDP Query for Service }
This command is used to interrogate the SDP database of the peer device <bd_addr> for the
service
<uuid>. It results in an ACL connection and then an SDP transaction.
If the <uuid> service is present then
Response: <cr,lf>0
<cr,lf>OK<cr,lf>

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AT COMMAND SET
REFERENCE
If the <uuid> service is not present then
Response: <cr,lf>1
<cr,lf>OK<cr,lf>
If the device < bd_addr > cannot be reached, or is in non-connectable mode then
Response: <cr,lf>2
<cr,lf>OK<cr,lf>
If the SDP database is corrupt or invalid then
Response: <cr,lf>3
<cr,lf>OK<cr,lf>
If the device is not in idle mode then
Response: <cr,lf>4
<cr,lf>OK<cr,lf>
and in this case, the command AT+BTX may put the device into the correct idle mode.
15. ATIn {Information}
This will return the information about the Laird Technologies device and its status. Please refer to
Table 37 (Appendix Table 4-2) for a complete list of supported ATIn parameters.
For recognized values of n:
Response: <cr,lf>As Appropriate<cr,lf>OK<cr,lf>
For unrecognized values of n.
Response: <cr,lf>Laird Technologies Inc, UK, (c)2009<cr,lf>
AT Commands for S Registers
As with modems, the Bluetooth module employs a concept of registers which are used to store
parameters, such as escape sequence character, inquiry delay time etc.
For a list of general S registers please refer to Table 4-1 in the Appendix.
S registers associated with a particular profile or specific functions, are described in the appropriate
profile section of this document. The following AT commands allow the manipulation of S registers.
1. ATSn=m {Set S Register}
The value part ‘m’ can be entered as decimal or hexadecimal. A hexadecimal value is specified via a
‘$’ leading character. For example $1234 is a hexadecimal number.
When S register values are changed, the changes are not stored in non-volatile memory UNTIL the
AT&W command is used. Note that AT&W does not affect S registers 520 to 525 or 1000 to 1010 as
they are updated in non-volatile memory when the command is received.
2. ATSn? {Read S Register Value}
This will return the current value of register n.
For recognized values of n
Response: <cr,lf>As Appropriate<cr,lf>OK<cr,lf>
For unrecognized values of n
Response: <cr,lf>ERROR nn<cr,lf>

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3. ATSn=? {Read S Register –Valid Range}
This will return the valid range of values for register n.
For recognized values of n
Response: <cr,lf>Sn:(nnnn..mmmm)<cr,lf>OK<cr,lf>
For unrecognized values of n
Response: <cr,lf>ERROR nn<cr,lf>
4. AT&Fn {Set S Register Defaults}
This command will only work when the device is in local command and unconnected mode.
Depending on the value of ‘n’ it installs S Register values appropriate for various power modes,
ranging from minimum power consumption to maximum.
Legal values of ‘n’ are as per the following table. All other values of n will generate a syntax error
response. If ‘n’ is not specified then a default value of 0 is assumed where the baud rate is NOT
changed.
&F0 (Default)
Medium power consumption, UART baud rate unchanged
&F1
Minimum power consumption, UART baud rate set to 9600
&F2
Minimum power consumption, UART baud rate set to 38400
&F3
Minimum power consumption, UART baud rate set to 115200
&F4
Medium power consumption, UART baud rate set to 115200
&F5
Maximum power consumption, UART baud rate set to 115200
The new values are NOT updated in non-volatile memory until the AT&W command is sent to the
device.
Response: <cr,lf>OK<cr,lf>
Or
Response: <cr,lf>ERROR nn<cr,lf>
5. AT&F* {Clear Non-volatile Memory}
The AT&F* variant of the command installs values in S registers as per command AT&F4 and then all
other user parameters in non-volatile memory are erased. This means that the trusted device
database is cleared, and so are parameters related to the following commands: AT+BTR, AT+BTN,
AT+BTS.
Response: <cr,lf>OK<cr,lf>
Or
Response: <cr,lf>ERROR nn<cr,lf>
6. AT&F+ {Clear Non-volatile Memory}
This command erases all user parameters in non-volatile memory except S Registers 520 to 525.
This means that the trusted device database is cleared, and so are parameters related to the
following commands: AT+BTR, AT+BTN, AT+BTS.
Response: <cr,lf>OK<cr,lf>
Or
Response: <cr,lf>ERROR nn<cr,lf>

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7. AT&W {Write S Registers to Non-volatile Memory}
Writes current S Register values to non-volatile memory so that they are retained over a power
cycle.
Response: <cr,lf>OK<cr,lf>
Or
Response: <cr,lf>ERROR nn<cr,lf>
General S Registers
Please refer to the Appendix (Table 4-1) for a list of supported S Registers.
The main purpose of S Registers is to make the device configuration persistent. All S Registers can be
saved to non-volatile memory by AT&W.
In some cases, an AT command and an S register exist for one and the same setting. In the majority of
those cases the AT command’s setting will be lost on next power cycle whereas the S register can be
saved and is still available after power cycle. This rule applies to many but not to all of those cases.
AT Commands for Inquiry
1. AT+BTI <devclass> {Inquire}
This will make the device perform an inquiry for delay seconds and max number of unique
responses, where delay is defined by S register 517 and max is specified by S register 518.
The <devclass> is an optional parameter where the value specifies either a 6 digit device class code
or a 2 digit major device class. If it is not specified, the value is taken from S register 516.
When <devclass> is 6 hexadecimal characters long, it specifies an AND mask which is used to filter
inquiry responses. When <devclass> is 2 hexadecimal characters long, it forces the inquiry to filter
responses to devices that match their major device class code to this value –which can only be in
the range 00 to 1F.
The response format to AT+BTI is defined by S Register 330 by bitmask. This is device address,
device class, friendly name, receiver strength indicator and extended inquiry data. Please refer to
Table 3-8 and Table 3-9.
For S330=1:
Response: <cr,lf>12346789012
<cr,lf>12345678914
<cr,lf>OK<cr,lf>
A Bluetooth inquiry process is such that for a single inquiry request a device could respond many
times. To ensure that an address is sent to the host only once for a particular AT+BTI, an array of
addresses is created at the start of each AT+BTI and is filled as responses come in. This array of
addresses is stored in dynamic memory and as such if the memory allocation fails then the inquiry
procedure is aborted and in that case an error response is sent to the host. To clarify, a single
AT+BTI will never return the same Bluetooth address more than once, but as long as the responding
device is active, all AT+BTI commands will always return it.
As the inquiry process is driven by randomness, it is not guaranteed that each discoverable device is
always found on the first attempt. Sometimes more than one inquiry processes might be necessary
to find a particular device. The probability also depends on the inquiry scanning intervals of the
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The inquiry process can be speed up if the friendly name is not required (flag not set in S330) as
part of the inquiry response or if a <dev_class> filter is used.
Table 3-8: S Register 330 controlling inquiry response format
Bit
7
6
5
4
3
2
1
0
Reserved for future use
EIRD
RSSI
FN
COD
ADR
Default
0
0
0
0
0
0
0
1
Table 3-9: Field Descriptions for S Register 330
Field
Description
0 –ADR
1 –display Bluetooth device address on inquiry result
0 –do not display Bluetooth device address on inquiry result; if any further
bit is set, a comma is inserted as separator
1 –COD
1 –display class of device on inquiry result
0 –do not display class of device on inquiry result; if any further bit is set, a
comma is inserted as separator
2 –FN
1 –display friendly name on inquiry result
0 –do not display friendly name on inquiry result; if any further bit is set, a
comma is inserted as separator
3 –RSSI
1 –display RSSI value on inquiry result
0 –do not display RSSI value on inquiry result; if any further bit is set, a
comma is inserted as separator
4 –EIRD
1 –display eird on inquiry result
0 –do not display eird on inquiry result
Inquiry Response format
The format of an inquiry result will be:
<cr,lf><bd_addr>,<dev_class>,<friendly_name>,<rssi>,<eir_data><cr,lf>
<bd_addr> = 12 digit, hexadecimal;
<dev_class> = 6 digit, hexadecimal;
<friendly_name> = printable ASCII character, enclosed by ‘ “ ‘
<rssi> = signed 2 digits decimal
<eir_data> = printable ASCII character whenever possible, otherwise a byte is displayed as:
¬2 digit hexadecimal with preceding ‘\’, enclosed by ‘ “ ‘
For example, the data block 01 41 42 43 44 02 03 45 46 04 0A 0D will be presented as:
“\01ABCD\02\03456\04\0A\0D”
No validation is performed on incoming EIR data.
If a higher significant flag is set and a lower significant bit is not set in S 330, for each disabled
item a comma is printed.
Example: S330 = 9 (ADDR enabled, COD and FN disabled, RSSI enabled)
Inquiry Response:
<cr,lf>123456789012,,,-54
<cr,lf>123456789014,,,-54
<cr,lf>OK<cr,lf>

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2. AT+BTIV<devclass> { Inquire }
As per AT+BTI but the response comprises for all inquiry responses:
1. Bluetooth device address
2. Device class code
S register 330 is not referenced.
3. AT+BTIN<devclass> { Inquire }
As per AT+BTI but the response comprises for all inquiry responses:
1. Bluetooth device address
2. Device class code
3. Friendly name
S register 330 is not referenced.
4. AT+BTIR<devclass> { Inquire }
As per AT+BTI but the response comprises for all inquiry responses:
1. Bluetooth device address
2. Device class code
3. Friendly name
4. RSSI (receiver signal strength indicator)
S register 330 is not referenced.
5. AT+BTIE<devclass> { Inquire }
As per AT+BTI but the response comprises for all inquiry responses:
1. Bluetooth device address
2. Device class code
3. Friendly name
4. RSSI (receiver signal strength indicator)
5. Extended inquiry data
S register 330 is not referenced.
6. AT+BTE=”<EIR-Data>” {Set up outgoing EIR Data}
This command sets up outgoing EIR (extended inquiry response) data.
Format: <EIR-Data> = printable ASCII character whenever possible, otherwise a 2 digit hexadecimal
with preceding ‘\’ presenting one byte. Please note that the given data is written to baseband as it
is (raw data) and no checks on the data format is performed. Hence, the user is responsible for
writing data that corresponds to the extended inquiry response data format as described in the
Bluetooth Specification Version 2.1 + EDR [1], vol3, Part C –Generic Access Profile, 8 Extended
Inquiry Response Data Format (page 1305 in the .pdf-file).
Response: <cr,lf>OK<cr,lf>