Ezurio 520B User Manual
BTM520/521
DATA MODULE
USER MANUAL
www.lairdtech.com
Innovative Technology
for a Connected World
BTM520/521
Bluetooth® Multimedia Plus Module
TABLE OF
CONTENTS
CONTENTS
BTM520/521 Bluetooth® Module ..3
Overview .............................................. 3
BTM520/521 Key Features ................... 3
Specications ................................5
Detailed Specications ......................... 5
Pin Out ................................................. 6
Operating Parameters ...................9
Voltage Specications .......................... 9
Notes ................................................. 10
Conguring the BTM520/521 ......11
References ......................................... 11
Glossary of Terms ............................... 12
AT Command Set .............................. 13
Assumptions ...................................... 13
Commands ........................................ 13
General AT Commands ..................... 13
General Bluetooth® Control ............... 24
Hardware Unit Control ....................... 30
Bluetooth® Proles ............................. 32
Secure Simple Pairing ......................... 39
Link Key Management ....................... 39
Miscellaneous...................................... 40
Appendix ........................................... 41
BT-MM+ Unsolicited Messages .......... 41
BT-MM+ Error Responses ................... 41
Mechanical Drawings ..................43
Mechanical Details ............................. 43
Recommended PCB Footprint ............ 43
Diagrams ............................................ 44
Ordering Information ..................47
Product Part Numbers ........................ 47
General Comments ............................ 47
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2
Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
OVERVIEW AND
KEY FEATURES
The BTM520 and BTM521 are the most advanced low power, multimedia Bluetooth
modules on the market. They have been designed by Laird Technologies to meet the needs
of developers who require the ultimate Bluetooth audio performance and exibility, along
with fast time to market. The modules include everything needed for a fully qualied
and functional Bluetooth multimedia application. As well as providing best in class radio
performance, range and power consumption, they support all of the functionality to run
Cambridge Silicon Radio’s Road Tunes and Blue Tunes development environments. They
support the latest Bluetooth Version 2.1+EDR Specication, providing the important advantage
of Secure Simple Pairing, which improves security and enhances the ease of use for end
customers. The BTM521, with an integrated high performance multilayer ceramic antenna
can achieve open eld ranges in excess of 300 metres.
The modules include a 16 bit stereo codec and microphone input to support both stereo and
mono applications, with the ability to drive 16Ω stereo speakers. They also contain all of
the necessary audio ltration and biasing components, so that the module only requires the
addition of speakers, microphone and push buttons to make a complete implementation.
The modules contain a full, integrated Bluetooth stack along with SPP, HFP 1.5, HSP, AVRCP
and A2DP proles, all of which have been qualied, so that no further Bluetooth qualication
is required. For users with more complex applications, additional proles will be available for
le transfer, object exchange, dial up networking, messaging and phone book control. Future
support also includes the Health Device Prole, making this the ideal module for development
of Continua compliant medical devices. Because these modules are pre-qualied, customers
using these modules can list and promote their products on the Bluetooth website free of
charge.
The BTM520 and BTM 521 modules include an embedded 32 bit, 64 MIPS DSP core within
the BC05, which is integrated with the Bluetooth functionality and which allows designers
to add signicant product enhancements. These include features such as echo cancellation,
noise reduction and audio enhancement using additional soft codecs. 16MB of ash memory
is available within the module, so that complex functionality can be included. DSP routines are
licensable from a number of specialist partners. Typical applications for these modules include
Bluetooth headsets, Bluetooth stereo headsets, VoIP phones, automotive products, wireless
audio links and medical / healthcare devices.
To speed product development and integration, Laird Technologies has developed a
comprehensive AT command interface, which simplies application development and includes
support for audio and headset functionality. It provides access to GPIO pins, allowing these
to be mapped for direct connection to actuator buttons on headsets. Combined with a low
cost developer’s kit, this ensures that the choice of Laird Technologies Bluetooth modules
guarantees the fastest route to market.
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3
Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
OVERVIEW AND
KEY FEATURES
FEATURES
• Fully featured Bluetooth multimedia module
• Supports CSR Road Tunes and Blue
Tunes applications
• Bluetooth v2.1+EDR
• Supports mono and stereo
headset applications
• Ideal for medical applications using health
device prole
• Adaptive Frequency Hopping to cope with
interference from other wireless devices
• 32bit Kalimba DSP for enhanced
audio applications
• Support for Secure Simple Pairing
• External or internal antenna options
• HSP, HFP, A2DP and AVRCP audio proles
• Future support for OBEX, DUN, FTP, HDP
proles for additional functionality
• 16 bit stereo codec and microphone input
• Integrated audio ampliers for driving
16Ω speakers
• Comprehensive AT interface for
simple programming
• Bluetooth END Product Qualied
• Compact Size
• Class 1 output – 8dBm (typical)
• Low power operation
• Wi-Fi Coexistence Hardware Support
APPLICATION AREAS
• High Quality Stereo Headsets
• Mono Voice Headsets
• Hands-free devices
• Wireless Audio Cable Replacement
• MP3 and music players
• Medical and Healthcare Devices
• Phone Accessories
• VoIP products
• Cordless Headsets
• Automotive Applications
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Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
SPECIFICATIONS
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5
CATEGORIES FEATURE IMPLEMENTATION
Wireless Specication
Antenna Modes
UART Interface
General Purpose Interface
Audio
Protocols & Firmware
Standards Supported Bluetooth® v2.1 + EDR
Transmit Class Class 1
Frequency 2.402 – 2.480 GHz
Channels 79 channels Frequency Hopping
Max Transmit Power +8 dBm (typical) @ antenna pad – BTM520
Min Transmit Power -27 dBm @ antenna pad – BTM520
Receive Sensitivity Better than -86 dBm
Data Transfer rate Up to 300kbps
Range > 300 metres free space (Data)
External Antenna 50 Ohm U.FL – BTM520
Integrated Antenna +2dB multilayer ceramic – BTM521
Serial Interface RS-232 bi-directional for commands and data
Baud Rate Congurable from 1,200 to 921,600bps
Bits 8
Parity Odd, even, none
Stop bits 1 or 2
Default Serial parameters 9600,n,8,1
Levels 1.7 - 3.6V CMOS (independent of Vcc)
Modem Control RTS, CTS
I/O 16 general purpose I/O pins
ADC 2 x ADC
I2S Stereo Audio Digital Interface Bus
PCM Shared with I2S
SPDIF Shared with I2S
LED Two dedicated
Codec Integrated stereo codec with -95dB SNR for DAC
Ampliers Direct drive for 16Ω speakers On board lters
Microphone Input with bias for low noise microphone On board lters
Sample Rates (DAC & ADC) 8, 11.025, 16, 22.05, 32 & 44.1kHz
Bluetooth® Stack V2.1 compliant. Fully integrated.
Proles GAP (Generic Access Prole)
Protocols RFCOMM
Firmware Upgrade Available over UART
Adaptive Frequency Hopping
+10 dBmi (typical) from integrated antenna – BTM521 (provisional)
-27 dBmi from integrated antenna – BTM521 (provisional)
16550 compatible
Non-standard baud rates supported
DTR, DSR, DCD, RI
SDP (Service Discovery Prole)
SPP (Serial Port Prole)
HSP
HFP – Audio Gateway and Handsfree
A2DP – Source and Sink
AVRCP – Target and Controller
SCO/eSCO
FTP Client (future release)
DI (future release)
GOEP (future release)
PBAP (future release)
MAP (future release)
HDP (future release)
AVCTP
AVDTP
OBEX (future release)
MCAP (future release)
†
†
Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
SPECIFICATIONS
CATEGORIES FEATURE IMPLEMENTATION
Command Interface AT Instruction set Comprehensive control of connection and module operation,
Additional Support All I/O available for CSR Road Tunes and Blue Tunes applications
DSP Kalimba DSP Integrated in BC05 32bit, 64MIPS, 16Mbps Flash Memory
Applications Available from partners
Current Consumption Data Transfer Typically < 70mA (including speaker drive)
Low Power Sniff Mode Less than 1.5mA
Supply Voltage Supply 3.0V – 4.2V DC
I/O 1.7V – 3.6V DC
Coexistence / Compatibility WLAN (802.11) 2, 3 and 5-wire hardware coexistence schemes supported
Connections External Antenna (option) Pad for 50 Ohm antenna – BTM520
Interface Surface Mount Pads
Physical Dimensions 20.0mm x 36.0mm x 4.9mm
Weight 3 grams
Environmental Operating Temperature -30°C to +70°C
Storage Temperature -40°C to +85°C
Approvals Bluetooth
FCC Meets FCC requirements
CE & R&TTE Meets CE and R&TTE requirements
Miscellaneous Lead free Lead-free and RoHS compliant
Warranty 12 Months
®
including extensions for Audio control.
Direct mapping of GPIO to audio functions, e.g. Play, Volume, etc.
S Registers for non-volatile storage of parameters
(shared)
Qualied as an END product
Modular Approval (Integrated Antenna option – BTM521)
Development Tools Development Kit Development board and software tools
†Modem control pins and GPIO are shared
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6
Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
SPECIFICATIONS
PIN OUT
PIN SIGNAL DESCRIPTION VOLTAGE
SPECIFICATION
1 PCM_IN PCM Data I/P VPADS
2 PCM_OUT PCM Data O/P VPADS
3 PCM_SYNC PCM Sync I/P VPADS
4 PCM_CLK PCM CLK I/P VPADS
5 GND
6 SPI_MOSI SPI bus serial I/P VPADS
7 SPI_CSB SPI bus chip select I/P VPADS
8 SPI_MISO SPI bus serial O/P VPADS
9 SPI_CLK SPI bus clock I/P VPADS
10 LED_EXT1 Host I/O Open Drain
11 LED_EXT0 Host I/O Open Drain
12 PIO0 / RX_ENABLE VIO
13 PIO1 / TX_ENABLE VIO
14 GND
15 VDD_PADS VPADS supply
16 VDD_PIO VIO supply
17 VDD_IN Main supply
18 GND
19 AUDIO_GND
20 SPKR_B_P Speaker, channel B+ (right) – Note 3
21 SPKR_B_N Speaker, channel B- (right) – Note 3
22 SPKR_A_P Speaker, channel A+ (left) – Note 3
23 SPKR_A_N Speaker, channel A- (left) – Note 3
24 MIC_BIAS Microphone bias – Note 4
25 MIC_BN_C Microphone, channel A+ (left) – Note 4
26 MIC_BP_C Microphone, channel A- (left) – Note 4
27 MIC_AP_C Microphone, channel B- (right) – Note 4
28 MIC_AN_C Microphone, channel B+ (right) – Note 4
29 Unused
30 Unused
31 Unused
32 Unused
33 Unused
34 Unused
35 Unused
36 Unused
37 Unused
38 Unused
39 Unused
40 Unused
41 Unused
42 Unused
43 Unused
44 Unused
45 Unused
46 Unused
47 Unused
48 Unused
49 Unused
50 Unused
51 Unused
52 Unused
53 Unused
54 Unused
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Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
SPECIFICATIONS
PIN OUT (continued)
PIN SIGNAL DESCRIPTION VOLTAGE
SPECIFICATION
55 Unused
56 Unused
57 Unused
58 PIO3 / USB_VSENSE VIO
59 PIO14 / CSB Host I/O VPADS
60 AUX_DAC VIO
61 PIO4 Host I/O VIO
62 PIO5 / BT_STATE / BT_PROR-
ITY
63 PIO7 / RF_ACTIVE Host I/O / BT Co-existence VPADS
64 PIO15 Host I/O VPADS
65 PIO12 / SCL Host I/O VPADS
66 GND
67 AIO1 ADC Input, 10 bit 0-1.5V input range
68 PIO10 / DSR Host I/O VPADS
69 PIO11 / DTR Host I/O VPADS
70 AIO0 ADC Input, 10 bit 0-1.5V input range
71 PIO9 / DCD Host I/O VPADS
72 PIO13 / SDA Host I/O VPADS
73 PIO8 / RI Host I/O VPADS
74 PIO6 / WLAN_ACTIVE Host I/O / BT Co-existence VPADS
75 GND
76 USB_D- VUSB
77 USB_D+ VUSB
78 PIO2 / USB_PULL_UP VIO
79 VDD_USB VUSB supply
80 VREGENABLE_H Main regulator enable – pull high for correct operation
81 GND
82 UART_RTS Request to Send O/P VUSB
83 UART_CTS Clear to Send I/P VUSB
84 UART_TX Transmit data O/P VUSB
85 UART_RX Receive data I/P VUSB
86 Reset Module reset I/P (active low) – Note 1 VPADS
Host I/O / BT Co-existence VPADS
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Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
OPERATING
PARAMETERS
OPERATING PARAMETERS
RECOMMENDED OPERATING CONDITIONS
Operating Condition Min Max
VDD_USB
(USB compatibility not required)
VDD_USB
(USB compatibility required)
VDD_IO 1.7 3.6
VDD_PADS 1.7 3.6
VDD_IN 3.0 3.3
1.7 3.6
3.1 3.6
VOLTAGE SPECIFICATIONS
LOGIC LEVELS (VUSB)
Input Voltage Levels Min Typ Max
V
ih
V
il
Output Voltage Levels
Voh (Iout = -4mA) 0.75VDD_USB VDD_USB
Vol (Iout = 4mA) 0 0.125
LOGIC LEVELS (VIO)
Input Voltage Levels Min Typ Max
V
ih
V
il
Output Voltage Levels
Voh (Iout = -4mA) 0.75VDD_IO VDD_IO
Vol (Iout = 4mA) 0 0.125
0.625VDD_USB VDD_USB+0.3
-0.3 0.25VDD_USB
0.625VDD_IO VDD_IO+0.3
-0.3 0.25VDD_IO
LOGIC LEVELS (VPADS)
Input Voltage Levels Min Typ Max
V
ih
V
il
Output Voltage Levels
Voh (Iout = -4mA) 0.75VDD_PADS VDD_PADS
Vol (Iout = 4mA) 0 0.125
0.625VDD_PADS VDD_PADS+0.3
-0.3 0.25VDD_PADS
LOGIC LEVELS (VUSB – USB TERMINALS D+, D-)
Input Voltage Levels Min Typ Max
V
ih
V
il
Output Voltage Levels (to correctly terminated USB cable)
Voh 2.8 VDD_USB
V
ol
0.7VDD_USB
0.3VDD_USB
0 0.2
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Laird Technologies
BTM520/521
AC
AC
Single ended Double ended
VDD
Module External Circuit
R
MIC_AP
MIC_AN
Module
External Circuit
MIC_BIAS
15 nH
15 pF
15 nH
15 pF
Bluetooth® Multimedia Plus Module
OPERATING
PARAMETERS
Note: 1. Reset input is active low. Input is pulled up to VDD_PADS via 22k.
Minimum reset pulse width is 5ms.
2. LED drive pins are open drain outputs and hence the external circuit
to the right should be used.
The voltage on the module pad should be maintained below 0.5V
in which case the Ron of the FET is around 20Ω. Provided that this
condition is met, then the current owing through the diode is:
F
led
I
VDD - V
=
R + 20
Where VF is the forward bias voltage of the LED.
3. The speaker output is capable of driving loads with a minimum
impedance of 16Ω directly.
4. The audio inputs can operate in either line input mode or microphone
mode. The input circuit has a two stage amplier – the rst stage
provides a xed 24dB gain and the second a variable gain of
between -3dB and 18dB. If an input gain of less than 24dB is selected,
then the rst stage is switched out and the module is operating in line
input mode.
When operating in microphone mode the
microphone should be biased as follows:
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10
The input impedance on the microphone inputs (in microphone mode) is typically 6kΩ. In order to
maintain the regulation on the MIC_BIAS pin, the current drawn must be in the range 0.2 – 1.23mA.
If the resistor draws less current than this then an additional resistor to ground must be added to
pre-load the microphone output. The audio input is designed for use with inputs of between 1μA
and 10μA at 94dB SPL. If the biasing resistors are set to 1kΩ this implies a microphone with a
sensitivity in the range -40dBV to -60dBV.
When operating in line input mode, the input can be connected directly to the module input pins
in either single or double ended conguration as follows:
Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
CONFIGURING
THE BTM520/521
INTRODUCTION
This document describes the protocol used to control and congure the BT-MM+ Bluetooth device.
The AT commands described in the document apply to rmware releases from V14.0.9 onwards.
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 powers 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 command set is extensive enough to allow a host to make connections which are authenticated and/or
encrypted or not authenticated and/or encrypted or any combination of these. Commands 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 congured 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.
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.
REFERENCES
[1] “AT Command Set”
[2] “BlueLab_v4.0_Release_Note.pdf”
[3] “Audio/Video Distribution Transport Protocol Specication” Rev.V12, 16/04/2007
[4] “Advanced Audio Distribution Prole Specication” Rev. V12, 16/04/2007
[5] “Audio/Video Remote Control Prole” Revision V14r00, 26/06/2008
[6] “Software Release Note Stereo Headset SDK Q3 2007 RC3.1” CS-117522-RNP1, CSR
[7] “Stereo Headset SDK Q3 2007 User Guide” CSR, CS-116451-UGP1, CSR, December2007
[8] “Bluetooth Specication Version 2.1 + EDR [vol3]”, 26 July 2007
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Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
CONFIGURING
THE BTM520/521
Glossary of Terms
DESCRIPTION
A2DP : Advanced Audio Distribution Prole
ADC : Analogue to Digital Converter
AGHFP : Audio Gateway Hands-Free Prole
AT : Command prex, ‘Attention’
AVRCP : Audio/Video Remote Control Prole
BISM : Bluetooth Intelligent Serial Module
Codec : Device capable of encoding / decoding an analogue / digital signal
DAC : Digital to Analogue Converter
DSP : Digital Signal Processor
DUN : Dial-Up Network Prole
FTP : File Transfer Prole
GOEP : Generic Object Access Exchange Prole
GPIO : General Purpose Input Output
HFP : Hands Free Prole
HID : Human Interface Device Prole
I/O (IO) : Input/Output
Mic : Microphone
OPP : Object Push Prole
PBAP : Phone Book Access Prole
PWM : Pulse Width Modulation
Sxxx : S-Register No. xxx
SBC : Sub Band Codec
SPP : Serial Port Prole
TBD : To Be Determined
UART : Universal Asynchronous Receiver / Transmitter
PT : PASS THROUGH Command
UI : UNIT INFO Command
SUI : SUBUNIT INFO Command
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Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
CONFIGURING
THE BTM520/521
AT Command Set
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 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 xed 12 digit hexadecimal string, case insensitive.
4. All Bluetooth Device Class codes are represented by a xed 6 digit hexadecimal string, case insensitive.
Commands
The following syntax is employed throughput 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’.
General AT Commands
1. AT
Used to check the module is available.
Response: <cr,lf>OK<cr,lf>
2. ATA {Answer Call}
Accept an incoming connection, which is indicated by the unsolicited string
<cr,lf>RING 123456789012<cr,lf> every second. 123456789012 is the Bluetooth address of
the connecting device.
Response: <cr,lf>CONNECT 123456789012<cr,lf>
3. ATD<bd_addr>,<uuid> {Make Outgoing Connection}
Make a connection to device with Bluetooth address <bd_addr> and SPP prole <uuid>.
The <uuid> is an optional parameter which species the UUID of the prole server to attach to,
and if not supplied then the default UUID from S Register 101 is used. As this is a device
which utilizes the RFCOMM layer as described in the Bluetooth specication, it necessarily implies
that only proles based on RFCOMM can be accessed.
The timeout is specied by S register 505.
Response: <cr,lf>CONNECT 123456789012<cr,lf>
Or <cr,lf>NO CARRIER<cr,lf>
Due to a known issue in the Bluetooth RFCOMM stack, it is not possible to make more than
65525 outgoing connections in a single power up session. Therefore if that number is exceeded,
then the connection attempt will fail with the following response:-
Response: <cr,lf>CALL LIMIT
Or <cr,lf>NO CARRIER<cr,lf>
In that case, issuing an ATZ to reset the device will reset the count to 0 and more connections
are possible.
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Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
CONFIGURING
THE BTM520/521
The following RFCOMM based UUIDs are dened in the Bluetooth Specication:-
PROFILE NAME UUID
Serial Port 0x1101
LAN Access Using PPP 0x1102
Dialup Networking 0x1103
IrMC Sync 0x1104
OBEX Object Push 0x1105
OBEX File Transfer 0x1106
IrMC Sync Command 0x1107
Headset 0x1108
Cordless Telephony 0x1109
Intercom 0x1110
Fax 0x1111
Audio Gateway 0x1112
WAP 0x1113
WAP_CLIENT 0x1114
4. ATDL {Remake Connection}
Make a connection with the same device and service as that specied in the most recent ATD
command. An error will be returned if the ‘L’ modier is specied AND a Bluetooth address.
If both ‘L’ and ‘R’ modiers are specied then an error will be returned.
Response: <cr,lf>CONNECT 123456789012 AE<cr,lf>
Or <cr,lf>NO CARRIER<cr,lf>
5.ATDR{MakeConnectiontopeerspeciedinAT+BTR}
Make a SPP connection with the device address specied in the most recent AT+BTR command.
The service is as specied in S Register 101. An error will be returned if the ‘R’ modier is specied
AND a Bluetooth address.
If both ‘R’ and ‘L’ modiers are specied then an error will be returned.
Response: <cr,lf>CONNECT 123456789012 AE<cr,lf>
Or <cr,lf>NO CARRIER<cr,lf>
6. 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>
7. ATH {Drop Connection}
Drop an existing connection or reject an incoming connection indicated by unsolicited RING messages.
Response: <cr,lf>NO CARRIER<cr,lf>
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Laird Technologies
BTM520/521
Bluetooth® Multimedia Plus Module
CONFIGURING
THE BTM520/521
8. ATSn=m {Set S Register}
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, as listed in detail below.
The value part ‘m’ can be entered as decimal or hexadecimal. A hexadecimal value is specied 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.
Table 3-1: S-Register List
REGISTER DEFAULT RANGE COMMENT
S0 1 -1..15 Number of RING indication before automatically answering an incoming
S2 0x5E 0x20..0x7E
S12 100 40..5000 Escape sequence guard time in milliseconds, with a granularity of 20ms. New
S100 15 0..15 Number of RING indications before an auto disconnection is initiated. A value
S101 $1101 0..$ffff UUID of default SPP based prole when not specied explicitly in the ATD
S102 1 1..0x7FF Denes a set of bits masks for enabling prole servers. Values can be ORed.
S103 1 1..7 Boot Mode on cold boot.
S126 ? 0 .. 0xFFFF Primer for changing to Multipoint mode
S127 ? 0 .. 0xFFFF 0x100 for At mode
S300 1 0..2 Set A2DP role:
S301 1 0..2 Set AVRCP role:
connection. A value of 0 disables autoanswer. If -1, then autoanswer on one
RING and do NOT send RING/CONNECT response to the host. This emulates a
serial cable replacement situation
Setting values >= 0, resets S Register 504 to 0 and <0 forces 504 to 1.
If S0 <> 0 and S100 <> 0 then S0 must be < S100. If a value is entered which
violates this rule, then ERROR 29 is sent in response.
If S504 =1 then this register will return -1, regardless of the actual value
stored in non-volatile memory.
Escape sequence character. It is not ‘+’ by default as a Bluetooth® serial link
can be used to connect to a mobile phone which exposes an AT command
set, which will in turn use ‘+’ as default. So if both used ‘+’ there will be
confusion. 0x5e is the character ‘^’.
values are rounded down to the nearest 20ms multiple
of 0 disables this feature.
If S0 <> 0 and S100 <> 0 then S0 must be < S100. If a value is entered which
violates this rule, then ERROR 29 is sent in response.
command.
0x001 is Serial Port Prole
0x080 is A2DP
0x100 is AVRCP
0x200 for Multipoint mode
Other values are reserved
0 is feature not set
1 is A2DP Sink (default)
2 is A2DP Source
0 is feature disabled
1 is Control (CT) (default)
2 is Target (TG)
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