Ezurio 511B User Manual

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BTM510/511 MULTIMEDIA MODULE

USER MANUAL

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Innovative Technology for a Connected World

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BTM510/511

Bluetooth® Multimedia Module

TABLE OF CONTENTS

CONTENTS

BTM510/511 Bluetooth® Module ..3

Overview .............................................. 3

BTM510/511 Key Features

Specications ................................4

Detailed Specications ......................... 4

Pin Denitions

...................................... 6

Operating Parameters ...................8

Voltage Specications .......................... 8

Notes for PCB Layout

Conguring the BTM510/511 ........9

References ........................................... 9

Glossary of Terms AT Command Set Assumptions Commands General AT Commands

............................... 10

.............................. 11

...................................... 11

........................................ 11

................... 3

........................... 8

..................... 11

General Bluetooth Hardware Unit Control Bluetooth Secure Simple Pairing Link Key Management

Miscellaneous...................................... 38

Appendix BT-MM Unsolicited Messages BT-MM Error Responses

........................................... 39

Control ............... 22

....................... 28

Proles ............................. 30

......................... 37

....................... 37

............ 39

..................... 39

Mechanical Drawings ..................41

Mechanical Details ............................. 41

Recommended PCB Footprint Diagrams

............................................ 42

............ 41

Ordering Information ..................45

Product Part Numbers ........................ 45

General Comments

............................ 45

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BTM510/511

Bluetooth® Multimedia Module

OVERVIEW AND KEY FEATURES

The BTM510 and BTM511 are low-power Bluetooth® modules designed for adding robust audio and voice capabilities. Based on the market-leading Cambridge Silicon Radio BC05 chipset, these modules provide exceptionally low power consumption with outstanding range. Supporting the latest Bluetooth Version 2.1+EDR specication, these modules provide the important advantage of secure simple pairing that improves security and enhances easy use.

At only 14mm x 20mm, the compact size of the BTM510 makes it ideal for battery-powered or headset form factor audio and voice devices. With a 16-bit stereo codec and microphone inputs to support both stereo and mono applications, these modules also contain a full, integrated Bluetooth-qualied stack along with SPP, HFP 1.5, HSP, AVRCP, and A2DP

proles. Customers using these modules may list and promote their products free of charge

on the Bluetooth website.

The BTM510/511 modules include an embedded 32-bit, 64-MIPS DSP core within the BC05. This is integrated with the Bluetooth functionality which allows designers to add signicant product enhancements including features such as echo cancellation, noise reduction, and

audio enhancement using additional soft codecs. The availability of the 16MB of ash memory

in the module allows complex functionality to be included. DSP routines can be licensed through a number of specialist partners. Typical applications for these modules include Bluetooth stereo headsets, VoIP phones, and wireless audio links.

To speed product development and integration, Laird Technologies has developed a

comprehensive AT command interface that simplies application development, including

support for audio and headset functionality. Access to GPIO pins allows mapping for direct connection to actuator buttons on headsets. Combined with a low-cost development kit, Laird Technologies’ Bluetooth

FEATURES

• Fully featured Bluetooth® multimedia module

• Bluetooth® v2.1+EDR

• Supports mono and stereo

headset applications

• 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 proles

• 16-bit stereo codec and microphone input

• Integrated audio ampliers for driving

stereo speaker

• Comprehensive AT interface for simple programming

• Bluetooth END product qualied

• Compact size

• Class 2 output – 4dBm

• Low power operation

• Wi-Fi co-existence hardware support

modules provide faster time to market.

APPLICATION AREAS

• High-quality stereo headsets

• Mono voice headsets

• Hands-free devices

• Wireless audio cable replacement

• MP3 and music players

• Phone accessories

• VoIP products

• Cordless headsets

• Automotive

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BTM510/511

Bluetooth® Multimedia Module

SPECIFICATIONS

CATEGORIES FEATURE IMPLEMENTATION

Wireless Specication Standards Supported Bluetooth® v2.1 + EDR

Transmit Class Class 2

Frequency 2.402 – 2.480 GHz

Channels 79 channels Frequency Hopping Adaptive Frequency Hopping

Max Transmit Power +4 dBm @ antenna pad – BTM510

Min Transmit Power -27 dBm @ antenna pad – BTM510

Receive Sensitivity Better than -86 dBm

Data Transfer rate Up to 300kbps

Range Up to 50 meters free space (Data)

Antenna Modes External Antenna 50 Ohm matched SMT pad – BTM510

Integrated Antenna +0dB (provisional) multilayer ceramic – BTM511

UART Interface Serial Interface RS-232 bi-directional for commands and data 16550 compat-

Baud Rate Congurable from 1,200 to 921,600bps

Bits 8

Parity Odd, even, none

Stop bits 1 or 2

Default Serial parameters 9,600,n,8,1

Levels Set by VDD_USB pin

Modem Control DTR, DSR, DCD, RI, RTS, CTS

General Purpose Interface I/O 8 general purpose I/O pins

S Stereo Audio Digital Interface Bus

LED Two

Audio Codec Integrated stereo codec with -95dB SNR for DAC

Ampliers Direct drive for 22Ω Mono Speaker / 44Ω Stereo Speakers

Microphone Input with bias for low noise microphone

Sample Rates (DAC & ADC) 8, 11.025, 16, 22.05, 32 & 44.1kHz

Protocols & Firmware Bluetooth

Proles GAP (Generic Access Prole)

Protocols RFCOMM

Firmware Upgrade Available over UART

Stack V2.1 compliant. Fully integrated.

+4 dBmi from integrated antenna – BTM511 (provisional)

-27 dBmi from integrated antenna – BTM511 (provisional)

ible

Non-standard baud rates supported

SDP (Service Discovery Prole) SPP (Serial Port Prole)

HSP

HFP – Audio Gateway and Handsfree A2DP – Source and Sink AVRCP – Target and Controller

AVCTP AVDTP

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BTM510/511

Bluetooth® Multimedia Module

SPECIFICATIONS

CATEGORIES FEATURE IMPLEMENTATION

Command Interface AT Instruction set Comprehensive control of connection and module operation,

DSP Kalimba DSP Integrated in BC05 32bit, 64MIPS, 16Mbps Flash Memory

Applications Available from partners

Current Consumption Data Transfer Typically < 35mA

Stereo Music Typically < 70mA (including speaker drive)

Low Power Sniff Mode Less than 1.5mA

Supply Voltage Supply 3.0V – 3.6V DC

I/O 1.7V – 3.6V DC

USB 1.7V – 3.6V DC

Coexistence / Compatibility WLAN (802.11) 2-wire and 3-wire hardware coexistence schemes supported

Connections External Antenna (option) Pad for 50 Ohm antenna – BTM510

Interface Surface Mount Pads

Physical Dimensions 14.0mm x 20.0 x 1.6mm - BTM510

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 within EU requirements 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)

14.0mm x 26.0mm x 1.6mm - BTM511 (provisional)

Qualied as an END product

Modular Approval (Integrated Antenna option – BTM511)

Development Tools Development Kit Development board and software tools

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BTM510/511

Bluetooth® Multimedia Module

SPECIFICATIONS

PIN SIGNAL DESCRIPTION VOLTAGE

SPECIFICATION

1 PIO15 / DTR Host I/O VIO 2 PIO5/BT_STATE/BT_PRIORITY Host I/O, BT Co-existence VIO 3 PCM_IN PCM Data I/P VIO 4 PCM_OUT PCM Data O/P VIO 5 PCM_SYNC PCM Sync I/P VIO 6 PCM_CLK PCM CLK I/P VIO 7 LED_EXT1 Host I/O See Note 2 8 LED_EXT0 Host I/O See Note 2

9 GND 10 VDD_USB USB supply voltage 11 VDD_IO I/O supply voltage 12 VDD_IN Main supply voltage 13 GND 14 SPI_CSB SPI bus chip select I/P VIO 15 SPI_MISO SPI bus serial O/P VIO 16 SPI_CLK SPI bus clock I/P VIO 17 SPI_MOSI SPI bus serial I/P VIO 18 PIO2/DSR Host I/O VIO 19 PIO3/RI Host I/O VIO 20 PIO1/DCD Host I/O VIO 21 PIO0/BT_ACTIVE Host I/O, BT Co-existence VIO 22 GND 23 AUDIO_GND Audio ground 24 SPKR_A_N Speaker, channel A- (left) See note 3 25 SPKR_A_P Speaker, channel A+ (left) See note 3 26 SPKR_B_N Speaker, channel B- (right) See note 3 27 SPKR_B_P Speaker, channel B+ (right) See note 3 28 MIC_BIAS Microphone bias See note 4 29 MIC_BP_C Microphone, channel A- (left) See note 4 30 MIC_BN_C Microphone, channel A+ (left) See note 4 31 MIC_AP_C Microphone, channel B- (right) See note 4 32 MIC_AN_C Microphone, channel B+ (right) See note 4 33 Unused 34 ANT Antenna connection – BTM510 (50 ohm matched) 35 Unused 36 Unused 37 Unused 38 Unused 39 Unused 40 Unused 41 Unused 42 Unused 43 Unused 44 Unused 45 USB_D- VUSB 46 USB_D+ VUSB 47 GND 48 UART_RTS Request to Send O/P VUSB 49 UART_CTS Clear to Send I/P VUSB 50 UART_TX Transmit data O/P VUSB 51 UART_RX Receive data I/P VUSB 52 PIO7/RF_ACTIVE Host I/O, BT Co-existence VIO 53 PIO6/WLAN_ACTIVE Host I/O, BT Co-existence VIO 54 Reset Module reset I/P See Note 1

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BTM510/511

MIC_AP

MIC_AN

Module

External Circuit

MIC_BIAS

15nH

15pF

15nH

15pF

Single ended Double e n ded

VDD

Module External Circuit

Bluetooth® Multimedia Module

SPECIFICATIONS

Note: 1. Reset input is active low. Input is pulled up to VDD_IN 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:

led

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 amplier – 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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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 microphone 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.

The low pass lter elements formed by the inductor and capacitor are required to eliminate RF pick up on the microphone inputs and should be placed as close to the module as possible.

When operating in line input mode, the input can be connected directly to the module input pins

in either single or double ended conguration as follows:

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BTM510/511

Bluetooth® Multimedia Module

OPERATING PARAMETERS

RECOMMENDED OPERATING CONDITIONS

Operating Condition Min Max

VDD_USB

(USB compatibility not required)

VDD_USB

(USB compatibility required)

VDD_IO 1.7 3.3 VDD_IN 3.0 3.6

1.7 3.6

3.1 3.6

VOLTAGE SPECIFICATIONS

LOGIC LEVELS (VUSB)

Input Voltage Levels Min Typ Max

Output Voltage Levels

(Iout = -4mA) 0.75VDD_USB VDD_USB

(Iout = 4mA) 0 0.125

LOGIC LEVELS (VIO)

Input Voltage Levels Min Typ Max

Output Voltage Levels

(Iout = -4mA) 0.75VDD_IO VDD_IO

(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 (VUSB – USB TERMINALS D+, D-)

Input Voltage Levels Min Typ Max

Output Voltage Levels (to correctly terminated USB cable)

2.8 VDD_USB

0.7VDD_USB

0.3VDD_USB

0 0.2

NOTES FOR PCB LAYOUT:

1. The RF output pin must be matched to a 50Ω strip-line or coplanar waveguide on the antenna-less version (BTM510).

2. Ensure that there are no exposed conductors under the module to avoid shorts to the test points on the module underside.

3. ThePCBfootprintisprovidedforguidanceonly.UsersmaywishtomodifythePCBlanddimensionstosuittheirspecic

manufacturing or process.

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BTM510/511

Bluetooth® Multimedia Module

AT COMMAND SET REFERENCE

INTRODUCTION

This document describes the protocol used to control and congure 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 conguration 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 congured 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.

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BTM510/511

Bluetooth® Multimedia Module

AT COMMAND SET REFERENCE

GLOSSARY OF TERMS

Description

A2DP : Advanced Audio Distribution Prole

ACL : Asynchronous Connection-Oriented Link

ADC : Analogue to Digital Converter

AGHFP : Audio Gateway Hands-Free Prole

AT : Command prex, ‘Attention’

AVRCP : Audio/Video Remote Control Prole

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 Prole

EIR : Extended Inquiry Response

eSCO : Enhanced Synchronous Connection Oriented Link (used for Audio)

FTP : File Transfer Prole

GOEP : Generic Object Access Exchange Prole

GPIO : General Purpose Input Output

HF : Hands-free Role of Hands-free Prole (“Hands-free Unit”)

HFG : Audio Gateway Role of Hands-free Prole (“Hands-free Gateway”)

HFP : Hands Free Prole

HID : Human Interface Device Prole

HS : Headset Role of Headset Prole (“Headset”)

HSG : Audio Gateway Role of Headset Prole (“Headset Gateway”)

HSP : Headset Prole

I/O (IO) : Input/Output

Mic : Microphone

MITM : Man In The Middle

OPP : Object Push Prole

PBAP : Phone Book Access Prole

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 Prole

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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BTM510/511

Bluetooth® Multimedia Module

AT COMMAND SET REFERENCE

OVERVIEW OF THE BTM PRODUCT FAMILY

BTM410 / BTM411

Chipset CSR BC4-Ext

Bluetooth version 2.1

Features SSP, EIR, SCO (1), eSCO (1)

Proles SPP

(1) external codec required

BTM510 / BTM511

Chipset CSR BC5MM-Ext

Bluetooth version 2.1

Features SSP, EIR, SCO, eSCO

Proles SPP, A2DP, AVRCP,HSP,HFP,DUN(DT)

BTM520 / BTM521

Chipset CSR BC5MM-Ext

Bluetooth version 2.1

Features SSP, EIR, SCO, eSCO

Proles SPP, A2DP, AVRCP,HSP,HFP,DUN(DT)

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BTM510/511

Bluetooth® Multimedia Module

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 conguration, Bluetooth proles, 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 xed 12 digit hexadecimal string, case insensitive.

4. All Bluetooth Device Class codes are represented by a xed six digit hexadecimal string, case insensitive.

5. All prole specic commands are identied by the prex shown in Table 3.1

Prole Term AT-Command Prex

Serial Port Prole SPP AT+SP…

Advanced Audio Distribution Prole A2DP AT+AP…

Audio/Video Remote Control Prole AVRCP AT+AV…

Headset Prole HSP AT+HS…

Hands-Free Prole HFP AT+HF…

Dial-Up Network Prole DUN AT+DU…

Table 3.1: AT Command prex for proles

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 six 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

<string> A string delimited by double quotes, e.g., “Hello World”. The “ character MUST be supplied as delimiters.

<uuid> A four character UUID number consisting of ASCII characters ‘0’ to ‘9’, ‘A’ to ‘F’ and ‘a’ to ‘f’.

in hexadecimal if preceded by the ‘$’ character, e.g., the value 1234 can also be entered as $4D2.

General AT Commands

1. AT

Used to check 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>

Response: <cr,lf>ERROR nn<cr,lf>

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BTM510/511

Bluetooth® Multimedia Module

AT COMMAND SET REFERENCE

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

species the boot mode from cold.

Boot modes are required to congure some low level device settings which cannot be congured by S registers and AT commands. Currently there are predened settings dening 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<devclass

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 six digit hexadecimal number derived as per “Bluetooth Assigned Numbers” [8].

The 24 bits are made of four elds briey described as follows (bit 0 corresponds to the least signicant bit):-

Bits 0-1: Format Type. This eld currently only has a value of 00 (i.e.,

Bits 2-7: Minor Device Class: The value of these six bits is interpreted

Bits 8-12: Major Device Class: Five bits, refer to Figure 1 and Table 3 in

Bits 13-23: Major Service Class: 11 bit eld, used as a mask to dene

> {Set Device Class Code Temporarily}

hex

format type 1).

differently based on the Major Device Class stored in the next

ve bits.

“Bluetooth Assigned Numbers” [8].

service classes, refer to Figure 1 and Table 2 in “Bluetooth Assigned Numbers” [8].

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Laird Technologies devices do not map to any predened Major Service Class or Major Device Class and so the default devclass as shipped is 001F00, which means no Major Service Class and “Unclassied”

Major Device class.

Other examples of device class codes are follows:

Code (Hexadecimal) Name Major Service Major Device Minor Device

0x001F00 Unclassied None Unclassied n/a

0x200404 Headset Audio Audio Headset

There is a tool available in the Internet for creating a particular device class code: refer to [9].

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=<devclass

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>

> {Set Device Class Code Permanently}

hex

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BTM510/511

Bluetooth® Multimedia Module

AT COMMAND SET REFERENCE

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 (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 six digits of the local Bluetooth address.

Please refer to S register 593 (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>

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 specied.

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>

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BTM510/511

Bluetooth® Multimedia Module

AT COMMAND SET REFERENCE

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>

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 4.2 (Appendix) 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.

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 page 17 and Table 4.1.

S registers associated with a particular prole or specic functions, are described in the appropriate prole 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 specied 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 specied 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>

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>

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>

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>

Response: <cr,lf>ERROR nn<cr,lf>

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General S Registers

Please refer to Appendix, Table 4.1 for a list of supported S Registers.

The main purpose of S Registers is to make the device conguration 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 dened by S register 517 and max is specied by S register 518.

The <devclass> is an optional parameter where the value species either a six digit device class code or a two digit major device class. If it is not specied, the value is taken from S register 516.

When <devclass> is six hexadecimal characters long, it species an AND mask which is used to lter inquiry responses. When <devclass> is two hexadecimal characters long, it forces the inquiry to lter 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 dened by S Register 330 by bitmask. This is device address, device class, friendly name, receiver strength indicator and extended inquiry data. Please refer to Figure 3.1 and Table 3.2.

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 lled 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 rst attempt. Sometimes more than one inquiry processes might be necessary to nd a particular device. The probability also depends on the inquiry scanning intervals of the device

being searched for.

The inquiry process can be sped up if the friendly name is not required (ag not set in S330) as part of the inquiry response or if a <dev_class> lter is used.

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Bit 7 6 5 4 3 2 1 0

Reserved for future usage EIRD RSSI FN COD ADR

Default 0 0 0 0 0 0 0 1

Figure 3.1: S Register 330 controlling inquiry response format

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

Table 3.2: Field Descriptions for S Register 330

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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> = six digit, hexadecimal;

<friendly_name> = printable ASCII character, enclosed by ‘ “ ‘

<rssi> = signed two 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 signicant ag is set and a lower signicant 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>

2. AT+BTIV<devclass> { Inquire }

As per AT+BTI but the response comprises for all inquiry responses:

1. the Bluetooth device address

2. device class code

S register 330 is not referenced.

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3. AT+BTIN<devclass> { Inquire }

As per AT+BTI but the response comprises for all inquiry responses:

1. the 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. the 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. the 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.

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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 two 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

Specication Version 2.1 + EDR [1], vol3, Part C – Generic Access Prole, 8 Extended Inquiry Response Data Format (page 1305 in the .pdf-le).

Response: <cr,lf>OK<cr,lf>

7. AT+BTE? {Query Outgoing EIR Data}

This command prints the outgoing EIR data that is currently set up

Response:

<cr,lf>

<EIR-Data>

<cr,lf>OK<cr,lf>

Secure Simple Pairing (SSP)

Secure Simple Pairing (SSP) has been introduced since Bluetooth 2.1 + EDR. It aims to increase the security

provided by a Bluetooth link whilst making the pairing process more user friendly.

There are white papers about SSP available through the Internet (provided by the Bluetooth SIG and other companies), explaining the mechanisms and backgrounds of SSP. They can be found by searching the Internet for, e.g., “Bluetooth Secure Simple Pairing”. Please familiarize with those documents to get a better understanding

of SSP and the following settings.

1. Security Level (S320)

The security level is dened in the BT2.1+EDR specication [1], vol3, Generic Access Prole (Table 5.7). There are 4 Levels providing different levels of security:

Security Level Characteristics Comment

Level 3 • MITM protection (MITM = “Man in the

Middle” attack)

• Encryption

• User interaction

Level 2 • No MITM protection

• Encryption

Level 1 • No MITM protection

• (No) Encryption (1)

• Minimal user interaction

Level 0 • No MITM protection

• No Encryption

• Minimal user interaction

(1) Although encryption is not necessary for security level 1, encryption will always be enabled because this specication mandates encryption for all services other than SDP (service discovery).

Table 3.3: Security Levels

The security level is dened by S Register 320 and is referenced at boot time only. Hence the register must be saved by “AT&W “ and the module must be power cycled (or “ATZ”) subsequently.

S320 = 3 will overwrite the setting of S Register 322 (enable MITM).

The security level will remain the same until next power cycle and is valid for all proles and services of the module. For SDP (service discovery prole), security level 0 is always assigned internally.

High security

Medium Security

Low Security

Permitted only for service discovery

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2. IO-Capability (S321)

S-Register 321 denes the IO-capability of the device. The setting is used for IO-capability negotiations prior to SSP in order to identify whether the IO-capabilities of both devices are sufcient for MITM protection (if required). Table 3.4 lists possible values.

S321 IO-Capability Comment

0 Display only The device has the capability to display or communicate a

six digit decimal number.

1 Display yes no The device has the capability to display or communicate

a six digit decimal number and at least two buttons that can be easily mapped to ‘yes’ and ’no’ or a mechanism

whereby the user can indicate either ‘yes’ or ‘no’ (e.g., pressing a button within a certain time limit).

2 Keyboard only The device has a numeric keyboard that can input

numbers ‘0’ through ‘9’ and a conrmation. The device

has also at least two buttons that can be easily mapped to ‘yes’ and ’no’ or a mechanism whereby the user can

indicate either ‘yes’ or ‘no’ (e.g., pressing a button within a certain time limit).

3 No input no output The device does not have the ability to indicate ‘yes’ or

‘no’, and the device does not have the ability to display or communicate a 6 digit decimal number.

4 Reject IO-Cap requests IO-capability requests prior to SSP are rejected.

Table 3.4: IO capabilities

3. Force Man-In-The-Middle Protection (MITM, S322)

Protection against MITM-attacks can be enabled by S332. This S-Register only applies if the security level (S320) is less than 3. In case of security level (S320) = 3, MITM protection is always enabled and this S 322 is ignored.

A new value written to S322 applies immediately. No power cycle is required.

A link key created with MITM protection is named “authenticated link key”.

A link key created without MITM protection is named “unauthenticated link key”.

4. Disable Legacy Pairing (S323)

If the remote device is a legacy device (BT2.0 or earlier), legacy pairing with usage of PIN codes will be initiated. Legacy Pairing can be disabled by S-Register 323 = 1. Then pairing with legacy devices

will always fail.

5. SSP Timeout (S324)

The SSP timeout [s] is dened by S-Register 324. The timeout must be at least 60s to meet the BT specication requirements [1]. This time is required to be sufcient for the user to compare or read

and input a 6 digit number. A time of 90 seconds is recommended which is the default value.

6. SSP Input Commands

Table 3.5 lists all AT commands related to SSP input operations.

AT Command Operation Comment

AT+BTBY Accept pairing request Representing ‘yes’ input

AT+BTBN Reject pairing request Representing ‘no’ input

AT+BTB012345 Enter six digit passkey displayed by remote device Representing keyboard input

Table 3.5: SSP Input commands

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7. AT+BTW<bd_addr> {Initiate SSP}

This command initiates secure simple pairing (dedicated bonding) with a device whose Bluetooth address is <bd_addr>. The correct term for this command’s action with respect to the Bluetooth

specication 2.1+EDR [1] is “Dedicated Bonding”.

Dedicated bonding means the exchange of link keys (pairing) without creating a connection to a particular prole or service immediately.

The remote device must be a Bluetooth 2.1 device, otherwise (BT2.0 or earlier) legacy pairing will occur automatically if S323=0. For legacy pairing please refer to page 23.

The “OK” response is sent immediately on receipt of the AT+BTW command. Depending on the

combination of IO-capabilities of both devices, one of the asynchronous messages from Table 3.7 might appear during the pairing process. Please refer to that table for the required actions.

On pairing completion, an unsolicited message in the form PAIR n <bd_addr> will be sent to the host.

8. S Registers for Secure Simple Pairing

The following table lists all S Registers for Secure Simple Pairing. For the registers’ details please refer to their descriptions above.

S320 2 1..3 Security Level: see [1], vol3, Generic Access Prole - Table 5.7

needs subsequent ‘AT&W’ and power cycle to take effect value = 3 overwrites S322

S321 1 0..4 Set IO capability:

0 – display only 1 – display yes no 2 – keyboard only 3 – no input no output 4 – reject IO-cap requests

S322 0 0..1 Force man-in-the-middle-protection (MITM):

0 – disabled 1 – enabled referenced only if security level (S320) < 3

S323 0 0..1 Disable legacy (pre-BT2.1) Pairing:

0 – legacy pairing enabled 1 – legacy pairing disabled

S324 90 1..255 Secure Simple Pairing timeout in s

This value must be at least 60 in order to meet the recom-

mendation of BT2.1 specication

Table 3.6: S-Registers for Secure Simple Pairing (SSP)

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9. Asynchronous SSP Messages

Table 3.7 lists asynchronous messages which occur if MITM is enabled. The actually sent message depends on the combination of the IO capabilities of both ends. The combination of IO capabilities

of both devices can also be insufcient for MITM protection. In that case the pairing will fail (PAIR 2 <BdAddr>). Please refer Table 5.6 in BT2.1+EDR specication [1], vol3, Generic Access Prole for sufcient combinations of IO-capabilities for MITM (=authenticated link key).

Message Action / Comment

PAIR ? <BdAddr>,”<friendlyname>”,<Passkey>

Example:

PAIR ? 0016A4000002,”Laird BTM

000002”,863611

PASSKEY ? <BdAddr>,”<friendlyname>”

Example:

PASSKEY ? 0016A4000001,”Laird BTM 000001”

PAIR N <BdAddr>,”<friendlyname>”,<Passkey>

Example:

PASSKEY N 0016A4000002,”Laird BTM

000002”,164585

PAIR 0 <BdAddr> <nn> Successfully paired with device of <BdAddr>.

PAIR 1 <BdAddr> Pairing timeout

PAIR 2 <BdAddr> Pairing failed

PAIR 3 <BdAddr> Pairing failed (too many repeat attempts)

PAIR 4 <BdAddr> Pairing rejected by remote device

PAIR 5 <BdAddr> Pairing failed (unit keys not supported)

PAIR 6 <BdAddr> Pairing failed (SSP not supported)

PAIR 7 <BdAddr> Pairing failed (already busy with pairing)

(1) If both devices have a “KeyboardOnly” capability, no pass key can be displayed. In that case, the

user is required to invent and enter the identical 6 digit numeric passkey at both ends.

Table 3.7: Asynchronous messages for SSP

Passkey compare request:

Expecting the user to compare the passkey

displayed on both ends and to conrm a match by “AT+BTBY” at both ends or reject by “AT+BTBN” if passkey does not match.

Passkey request:

Expecting the user to enter the passkey displayed by the remote device. Use AT+BTB<passkey>,

example: AT+BTB012345 *see(1) below

Passkey notication:

Display BdAddr, friendly name and passkey to user.

Expecting the user to enter the passkey from this message at the remote device’s numeric keyboard.

<nn> (optional) indicates the status of automatic storage to trusted device list. Value 0 = success; settings controlled by S325 to S328.

Please refer to section 2.3, page 82.

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10. Known SSP Issues

a.) General Bonding (automatic pairing on link setup if devices have not been paired previously) does not work with legacy devices (BT2.0 and earlier). If the remote device is BT2.0 or earlier, initiate dedicated bonding (AT+BTW<BdAddr>) prior to connection establishment.

b.) Outgoing General Bonding (automatic pairing on link setup if devices have not been paired previously) with MITM does not work with two BTM devices, because any UART input on the initiating device is not accepted until the link has been established. Workaround: initiate dedicated bonding (AT+BTW<BdAddr>) prior to connection establishment.

c.) If the link key of previously paired devices is not available any more in the remote device but still available in the trusted device list (TDL) of the local device (query by AT+BTT?), pairing will fail. In that

case remove the device address from the local TDL using AT+BTD<BdAddr> and reinitiate pairing

from the local device (AT+BTW<Bd_addr>).

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AT Commands for Legacy Pairing

1. AT+BTW<bd_addr> {Initiate Pairing}

Provided the remote device is a Bluetooth 2.0 device or earlier and legacy pairing is not disabled (S323 = 0), this command is used to initiate legacy pairing with the device with <bd_addr>. Legacy pairing refers to the mechanism of entering an identical PIN key on both ends.

If the PIN is required (if not set earlier by AT+BTK=”<PIN>”), asynchronous indications will be sent to the host in the form PIN? <bd_addr> where the address conrms the device with which the pairing

is to be performed. To supply a PIN, use the AT+BTK command.

For a successful pairing, the link key is stored in a volatile cache which is overwritten every time a

new pairing is initiated using this command. If S register 325=1, the link key is automatically saved to the non-volatile trusted device list. Otherwise (S325=0) the link key can be added to the trusted

device list by AT+BTT. Please refer to below under AT Commands managing Trusted Devices for further AT commands related to trusted device list.

The “OK” response is sent immediately on receipt of the AT+BTW command. On pairing completion, an unsolicited message will be sent to the host which will be in the form PAIR n <bd_addr>.

If AT+BTI or AT+BTP or AT+BTG or AT+BTQ or ATD is issued between the AT+BTW command and the subsequent PAIR asynchronous response, then an ERROR response will be sent to those commands as the device is not in a mode from where such commands can be actioned.

Response: <cr,lf>OK<cr,lf>

2. AT+BTK=”<string>” {Set Passkey}

This command is used to provide a PIN passkey. The PIN is stored in non-volatile memory for future use. If this command is used as response to a “PIN? 12345678” asynchronous message, the PIN provided by this command will not be stored in non-volatile memory.

Specifying an empty string deletes the PIN from the non-volatile memory. The string length must be in the range 0 to 8, otherwise an error will be returned.

Response: <cr,lf>OK<cr,lf>

3. Legacy Pairing – Asynchronous Messages

PIN?

This response is sent to the host during a pairing negotiation.

The fully qualied string is PIN? 012345678901 where 012345678901 is the Bluetooth address of the peer device. In response, the host must supply a pin code which is entered using the AT+BTK command.

If the peer does not supply the address in the message exchange, then the address is specied as 000000000000 – and the pairing will proceed as normal.

PAIR n <bd_addr>

This response is sent to the host on termination of a pairing process. If pairing was successful then ‘n’ = 0, if a timeout occurred then ‘n’=1 and for all other unsuccessful outcomes the value will be 2. The parameter <bd_addr> is the address of the peer device if available.

PAIR 0 <bd_addr> MM

This response is sent to the host on termination of a successful pairing process. The optional MM is

sent only if the according S Register 325..328 is set to 1 to automatically save the link key (see Section 2, page 82). The value MM indicates the result of the save operation and a value of 00 implies success,

otherwise the value corresponds to an error code.

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AT Commands Managing Trusted Devices

1. AT+BTT? {List Trusted Device}

This command is used to list the contents of the trusted device database. The link key is NOT displayed so the response is as shown below. If the list is empty then just the OK response is sent otherwise an OK is used to terminate the list. Use the command ATI6 to read the maximum size of the trusted device database.

Response: <cr,lf>12346789012

<cr,lf>12345678913

<cr,lf>12345678914

<cr,lf>OK<cr,lf>

2. AT+BTT {Add Trusted Device}

This command is used to store the cached link key in the non-volatile database. If the database is full, it will respond with an ERROR. If the device is already in the database, then the key is replaced. If the link key cache is empty, that is, a pairing has not been performed since the device was powered, then the response will be an ERROR.

Response: <cr,lf>OK<cr,lf>

Response: <cr,lf>ERROR<cr,lf>

3. AT+BTD<bd_addr> {Remove Trusted Device}

This command is used to remove the specied device from the list of trusted devices in the non-volatile database. If the device is not in the database, then the response will still be an OK.

Response: <cr,lf>OK<cr,lf>

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4. AT+BTD* {Remove All Trusted Devices}

This command is used to remove all devices from the trusted device list (TDL) in the non-volatile database. No conrmation will be asked for. So beware!!!

WARNING: If you make a connection, the link key gets cached in the underlying stack. So if you subsequently delete the key using AT+BTD* and immediately request a connection to the same device, then the connection will be established. To ensure this does not happen, send ATZ after the AT+BTD*.

Response: <cr,lf>OK<cr,lf>

5. AT+BTW? {List Cached Trusted Device}

This command is used to list the cached trusted device.

Response: <cr,lf>12346789012

<cr,lf>OK<cr,lf>

If the cache is empty the response is as follows.

Response: <cr,lf>OK<cr,lf>

AT Commands for Serial Stream Oriented Proles (SSO)

The Serial Port Prole (SSP) and the Dial-up Networking Prole (DUN) belong to the group of Serial Stream Oriented proles (SSO).

When activated, an SSO prole claims one UART for its data stream and assumes all data at the UART to be transmitted over or received from RF 1:1. Hence, as there is only one UART available on a BTM device, the UART is not available for other proles, services or module control purposes.

One approach of managing data and control over UART is to congure local command mode with S531=3.

In this mode, incoming RF data is presented by the asynchronous message RX<string>. Outgoing data is sent by ATX<string> or ATY<string>.

With this approach it is possible to manage several non-SSO connections (e.g., A2DP, AVRCP) and at maximum one SSO connection (SSP or DUN). An attempt to connect a second SSO prole while already

one SSO connected will result in Error 65.

Any incoming connection request to an SSO prole will be rejected if one SSO is already connected.

The following section describes AT- commands related to SSO-proles.

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AT COMMAND SET REFERENCE

1. ATX”<string>” {Send Data in Local Command and Connected Mode}

This command is used to send data to the remote device when in local command and connected mode.

The parameter <string> is any string not more than 29 characters long whereby a non-printable

character (\hh, see below) counts three characters. This restriction results from the maximum AT command length which is 34 (query by ATI15). The difference of 5 is caused by “ATX” (three characters) and the enclosing quotation marks (two characters).

If the maximum string length is exceeded, ERROR 05 (syntax error) will occur.

If a non-visual character is to be sent then insert the escape sequence \hh where hh are two hexadecimal digits. The three character sequence \hh will be converted into a single byte before transmission to the peer.

Response: <cr,lf>OK<cr,lf>

<cr,lf>ERROR 05<cr,lf> (e.g. <string> too long)

2. ATY”<string>” {Send Data in Local Command and Connected Mode}

This command is similar to ATX in syntax and functionality, except that the string is only copied to the output rf buffer. Only when an empty string is presented, all pending data in the output rf buffer

will be ushed out.

The parameter <string> is any string not more than 29 characters long whereby a non printable

If the maximum string length is exceeded, ERROR 05 (syntax error) will occur.

Response: <cr,lf>OK<cr,lf>

<cr,lf>ERROR 05<cr,lf> (e.g. <string> too long)

3. ^^^ {Enter Local Command Mode}

When in data and connected mode and when S 507 is set to 0 or 1, the host can force the device into a command and connected mode so that AT Commands can be issued to the device. The character in

this escape sequence is specied in the S2 register, so it can be changed. In addition, the escape sequence guard time is specied by S Register 12. By default the guard time is set to 100 milliseconds.

Leaving data mode by “^^^” has a severe penalty on data throughput, because each incoming character needs to be checked for ‘^’ with respect to the guard time.

Alternatively, a de-assertion of the DTR/DSR line can be used as the only trigger to leave data mode (S507=2). This gives a signicant higher data throughput because data is passed directly between UART and RF without character checking. Please refer to Section 6, page 26 for more information.

In modems this escape sequence is usually “+++”. “^^^” is specied to avoid confusion when the module is providing access to a modem.

Response: <cr,lf>OK<cr,lf>

4. !!! {Enter Remote Command Mode}

When in data and connected mode, the host can force the remote device into a command and connected mode so that AT Commands can be issued to the device remotely. The escape sequence guard time is specied by S Register 12 and is the same as per the ^^^ escape sequence. By default the guard time is set to 100 milliseconds. The remote device issues ATO as normal to return to data

mode (Refer to 5). For this command to be effective S Register 536 must be set to 1.

Response: <cr,lf>OK<cr,lf>

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5. ATO {Enter Data Mode} (letter ‘o’)

Return to data mode. Assume that the module is in data mode after OK is received. Responds with an error if there is no Bluetooth SSO connection.

Response:

<cr,lf> CONNECT 123456789012,<<cr,lf> (if it was an incoming connection)

<cr,lf> CONNECT 123456789012,><cr,lf> (if it was an outgoing connection)

Response: <cr,lf>ERROR nn<cr,lf>

6. Dropping SSO Connections

In a conventional telephony modem, a call is normally terminated by rst sending a +++ character sequence enveloped by an escape sequence guard time (of the order of 100 to 1000 milliseconds)

to enter local command and connected mode and then the ATH command.

Laird Technologies BTM devices provide a variety of ways of dropping a connection. One method is similar to the above, but instead a ^^^ character sequence is used. This is to eliminate ambiguity when a data call is in progress via a mobile phone which was established using the mobile phone’s Bluetooth AT modem. The second method involves the host dropping the DTR (DSR from the module’s viewpoint) handshaking line.

Being able to drop a connection using the escape sequence ^^^ has a severe penalty on data throughput. In fact, the data rate is of the order of 85kbps instead of about 300kbps. To cater for

this performance hit, the device’s connection drop capability is congurable to be in one of two modes.

One mode allows for a connection to be dropped using either method, and the other mode allows for a connection drop using the DTR method only. By default, the device is in the former mode. This mode

is selected using the S507 register (Appendix, Table 4.1).

To reiterate, the escape sequence is as follows:-

This means that even when a le transfer is occurring and it happens to be full of <Esc Chr> characters then it is not going to drop into command mode because, when transferring, a le it is going to happen as fast as possible and so the inter character gap is going to be signicantly shorter than the <Guard time>.

The <Esc Chr> character can be changed via the S2 register and the <Guard time> interval can be

specied via the S12 register (Appendix, Table 4.1).

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7. SSO - Asynchronous Messages

RX<string>

This response is sent to the host when the unit is in online-command mode and S Register 531 is set to 3 and data arrives from a peer.

If the data from the string contains non-visual characters (for example ASCII 0 to 31 and ASCII 128 to 255), then those characters are translated into a three character escape sequence starting with ‘\’.

For example the embedded <cr><lf> sequence would be sent as the six character string \0D\0A.

If the data contains the character ‘“’ then it is sent as \22.

If the data contains the character ‘\’ then it is sent as \5C.

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8. SSO – S Registers

The following table lists S registers for SSO proles.

S2 94 32..126 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.

94 is the character ‘^’.

S12 100 40..5000 Escape sequence guard time in milliseconds, with a

granularity of 20ms. New values are rounded down to the nearest 20ms multiple.

S507 0 0..2 When set to 0, a connection can be dropped using ^^^

escape sequence only and the state of DSR line is ignored. When set to 1, a connection can be dropped using EITHER the

^^^ escape sequence OR the DSR handshaking line. When set

to 2, a connection can only be dropped using a deassertion of DSR. Mode 2 provides for the highest data transfer rate.

If the status of the DSR line is to be conveyed to the remote device as a low bandwidth signal then this register MUST be set to 0, otherwise a deassertion of DSR will be seen as a request to drop the Bluetooth connection.

This register affects S Register 536 – see details of 536.

S531 0 0..4 Species the mode on connection establishment.

0 = Normal, that data is exchanged between UART and RF. 1 = LOCAL_COMMAND. UART input is parsed by the AT

interpreter and RF data is discarded. 2 = REMOTE_COMMAND. RF input is parsed by the AT

interpreter and UART data is discarded. If S Reg 536 is not 1 then this register cannot be set to 2 and an ERROR will be returned.

3 = LOCAL_COMMAND. UART input is parsed by the AT

interpreter and incoming RF data is sent to the host using the RX<string> asynchronous response.

4 = LOCAL_COMMAND and on the rf side, the gpio is automatically sent when there is a change in input (digital I/O cable replacement mode).

S536 0 0..1 When set to 1, a remote device can ‘capture’ the AT parser of

this unit by it sending this module an escape “!!!” sequence.

The inter character timing is set via S Register 12.

If S Register 507 is >= 2, then reading this register will always

return 0 and writing 1 will result in ERROR 33.

Table 3.8: S Registers for SSO proles

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AT Commands for a Selected Peer Device

This section describes AT commands to make the BTM Bluetooth device connectable for one particular remote device only or to connect to a particular remote device on reset or on power cycle automatically.

1. AT+BTP<bd_addr> {Make Device Discoverable and Selectively Connectable}

Make the BTM device discoverable (for all devices) and connectable for the device with the Bluetooth address <bd_addr> only. Connection requests from any other devices will be rejected.

If <bd_addr> is 000000000000 then incoming connections are accepted from any device, as per AT+BTP without an address.

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 and AT+BTM<bd_addr>

Response: <cr,lf>OK<cr,lf>

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2. AT+BTG<bd_addr> {Make Device Selectively Connectable Only}

Make the BTM device connectable for the device with the Bluetooth address <bd_addr> only. Connection requests from any other devices will be rejected.

If the specied address is 000000000000 then incoming connections are accepted from any device, is as per AT+BTP without an address.

The BTM device is not discoverable.

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 and

AT+BTM<bd_addr>

Response: <cr,lf>OK<cr,lf>

3. AT+BTM<bd_addr> {Set Incoming Peer Address}

This command is used to store a peer address for incoming connections in non-volatile memory. Only the device with Bluetooth address <bd_addr> will be permitted to make a connection to the BTM device. Connection requests from other devices will be rejected.

The new setting applies immediately and will retain over a power cycle (unless not changed by any other AT command subsequently).

When S register 512 = 3, 4, 6 or 7 then the BTM device will wait for an incoming connection from the peer address specied. If <bd_addr> is 000000000000, then incoming connections from any

devices are permitted.

Response: <cr,lf>OK<cr,lf>

4. AT+BTM {Delete Incoming Peer Address}

This command is used to delete the peer address previously stored using AT+BTM<bd_addr>.

If the BTM device was connectable for the selected device before this command, it will be connectable for any device immediately after this command.

Response: <cr,lf>OK<cr,lf>

5. AT+BTM? {Read Incoming Peer Address}

This command is used to display the peer address stored in non-volatile memory, used to put the module in pure cable replacement mode.

Response: <cr,lf>12346789012

<cr,lf>OK<cr,lf>

If the location is empty, the response is as follows.

Response: <cr,lf>00000000000

<cr,lf>OK<cr,lf>

6. AT+BTR<bd_addr> {Set Outgoing Peer Address}

This command is used to store a peer address for outbound connections in non-volatile memory.

This command is used to set up a module in pure cable replacement mode. If S register 512 = 1 and the peer address is NOT 000000000000, then it will periodically (time specied via S register 505) attempt to connect to the peer address specied. In this circumstance all data from the host are

buffered in the receive buffer, until a Bluetooth connection is established with the peer device and it then sends the buffer across. This means that if the peer device is not in the vicinity and will never be there and S507=1 or 2, the device effectively becomes useless, as in this circumstance the module is not listening for commands arriving on the UART.

In this circumstance, a recovery is possible by one of two methods. The rst method assumes that the DTR from the host is connected to the DSR line of the module and S507=1. The second method assumes that this connection is absent and S507=1 or 2.

In the rst method it is enough to deassert the DTR line from the host and that will abort the autoconnect cycle. No “OK” is sent in response. Hence it is up to the host to send a character regularly (e.g., one per second) until the BTM device echoes all buffered characters to the host (provided echo is enabled). Once the BTM device echoes characters, it is in command mode.

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The second method is initiated by resetting the device and then ensuring that the text string

“AT+BT&BISM&<cr>” is sent (where <cr> is the carriage return character). There is special code which looks out for this magic command and terminates the autoconnect cycle if it sees it and conrms to the host of that fact by sending an “OK” response.

Response: <cr,lf>OK<cr,lf>

7. AT+BTR {Delete Outgoing Peer Address}

This command is used to delete the peer address previously stored using AT+BTR<bd_addr>.

Response: <cr,lf>OK<cr,lf>

8 AT+BTR? {Read Outgoing Peer Address}

This command is used to display the peer address stored in non-volatile memory, used to put the device in pure cable replacement mode.

Response: <cr,lf>12346789012

<cr,lf>OK<cr,lf> If the location is empty the response is as follows.

Response: <cr,lf>00000000000

<cr,lf>OK<cr,lf>

Bluetooth Proles

This section covers S-Registers and AT-Commands that are related to supported Bluetooth Proles on BTM.

 1. ProleActivation

In order to activate available proles and advertise them to potential client devices, S-Register 102 is used. Per default, only SPP is activated (value=1). Other supported proles can be activated by setting

the appropriate Flag in S-Register 102. Once S-Register 102 has been written, the changed value needs

to be saved to non-volatile memory (“AT&W”) and subsequently a reset (“ATZ”) or power cycle is required. Please note that “AT&W” saves the content of all S Registers to non-volatile memory.

 2. SPP(SerialPortProle)

The serial port prole (SPP) is used for serial data transmission with a remote device in both directions. It behaves like a wireless replacement for a serial cable.

SSP belongs to the group of serial stream oriented proles (SSO) so please refer to page 24 too.

In order to use SPP, the prole must be enabled in S102 (value=1). If it was not enabled earlier, set the S register accordingly and issue AT&W followed by ATZ.

2.1 SPP Example

This section gives an example on how an SPP connection between two Laird Technologies BTM devices can be established. It is assumed that two devices A and B are connected to a terminal program, e.g., Ezurio Terminal on a PC. The example sequence of AT commands is listed in Table 3.9. Figure 3.2 through to Figure 3.5 are presenting appropriate screenshots with Ezurio Terminal.

Phase Dev. AT Command Comment

Preparation A AT&F* Restore factory default settings

ATS102=1 Enable Serial Port Prole (SPP)

AT&W Store settings

ATZ Reset

Preparation B AT&F* Restore factory default settings

ATS102=1 Enable Serial Port Prole (SPP)

ATS0=1 Automatic response after one “RING”

AT&W Store settings

ATZ Reset

AT+BTP Make device temporary connectable and discoverable

ATI4 Query Bluetooth device address of local device <BdAddr_DevB>

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Phase Dev. AT Command Comment

Initiate connection

Connected A,B <data> Any character entered on one end is displayed at the

Enter command mode

Disconnect AT+SPH Response “NO CARRIER…” (A and B): disconnection

A AT+SPD<BdAddr_DevB> Initiate SPP connection from device A to device B.

Asynchronous messages:

“PAIR 0…” (pairing successful, A and B)

“RING…” (B only)

“CONNECT…” (connected, A and B)

other end.

A or B^^^ Response “OK” :

Command mode conrmed, now AT commands are expected at the UART; UART data from host is not sent

across to remote device.

conrmed.

Table 3.9: SPP Example Command Sequence

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Figure 3.2: SPP example - Preparation of Device A

Figure 3.3 SPP example – Preparation of Device B

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Figure 3.4: SPP example Device A - initiate connection, receiving data, command mode, disconnect

Figure 3.5: SPP example Device B - incoming connection, receiving data, disconnection

2.2 ATA {Accept Incoming SPP Connection Request}

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 123456789012,1101,<<cr,lf>

2.3 AT+SPD<bd_addr> {Make Outgoing SPP Connection}

Initiate an SPP connection to device with Bluetooth address <bd_addr> and SPP prole. The timeout is specied by S register 505.

For backward compatibility, the following command fulls the same purpose: ATD<bd_addr>.

Response: <cr,lf>CONNECT 123456789012,1101,><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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2.4 AT+SPDL {Remake Connection}

Make a SPP connection with the same device as that specied in the most recent AT+SPD command. An error will be returned if the ‘L’ modier is specied AND a Bluetooth address.

For backward compatibility, the following command fulls the same purpose: ATDL

Response: <cr,lf>CONNECT 123456789012,><cr,lf>

Or <cr,lf>NO CARRIER<cr,lf>

  2.5 AT+SPDR {MakeSPPConnectiontoPeerSpeciedinAT+BTR}

Make a SPP connection with the device address specied in the most recent AT+BTR command. An error will be returned if the ‘R’ modier is specied AND a Bluetooth address.

For backward compatibility, the following command fulls the same purpose: ATDR

Response: <cr,lf>CONNECT 123456789012,><cr,lf>

Or <cr,lf>NO CARRIER<cr,lf>

2.6 AT+SPH {Drop SPP Connection}

Drop an existing SPP connection or reject an incoming connection indicated by unsolicited RING messages.

For backward compatibility, the following command fulls the same purpose: ATH

Response: <cr,lf>NO CARRIER<cr,lf>

2.7 SPP – Incoming Connections

The Laird Technologies BTM device can be congured using the AT+BTP or AT+BTG command so that it will scan for incoming connections from other Bluetooth devices. It can also be

congured via S Register 512 to be in this mode by default on power up.

When the lower layers detect an SPP connection request, a RING 123456789012 string is sent to the host every second. The command ATA is used to accept the connection and ATH to reject the request.

On connection, if the S0 Register is >=0 then conrmation to the host is in the form:

CONNECT 123456789012,1101,<

When S0 register is -1, neither RING nor CONNECT is sent to the host and the connection is silently accepted.

If the S 100 register is non-zero, then after the ring indications specied by this register have been sent to the host, and the host has failed to accept or reject the incoming connection, then an automatic ‘hangup’ is initiated.

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2.8 SPP – Asynchronous Messages

RING

This string is sent to the host when a remote device is initiating a serial port connection. The fully qualied string is in the form RING 012345678901 where 012345678901 is a 12 digit hexadecimal number which corresponds to the remote device’s Bluetooth address. This response is sent to the host every two seconds until the host either accepts the connection using the ATA command or rejects it using the ATH command.

CONNECT 123456789012,1101,<

An SPP connection has with Bluetooth device 123456789012 has been established successfully.

The connection was initiated by the remote device (incoming).

CONNECT 123456789012,1101,>

An SPP connection has with Bluetooth device 123456789012 has been established successfully.

The connection was initiated by the local device (outgoing).

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2.9 SPP – S Registers

S Registers for SPP are summarized in Table 3.10.

S0 0 -1..15 Number of RING indication before automatically

answering an incoming 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.

S100 15 0..15 Number of RING indications before an auto

disconnection is initiated. A value 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.

Table 3.10: S Registers for SPP

 3. A2DP(AdvancedAudioDistributionProle)

The “Advanced Audio Distribution Prole” is used for unidirectional transmission of high quality audio streams between two Bluetooth devices. A2DP must be enabled by setting S 102 to a value of 128. Also, an A2DP role must be assigned to a BTM module, either source or sink. After this has been done,

the settings need to be stored by AT&W followed by ATZ.

An incoming A2DP connection request is accepted automatically if a valid link key for the paging device exists. If no link key is available, Secure Simple Pairing (SSP, BT2.1) or legacy pairing (BT2.0 or earlier) is carried out, depending on the Bluetooth version of the paging device.

After an A2DP connection has been established, the module remains in AT Command mode. S Register 531 is ignored for A2DP connections.

Version 1.2 of A2DP is supported.

The A2DP service record contains an optional eld which indicates the A2DP supported features of a device. This feature eld can be set by S312 for a sink and by S313 for a source. Please refer to

Table 3.16 for details.

Table 3.17 gives an overview on supported A2DP features on a BTM device.

Table 3.12 lists supported A2DP codec types.

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A2DP Feature Support in SRC (Audio Source) Support in SNK (Audio Sink)

Spec. BTM5xx Spec. BTM5xx

1. Audio Streaming M Yes M Yes

M: mandatory

Table 3.11: A2DP Supported Features on BTM5xx

A2DP Codec Type Support in SRC (Audio Source) Support in SNK (Audio Sink)

Spec. BTM5xx Spec. BTM5xx

1. SBC M Yes M Yes

2. MPEG-1,2 Audio O No O No

3. MPEG-2,4 AAC O No O No

4. ATRAC family O No O No

M: mandatory O: optional

Table 3.12: A2DP Supported Codec Types on BTM5xx

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3.1 A2DP Example 1

This section gives an example of an A2DP connection between a Laird Technologies BTM device as Audio Sink (wireless speaker/ wireless headphones) and a PC with a built in Bluetooth device and Toshiba Bluetooth Stack 2.1 as Audio Source.

The PC must support A2DP. If it is a different stack the procedure should be similar and follow

the steps of:

1.) Device discovery

2.) Device Selection

3.) Pairing

4.) Connection establishment (e.g., initiated by PC)

If you have a Bluetooth 2.0 or earlier stack on your PC, legacy pairing with PIN will occur. In that

case use AT+BTK=”<PIN>” to enter the PIN on the BTM device.

The BTM5xx device is assumed to be connected to a terminal program e.g. Ezurio Terminal on a PC. The sequence of AT commands and the instructions for the PC side are listed in Table 3.13. Figure 3.6 through to Figure 3.11 show appropriate screenshots.

Phase Dev. AT Command Comment

Preparation BTM5xx AT&F* Restore factory default settings

A2DP prole is enabled per default in S102

Audio Sink role is enabled per default in S300

ATS515=$040400 Set A2DP device class

ATS512=4 Make device connectable and discoverable (permanent setting)

AT&W Store settings

ATZ Reset

Preparation / Connection setup

Connected BTM5xx n/a Music can be heard on the speakers/headphones

Adjust Volume

Disconnect AT+APH Response “NO CARRIER 110D”: disconnection conrmed

PC n/a 1.) Open “Bluetooth Settings” from the taskbar icon - Figure 3.6

2.) Click on “New Connection” - Figure 3.6

3.) Click Next (Discover BT Devices) - Figure 3.7

4.) Select “Laird BTMM…” if not listed: click “Refresh” - Figure 3.8

5.) Click “Yes” on “Allow this Device to connect?” - Figure 3.9

6.) Connection is initiated by PC - Figure 3.10

7.) Open a player (e.g., Windows Media Player) to play some

music

8.) Connect a Headphone/Speaker to the Audio Output of the

BTM device

Troubleshooting:

If nothing can be heard, verify that a Bluetooth Audio Device has appeared in the Device Manager - Figure 3.1. Also check that the Bluetooth Audio Device is selected as speaker in your player application. Sometimes a player needs to be closed and restarted in order to send its audio output to a new speaker

device (which is the Bluetooth Audio Device here).

AT+GOU Increment volume (audio output gain) by one

AT+GOD Decrement volume (audio output gain) by one

Table 3.13: A2DP Example 1 Command Sequence

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Figure 3.6: A2DP example 1 – PC Bluetooth settings

Figure 3.7: A2DP example 1 – Start discovery of Bluetooth devices

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Figure 3.8: A2DP example 1 – Select Bluetooth device (Click “Refresh” if Laird BTMM is not listed)

Figure 3.9: A2DP example 1 – Conrm pairing (here: Secure Simple Pairing, no PIN required)

Figure 3.10: A2DP example 1: Connection established

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Figure 3.11: A2DP example 1: New Bluetooth Audio Device in the Device Manager

3.2 A2DP Example 2

This section gives an example of an A2DP connection between a Laird Technologies BTM5xx device

(A) as Audio Sink (wireless speaker/ wireless headphones) and another Laird Technologies BTM5xx device (B) as Audio source.

Both BTM5xx devices are assumed to be connected via UART to a terminal program, e.g., Ezurio Terminal on a PC. The required instructions along with the sequence of AT commands are listed in Table 3.14. Figure 3.12 to Figure 3.15 show appropriate screenshots.

Phase Dev. AT Command Comment

Preparation ext.

audio equipm.

Preparation A AT&F* Restore factory default settings

ATS515=$040400 Set A2DP device class (Sink)

ATS512=4 Make device connectable and discoverable (permanent setting)

AT&W Store settings

ATZ Reset

ATI4 Query Bluetooth device address of Dev. A <BdAddr_DevA>

1.) Connect an audio source (e.g., MP3 player) to the stereo audio input (line in) of Device B.

2.) Connect a headphone or a speaker to the stereo audio output (line out) of device A

A2DP prole is enabled per default in S102

Audio Sink role is enabled per default in S300

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Phase Dev. AT Command Comment

Preparation B AT&F* Restore factory default settings

A2DP prole is enabled per default in S102

ATS300=2 Enable Audio Source role

ATS515=$080400 Set A2DP device class (source)

AT&W Store settings

ATZ Reset

Initiate Connection

Connected Play music from the audio source

Adjust Volume

Disconnect A/B AT+APH Response “NO CARRIER 110D”: disconnection conrmed

B AT+APD<BdAddr_

DevA>

A AT+GOU Increment volume (audio output gain) by one

AT+GOD Decrement volume (audio output gain) by one

B AT+GIU Increment volume (audio input gain) by one

AT+GID Decrement volume (audio input gain) by one

Table 3.14: A2DP Example 2 Command Sequence and Instructions

Response:

“PAIR 0…” (pairing successful, A and B)

“CONNECT…” (connected, A and B)

Music should be audible on the headphones/speakers. If not: check audio output of the audio source (e.g., connect headphones directly to audio source for a test)

Note: the audio input gain (A2DP source) is a critical setting because the optimal setting cannot be veried by objective

means by the module itself.

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Figure 3.12: A2DP Example 2 – Preparation of Device A (Sink)

Figure 3.13: A2DP Example 2 – Preparation of Device B (Source)

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Figure 3.14: A2DP Example 2 –Initiate and Release Connection from Device B (Source)

Figure 3.15: A2DP Example 2 – Accepting Connection and Volume Adjustment Device A (Sink)

3.3 Enable A2DP

The advanced audio distribution prole (A2DP) is enabled by issuing ATS102=128. After verifying that a role has been set (S300 != 0) the S registers must be saved by AT&W. Finally issue ATZ to make the new settings effective. If the A2DP ag in S102 (0x80) is not set after ATZ although it was set and saved before ATZ, then S300 was = 0 at boot time, which is invalid for A2DP.

3.4 Select A2DP Role

The A2DP role is selected by S register 300 as follows:

0 – no role selected

1 – A2DP Sink (default)

2 – A2DP Source

The setting must be saved by AT&W and becomes effective on next power cycle (ATZ).

CAUTION: If S 300=0 at boot time (no role selected) and the A2DP ag (0x80) is set in S102, the A2DP ag will be cleared automatically because A2DP cannot be enabled without a role selected.

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AT COMMAND SET REFERENCE

4. Set A2DP Device Class

ATS515=$<device_class

>; AT&W; ATZ

hex

For compliance with the A2DP specication, [2] (and hence for successful interoperability to other devices) it is required to set up a valid device class code. The default device class code of a BTM device is 0x001F00 which is invalid for the A2DP prole.

The A2DP specication [2] mandates the following requirements for the device class of an A2DP device:

1. Mandatory to set the ‘Rendering’ bit for the SNK and the ‘Capturing’ bit for the SRC in the Service

Class eld.

2. Recommended to set ‘Audio/Video’ as Major Device class both for the SNK and the SRC.

3. Select the appropriate Minor Device class as dened in the Bluetooth Assigned Numbers [8].

There is a tool available on the internet for creating a particular device class code: refer to [9].

With the assumptions above (Major Device class = Audio/Video), Table 8 in [8] gives the complete list

of codes for the minor device class. If you are not sure about the minor device class, use the row

marked with n/a for the minor device (e.g., 0x040400 for sink or 0x080400 for source).

Table 3.15 gives some examples of device class codes for A2DP devices.

Device Class Code Major Service Major Device Minor Device A2DP Role

0x040400 Rendering Audio/Video n/a Sink

0x040414 Rendering Audio/Video Loudspeaker Sink

0x040418 Rendering Audio/Video Headphones Sink

0x04041C Rendering Audio/Video Portable Audio Sink

0x040420 Rendering Audio/Video Car audio Sink

0x080400 Capturing Audio/Video n/a Source

0x080410 Capturing Audio/Video Microphone Source

0x080428 Capturing Audio/Video HiFi Audio Device Source

Table 3.15: A2DP device class code – examples

The device class is written to the module using ATS515=$<device_class is the 6 character device class code without leading “0x”. Use subsequent AT&W and ATZ for the new

> where <device_class

hex

value to become effective. Please also refer to page 13, number 4.

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4.1 Initiate A2DP Connection

AT+APD<bd_addr

Initiate A2DP connection to Bluetooth address <bd_addr complementary role to the local device. If link keys are missing in one or both devices, pairing will either occur automatically or pairing is required to be initiated by AT+BTW<bd_addr This depends on various factors like the combination of local and remote IO capabilities or the

hex

>. The remote device must support the

hex

Bluetooth version of the remote device.

Response:

<cr><lf>OK<cr><lf> (immediately)

<cr><lf>PAIR 0 <bd_addr> 00<cr><lf> (rst time only, auto pairing without MITM authent.)

<cr><lf>CONNECT <bd_addr>,110D,><cr><lf>

Or:

<cr><lf>OK<cr><lf> (immediately)

<cr><lf>NO CARRIER 110D<cr><lf> (not successful)

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AT COMMAND SET REFERENCE

4.2 Output Gain Settings – A2DP Sink

AT+GOU / AT+GOD

AT+GOU – Increment audio output gain (volume).

AT+GOD – Decrement audio output gain (volume).

Response:

<cr><lf>ERROR 57<cr><lf> – Maximum gain level reached

<cr><lf>ERROR 58<cr><lf> – Minimum gain level reached

The output gain level can be set directly using S register 589. Alternatively, S register 689 can be used to set the required overall output gain in dBr multiplied by 10. Please refer to section 1, page 74.

4.3 Input Gain Settings – A2DP Source

AT+GIU / AT+GID

AT+GIU – Increment audio input gain.

AT+GID – Decrement audio input gain.

Response:

<cr><lf>ERROR 57<cr><lf> – Maximum gain level reached

<cr><lf>ERROR 58<cr><lf> – Minimum gain level reached

The input gain level can be set directly using S register 590. Alternatively, S register 690 can be used to set the required overall input gain in dBr multiplied by 10. Please refer to section 1, page 74.

4.4 Release A2DP Connection

AT+APH / ATH110D

Release an A2DP connection by AT+APH. Alternatively, ATH110D can be used. (110D presents the UUID for the A2DP prole). Please refer to section4, page 83.

4.5 Supported Features – A2DP Sink

S312

Use S Register 312 to set the A2DP sink supported features that will be advertised in the A2DP

service record. Refer to Table 3.16. The S register needs to be saved (AT&W) and the module needs to be power cycled (ATZ) for a new value to become effective.

4.6 Supported Features – A2DP Source

S313

Use S Register 313 to set the A2DP source supported features that will be advertised in the A2DP

service record. Refer to Table 3.16. The S register needs to be saved (AT&W) and the module needs to be power cycled (ATZ) for a new value to become effective.

Task AT-Command / SRegister Comment

Enable A2DP prole S102 128 = A2DP, Error 46 if A2DP role has not been

set (see S300)

Needs subsequent AT&W and ATZ to

become effective

Set A2DP role S300 [0..2] 0 = feature not set

1 = A2DP Sink (default)

2 = A2DP Source

Needs subsequent AT&W and ATZ to

become effective

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AT COMMAND SET REFERENCE

Task AT-Command / SRegister Comment

Initiate outgoing A2DP connection

Close only A2DP connection “AT+APH” or

Close all connections ATH* Response:

Set gain level S589 [0..22], default = 15Set codec output gain level (applies to sink)

Set overall gain (dBr * 10) S689 [-450..215] Set codec output gain in dBr * 10

Increment Gain AT+GOU Increment codec output gain by 1 step in gain

Decrement Gain AT+GOD Decrement codec output gain by 1 step in gain

Set A2DP Sink supported features bit mask

Set A2DP Source supported features bit mask

AT+APD<bd_addr> Response if accepted:

“CONNECT 0123456789012,110D,>”

Response if rejected:

“NO CARRIER 110D”

Response:

“ATH110D”

S590 [0..22], default = 15Set codec input gain level (applies to source)

S690 [-450..215] Set codec input gain in dBr * 10

AT+GIU Increment codec input gain by 1 step in gain table

AT+GID Decrement codec input gain by 1 step in gain table

S312 [1..15] Bitmask - sink supported features:

S313 [1..15] Bitmask - source supported features:

Table 3.16: A2DP – S Registers and AT-Commands

“NO CARRIER 110D” if connection has existed and S329=0

“NO CARRIER” if connection has not existed and S329=0

“NO CARRIER <proleUUID>” for each prole that was previously connected (see section 4, page 83)

(applies to sink), default = 0

(applies to source), default = 0

table (refer to section 1, page 74)

(refer to section 1, page 74)

table (refer to section 1, page 74)

(refer to section 1, page 74)

Bit 0 = Headphone (default)

Bit 1 = Speaker

Bit 2 = Recorder

Bit 3 = Amplier

Subsequent AT&W plus ATZ required for a new

value to become effective

Bit 0 = Player (default)

Bit 1 = Microphone

Bit 2 = Tuner

Bit 3 = Mixer

Subsequent AT&W plus ATZ required for a new

value to become effective

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AT COMMAND SET REFERENCE

 5 AVRCP(AudioVideoRemoteControlProle)

The “Audio/Video Remote Control Prole” is used to remotely control audio or video streaming devices. A device must be dened as either control (CT) or target (TG). Furthermore, one of four categories (Player/Recorder, Monitor/Amplier, Tuner, Menu) must be assigned to a device.

Version 1.0 of AVRCVP is supported.

The AVRCP specication [3] adopts the AV/C Digital Interface Command Set (AV/C command set, dened by the 1394 Trade Association) device model and control message format. In this device model a remote control target consists of one or more subunits. At least the subunit ”PANEL” must exist. Remote control commands are passed to a subunit with the “PASS THROUGH” command. A BTM device, congured as target will support one PANEL-subunit.

Table 3.17 gives an overview on supported AVRCP features on a BTM device.

AVRCP Feature Support in CT (Control) Support in TG (Target)

Spec. BTM5xx Spec. BTM5xx

1. Connection establishment for control M Yes O Yes

2. Release connection for control M Yes M Yes

3. Sending UNIT INFO command O Yes X No

4. Receiving UNIT INFO command X No M Yes

5. Sending SUBUNIT INFO command O (1) X No

6. Receiving SUBUNIT INFO command X No M Yes

7. Sending VENDOR DEPENDENT command O No X No

8. Receiving VENDOR DEPENDENT command X No O No

9. Sending PASS THROUGH command M Yes X No

10. Receiving PASS THROUGH command X No M Yes

M: mandatory O: optional X: excluded

(1) incomplete

Table 3.17: AVRCP Supported Features on BTM5xx

5.1 AVRCP Example 1

This section gives an example of an AVRCP connection between a Laird Technologies BTM5xx device as AVRCP Controller and a PC with a built in Bluetooth device and Toshiba Bluetooth Stack

2.1 as AVRCP Target.

For any other Bluetooth Stack with AVRCP (target role) support, the setup should follow the steps of:

1. Identifying Bluetooth Device Address of PC

2. Enabling AV Remote Control Service

3. Selecting player and/or setup display of incoming remote control commands

The BTM5xx device is assumed to be connected to a terminal program, e.g., Ezurio Terminal on a PC. The sequence of AT commands and the instructions for the PC side are listed in Table 3.18. Figure 3.16 to Figure 3.21 show appropriate screenshots.

This example can be combined with the A2DP Example 1 (Section3.1, page 34). Then the AVRCP connection should be initiated after A2DP is connected.

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AT COMMAND SET REFERENCE

Phase Dev. AT Command Comment

Preparation BTM5xx AT&F* Restore factory default settings

AVRCP prole is enabled per default in S102 AVRCP Control role is enabled per default in S301

ATZ Reset

Preparation PC n/a 1.) Select “Options…” from the Bluetooth icon in the

taskbar (Figure 3.16)

2.) Identify the PC’s Bluetooth Address <BdAddr_PC> in the “General” tab of Bluetooth Options (Figure 3.16)

3.) Make sure that “AV Remote Control Service is enabled” (Figure 3.16)

4.) Go to “Other” tab of Bluetooth Options and Click Button “AV Player…” (Figure 3.17)

5.) Select “TopRight” at the “Display Position” dropdown menu (Figure 3.17)

6.) Close each window by clicking “OK”

Initiate Connection

Connected, send remote control commands

Disconnect BTM5xx AT+AVH Response: (Figure 3.20)

BTM5xx AT+AVD<BdAddr_PC> Response: (Figure 3.19)

“CONNECT <BdAddr_PC>,110E,>” (AVRCP connected)

BTM5xx AT+AVC44 Send “Play” (Figure 3.20, Figure 3.21)

Response: “OK” - command accepted “AVPTC 0,44,0” -conrmation received from PC “AVPTC 0,44,1” -conrmation received from PC

Reception of command should be displayed in top-right

corner of PC screen (Figure 3.21), Player should start

playing.

AT+AVC46 Send “Pause” (Figure 3.20, Figure 3.21)

Response: “OK” - command accepted “AVPTC 0,46,0” -conrmation received from PC “AVPTC 0,46,1” -conrmation received from PC

Reception of command should be displayed in top-right

corner of PC screen (Figure 3.21), Player should pause.

AT+AVC45 Send “Stop” (Figure 3.21)

Response: “OK” - command accepted “AVPTC 0,45,0” -conrmation received from PC “AVPTC 0,45,1” -conrmation received from PC

“NO CARRIER 110E” (disconnection conrmed)

Table 3.18: AVRCP Example 1 Command Sequence

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AT COMMAND SET REFERENCE

Figure 3.16: AVRCP Example 1 – Bluetooth Address of PC and AV Remote Control Service

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Figure 3.17: AVRCP Example 1 – Player Selection and Receiving Commands Display Setup

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AT COMMAND SET REFERENCE

Figure 3.18: AVRCP Example 1 – Secure simple pairing dialogue

Figure 3.19: AVRCP Example 1 – BTM5xx Preparation and Connection Setup

Figure 3.20: AVRCP Example 1 – BTM5xx Sending Commands and Connection Release

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Figure 3.21: AVRCP Example 1 – Incoming AVRCP commands (top-right corner of screen)

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AT COMMAND SET REFERENCE

5.2 AVRCP - Control (CT) and Target (TG)

This section describes AT Commands an S registers which are common to BTM5xx AVRCP Controller role and AVRCP Target role.

5.2.1 Initiate AVRCP Connection

AT+AVD<bd_addr

Initiate AVRCP control connection to Bluetooth address <bd_addr be congured as AVRCP Control by S register 301 = 1. Furthermore, a category must be

hex

>. The module must

hex

selected in S register 302.

Response: <cr,lf>CONNECT 123456789012,110E,><cr,lf>

Or: <cr,lf>NO CARRIER 110E<cr,lf>

Or: <cr,lf>ERROR 47<cr,lf>

Or: <cr,lf>ERROR 48<cr,lf>

After an AVRCP connection has been established, the module remains in AT command mode. S Register 531 is ignored for AVRCP connections.

5.2.2 Release AVRCP Control Connection

AT+AVH

Release AVRCP control connection.

Response <cr,lf >NO CARRIER 110E<cr,lf>

5.3 AVRCP - Control (CT)

This section describes AT Commands an S registers when BTM5xx is congured as an AVRCP Controller (S301=1).

5.3.1 Send UNIT INFO Request

AT+AVU

Send a Unit Info request to a connected AVRCP target.

Response immediately: <cr,lf>OK<cr,lf>

On command completion:

<cr,lf>AVUR <n>,<unit_id

<n> = status

: 0 – success

dec

>,<unit_type

hex

>,<company_id

hex

><cr,lf>

hex

1 – fail

4 – timeout

For unit_type see Table 3.21: AV/C Unit/Subunit Types.

5.3.2 Send SUBUNIT INFO Request (Incomplete*)

AT+AVS<page

dec

Send a Subunit Info request to a connected AVRCP target.

Response: <cr,lf>OK<cr,lf> (immediately)

And: <cr,lf>AVSR <n>,<page

<n> = status

: 0 – success

dec

>,<pagedata

dec

> <cr,lf> (after command completion)

hex

1 – fail

4 – timeout

<page

<pagedata

> : requested page [0..31]

dec

>: 1st word of requested page

hex

*) incomplete because only the rst word of the requested page is being displayed in the AVSR asynchronous message

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AT COMMAND SET REFERENCE

5.3.3 Send Remote Control Command

AT+AVC<operation_id

Send a remote control command to a connected AVRCP target. Internally, a PASS THROUGH command is created and sent to the PANEL subunit of the AVRCP target.

<operation_id

specied in Table 3.20. Some Operation IDs can be replaced by mnemonics, see Table 3.20.

<button_state> represents “Button pushed” (=0) or “Button released” (=1) If <button_state> is not specied, two PASS THROUGH commands, each with button_state=0 and button_state=1, will be created and being sent consecutively.

The “OK” response is sent immediately on receipt of AT+AVC command. On command completion, an unsolicited message will be sent to the host in the form “AVPTC <n>, <bd_addr>, <button_state>”. AVPTC means “AVrcp Pass Through Conrmation”. Parameter n indicates the command’s status:

‘n’=0: successful, command conrmation received from target

‘n’=1: timeout, target has not sent conrmation within the specied maximum time

‘n’=2: all other unsuccessful outcomes

Parameters:

<operation_id

<button_state> (optional) : ‘0’ - Button pushed

‘1’ - Button released

Response: <cr,lf>OK<cr,lf> (immediately)

And: <cr,lf>AVPTC <n>,<operation_id

(after command completion)

If status n indicates an unsuccessful outcome,<operation_id

5.4 AVRCP – Target (TG)

This section describes AT Commands an S registers when BTM5xx is congured as an AVRCP Target (S301=2). In this mode, BTM5xx supports one subunit PANEL (see [3]).

> is the value for the actual remote control command. Valid values are

hex

> (mandatory): see Table 3.20

hex

>,<button_state>

hex

>,<button_state><cr,lf>

hex

> and <button_state> are omitted.

hex

5.4.1 Incoming AVRCP Connection Request

An incoming AVRCP connection request is accepted automatically if a valid link key for the

paging device exists. If no link key is available, Secure Simple Pairing (SSP, BT2.1) or legacy pairing (BT2.0 or earlier) is carried out, depending on the Bluetooth Version of the paging device.

After an AVRCP connection has been established, the module remains in AT command mode. S Register 531 is ignored for AVRCP connections.

5.4.2 UNIT INFO Response

It is mandatory to respond to a UNIT INFO command if congured as AVRCP target. Required response parameters are IEEE Company ID and a Unit Type.

The IEEE Company ID is a 24 bit integer which can be set via S Register 303.

The response is sent automatically with the company ID as per S303 and a xed unit type of 0x09 (“Panel”).

5.4.3 SUBUNIT INFO Response

It is mandatory to respond to a SUBUNIT INFO command if congured as AVRCP target. Required response parameters are Subunit type and MaxSubUnitId.

The response is sent automatically with a xed value of 0x09 (“Panel”) for parameter Subunit type and a xed value of 0x00 for parameter MaxSubUnitId (only one subunit exists, which is panel).

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AT COMMAND SET REFERENCE

5.4.4 PASS THROUGH Indication

An incoming PASS THROUGH command will be indicated by an unsolicited message.

AVPTI <subunit_id

For subunit_id

>,<operation_id

hex

see Table 3.21. For operation_id

hex

>,<button_state>

hex

see Table 3.20.

hex

<button_state>: ‘0’ is Button pushed

‘1’ is Button released

5.4.5 PASS THROUGH Response

AT+AVR<avrc_response_type

hex

If S register 310 == 0, a Pass Through (PT) response is required from the host. The response is sent using the command:

AT+AVR<avrc_response_type

dec

Parameter:

<avrc_response_type

>: see Table 3.22, write-value.

dec

If S register 310 == 1, a Pass Through response is sent automatically with an <avrc_response_type> dened by S register 311. In this case, the host is not required to respond.

Task AT-Command / S Register Comment

Enable AVRCP prole S102 256 = AVRCP, Error 47 if AVRCP role has not

been set (see S301);

Error 48 if S301== 2 and Category has not been set (see S302)

Needs subsequent AT&W and ATZ to be-

come effective

Set AVRCP role S301 [0..2] 0 = disabled

1 = Control “CT” (default) 2 = Target “TG” Needs subsequent AT&W and ATZ to be-

come effective

Set AVRCP category S302 [0..4] 0 = Feature disabled (default)

1 = Player/Recorder 2 = Monitor/Amplier 3 = Tuner 4 = Menu Needs subsequent AT&W and ATZ to be-

come effective

Initiate outgoing AVRCP control connection

AT+AVD<bd_addr> Response if accepted:

“CONNECT 0123456789012,110E,>”

Response if rejected: “NO CARRIER 110E”

Close only AVRCP connection “AT+AVH“ or “ATH110E” Response:

“NO CARRIER 110E” if connection has existed and S329=0 “NO CARRIER” if connection has not existed and S329=0

Close all connections ATH* Response:

“NO CARRIER <proleUUID>” for each prole that was previously connected (see section 4, page 83)

Send remote control command

(Control)

AT+AVC<operation_

>,<state>

hex

<operation_id <state> (optional): ‘0’ Button pushed ‘1’ Button released

>: see Table 3.20

hex

Response on command completion: “AVPTC <n>,<operation_id

>,<state>”

hex

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AT COMMAND SET REFERENCE

Task AT-Command / S Register Comment

Send a Unit Info request

(Control)

Send a Subunit Info request

(Control)

AT+AVU Response on command completion: “AVUR

<n>,<unit_id id

>”

hex

Successful if <n> = 0

>,<unit_type

hex

>,<company_

hex

AT+AVS (incomplete*) Response on command completion:

“AVSR <n>,<page <cr,lf>”

>,<pagedata

dec

hex

Successful if <n> = 0 *) only rst word of the pagedata is being

displayed in the AVSR response message

Set Company Id (Target) S303 [0..0xFFFFFF] IEEE Company ID, 24bit hexadecimal,

Required for UNIT INFO Response in AVRCP target mode, default value is 0.

Set Unit Type (Target) S304 [0..0xFF] currently always 0x09, read only, reserved for

future usage

Enable Unit Info Response

(Target)

S305 [0..1] 0 – reject incoming Unit Info Requests

1 – accept incoming Unit Info Requests and send response automatically (default) with Company ID as per S303 and unit type = 0x09 (“Panel”, xed)

Enable Subunit Info Response

(Target)

S306 [0..1] 0 – reject incoming Subunit Info Requests

1 – accept incoming Subunit Info Requests and send response automatically (default) with Subunit type = 0x09 (“Panel”, xed) and MaxSubUnitId = 0x00 (xed)

Congure PASS THROUGH (PT) Response (Target)

S310 [0..1] 1 = Enable automatic PT-response, response

type is read from S311, (default) 0 = Host is required to respond to PT-Indica-

tion, see ‘AT+PTR’

Set automatic PT response type

(Target)

S311 [0.. 7] This value is queried for automatic PT-Re-

sponse, see Table 3.22

Default value is “accepted” 1w/ 9r

Respond to incoming Pass

Through command (Target)

AT+AVR<avrc_response_type

> <avrc_response_type

hex

If S 310 == 1, response from host is not

>: see Table 3.22

hex

required.

Table 3.19: AVRCP – S Registers and AT Commands

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AT COMMAND SET REFERENCE

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Command Operation ID

Select 0x00 Up 0x01 Down 0x02 Left 0x03 Right 0x04 Right up 0x05 Right down 0x06 Left up 0x07 Left down 0x08 Root menu 0x09 Setup menu 0x0A Contents menu 0x0B Favourite menu 0x0C Exit 0x0D 0 0x20 1 0x21 2 0x22 3 0x23 4 0x24 5 0x25 6 0x26 7 0x27 8 0x28 9 0x29 Dot 0x2A Enter 0x2B Clear 0x2C Channel up 0x30 Channel down 0x31 Sound select 0x32 Input select 0x33 Display information 0x34 Help 0x35 Page up 0x36 Page down 0x37 Power 0x40 Volume up 0x41 Volume down 0x42 Mute 0x43 Play 0x44 Stop 0x45 Pause 0x46 Record 0x47 Rewind 0x48 Fast forward 0x49 Eject 0x4A Forward 0x4B Backward 0x4C Angle 0x50 Sub picture 0x51 F1 0x71 F2 0x72 F3 0x73 F4 0x74 F5 0x75 Vendor unique 0x7e

Table 3.20: AVRCP – Operation IDs for Remote Control Commands

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AT COMMAND SET REFERENCE

Unit / Subunit Type Value

Monitor 0x00

Audio 0x01

Printer 0x02

Disc 0x03

Tape recorder player 0x04

Tuner 0x05

CA 0x06

Camera 0x07

Reserved 0x08

Panel 0x09

Bulletin board 0x0A

Camera storage 0x0B

Vendor unique 0x1C

Reserved for all 0x1D

Extended 0x1E

Unit 0x1F

Table 3.21: AV/C Unit/Subunit Types

AVRC Response Type Read-Value (S311,

sent in response)

Not implemented 8 0

Accepted 9 1

Rejected 10 2

In transition 11 3

Stable 12 4

Changed 13 5

Interim 15 6

Bad prole 16 7

Table 3.22: AVRC Response Types

Write-Value (S311) or

AT+AVR<parameter>

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Message Comment

CONNECT 123456789012,110E,> Outgoing AVRCP connection established

‘123456789012’ – bd_addr of peer device ‘110E’ – UUID indicating AVRCP

CONNECT 123456789012,110E,< Incoming AVRCP connection established

‘123456789012’ – bd_addr of peer device ‘110E’ – UUID indicating AVRCP

NO CARRIER 110E AVRCP connection rejected or closed

NO CARRIER All Connections closed

AVUR <n>,<unit_id>,<unit_type

> <company_id

hex

> Response to AT+AVU (UNIT INFO Request), indicates

hex

completion of command

<n> = status 1 – fail 4 – timeout

<unit_id

<unit_type>: see Table 3.21 <company_id>: IEEE Company ID

: 0 – success

dec

>: Unit ID

hex

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AT COMMAND SET REFERENCE

Message Comment

AVSR <n>,<page

>,<pagedata

dec

> Response to AT+AVS (SUBUNIT INFO Request), Indi-

hex

cates completion of command

<n> = status 1 – fail

: 0 – success

dec

4 – timeout

AVPTI <subunit_id

>,<operation_id

hex

<page <pagedata

>,<state> Indication of incoming Pass Through command

hex

<subunit_id <operation_id

<state>: ‘0’ – Button pushed

> : requested page [0..31]

dec

> : 1st word of requested page

hex

>: subunit id

hex

>: see Table 3.20

hex

‘1’ – Button released

AVPTC <n>,<operation_id

>,<state> Conrmation of AT+AVC (Control Command

hex

Request) <n>: ‘0’ – successful ‘1’ – timeout ‘2’ – not successful, other than timeout

Table 3.23: AVRCP Unsolicited Messages

5.5 AVRCP GPIO Mapping

GPIOs can be mapped to AVRCP Commands (operations) with GPIO Conguration Registers S 651 to 663. If Function mapping is enabled (FME=1), and if a valid av_operation_id (see Table 3.20) is assigned to a GPIO and if the module is congured as AVRCP Control (S 301), a rising edge

causes the appropriate command request to be sent to the connected AVRCP target as if AT+AVC

was issued with <state>=0 (Button pushed). A trailing edge on this GPIO will cause the same command to be sent with <state>=1 (Button released).

The logical level of a GPIO can be inverted by setting the appropriate ag “INV” in the appropriate GPIO conguration register.

If congured as AVRCP Target, the direction ag (DIR) in the GPIO Conguration Register must be

set to 1 in order to indicate received commands at a digital output. A write operation to a GPIO will not have any effect if that GPIO is mapped to AVRCP.

The level inversion Flag INV of the GPIO Conguration Register also applies in target mode.

Restrictions can apply if certain GPIOS will be reserved for other functions in future, e.g. coexistence supporting functionality.

Please refer to section Error! Reference source not found.

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 6. HSP(HeadsetProle)

The “Headset Prole” provides full-duplex audio capability combined with minimal device control commands. Audio bandwidth is limited and deemed to be sufcient for, e.g., voice links. Table 3.24 lists the feature requirements of the HSP specication [4] and the level of support by BTM5xx.

Version 1.2 of the Headset Prole specication is supported.

In most cases it will be preferred to use the more advanced Hands-Free Prole (HFP).

HSP denes the role of the headset (HS) and the role of the audio gateway (AG) which are both supported on BTM5xx. They are enabled by setting the appropriate ag in S-Register 102 (plus subsequent “AT&W” and “atz“).

An HSP connection can be in one of two states: ACL connected or audio connected. The ACL is initiated by either HS or AG. The audio connection (a SCO link) shall always be initiated and released by the AG.

A host processor is required, using AT commands to control the BTM5xx module (hosted operation mode).

An AT command beginning with AT+HS... indicates afliation to the Headset role of HSP.

An AT command beginning with AT+HSG…indicates afliation to the Audio Gateway role of HSP.

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HSP Feature Support in HS Support in AG

Specication BTM5xx Specication BTM5xx

1. Incoming audio connection M Yes M Yes

2. Outgoing audio connection M Yes O Yes

3. Audio connection transfer M Yes M Yes

4. Remote audio volume control O (1) O (1)

M: mandatory O: optional

(1) Supported planned for future rmware release

Table 3.24: Headset Prole supported features on BTM5xx

6.1 Headset role (HS)

Headset role is activated by setting ag 0x02 in S102 plus “AT&W” plus “ATZ“.

Figure 3.22 shows a block diagram of a headset and how a BTM5xx module would be integrated in hosted operation mode.

Host

1 Button

Controller

AT command interface

Speaker

Audio

BTM5xx [HS]

Microphone

Figure 3.22 Headset block diagram

6.1.1 Initiate ACL connection from HS

AT+HSD<bd_addr

Initiate ACL connection from local headset instance to remote device with <bd_addr

The remote device must support the audio gateway role (AG) of the headset prole (HSP).

Response: <cr,lf>CONNECT 123456789012,1112,><cr,lf>

Or: <cr,lf>NO CARRIER<cr,lf>

Or: <cr,lf>ERROR 59<cr,lf>

Or: <cr,lf>ERROR 63<cr,lf>

After an ACL connection has been established, the module remains in AT command mode. S Register 531 is ignored for HSP connections. An audio connection should be established

within short time. The command is “AT+HSB”.

6.1.2 Send “AT+CKPD=200”

AT+HSB

Send “AT+CKPD=200” to connected audio gateway. This indicates a user initiated action to the gateway, e.g., a button press. Depending on the current audio connection state, the audio gateway will establish or release the audio connection subsequently. Please refer to Table 3.25.

hex

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Connection status Outcome of AT+HSB (“AT+CKPD=200”)

ACL connected (ATI63=1) Audio link will be initiated by AG

Referred to as “Audio Connection Transfer from AG to HS” in HSPv1.2

Audio connected (ATI63=2) Audio link and ACL should be released by the AG, actual outcome depends

on AG

Table 3.25: Outcome of “AT+HSB”

6.1.3 Release Connection from Headset

AT+HSH

Release connection from local Headset instance. Audio connection will be released if existing, ACL will be released anyway.

A connection release, initiated by the Headset, is not dened in the Headset Prole specication [4]. A prole compliant disconnection is initiated from Headset by sending “AT+CKPD=200” (use “AT+HSB”) to the audio gateway.

This command was introduced for the sake of completeness and should be used for testing purposes only.

Response:

On audio disconnection (optional): <cr,lf>HS”AU0”<cr,lf>

On ACL disconnection: <cr,lf>NO CARRIER 1108<cr,lf>

6.1.4 Headset status

ATI63

Returns the status of the Headset (HSP) instance:

0 = not connected

1 = ACL connected

2 = Audio connected

6.1.5 Headset asynchronous messages

CONNECT <bd_addr

An ACL connection to headset has been established.

<bd_addr

<uuid

: “1112” if it was an outgoing connection.

<dir> : “<”/”>”/”I”/”O”’ optionally indicates the direction (incoming/outgoing),

please refer to S331 and section 6, page 85.

HS”RING”

HS has received a “RING” indication from the connected audio gateway. HS is expected to respond with “AT+CKPD=200” (see “AT+HSB”).

HS”AU1”

Audio connection (SCO) has been established (= “audio on”).

HS”AU0”

Audio connection (SCO) has been released (= “audio off”).

NO CARRIER 1108

ACL connection to local HS-instance has been released. Please note section 6, page 85.

> : Bluetooth address of headset device

hex

> : “1108” if it was an incoming connection

hex

>,<uuid

hex

>[,<dir>]

hex

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AT COMMAND SET REFERENCE

6.1.6 Headset summary

Task AT-Command / S Register Comment

Enable HSP-HS role S102 0x02 = HS role of HSP (bitmask), needs

subsequent “AT&W” and “atz” to

activate

Initiate ACL from headset AT+HSD<bd_addr

Send “Button pressed” (HS) AT+HSB Sends “AT+CPKD=200” to the con-

Disconnect from HS AT+HSH / ATH1108 / ATH* For test purposes only, because discon-

Enable “ATH” for HS S332 Enable HS disconnection “ATH1108”

Inquire HS status ATI63 0 = not connected

Table 3.26: Headset role (HSP) – Summary of S Registers and AT Commands

> Responses:

hex

successful: “CONNECT 123456789012,1112,>” failed: “NO CARRIER” prole disabled: “ERROR 59” incorrect state: “ERROR 63”

nected gateway

nection initiated by HS other than send-

ing “AT+CKPD=200” to gateway is not dened in HSP specication.

and “ATH*” 0 = disabled (default) 1 = enable

Should only be enabled for test purposes, because disconnection initiated by

HS other than sending “AT+CKPD=200” to gateway is not dened in HSP specication.

1 = ACL connected 2 = Audio connected

6.2 Audio gateway role (AG-HSP / HSG)

Audio gateway role (for HSP) is activated by setting ag 0x08 in S102 plus “AT&W” plus “atz“. Figure 3.23 outlines a block diagram of an audio gateway with a BTM5xx in hosted operation mode.

local speaker,

local microphone

BTM5xx

Audio Network

Audio routing

Mobile

[HSG] or

control

Termination

[HFG]

Host

AT Command

Interface

(set of buttons / keypad / display)

Controller

Telephone control

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Figure 3.23 Audio Gateway block diagram

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6.2.1 Initiate ACL Connection from AG (HSP)

AT+HSGD<bd_addr

Initiate ACL connection from local headset-gateway instance to remote device with <bd_addr

The remote device must support the headset role (HS) of the headset prole (HSP).

Response: <cr,lf>CONNECT 123456789012,1108,><cr,lf>

Or: <cr,lf>NO CARRIER<cr,lf>

Or: <cr,lf>ERROR 59<cr,lf>

Or: <cr,lf>ERROR 63<cr,lf>

After an ACL connection has been established, the module remains in AT command mode. S Register 531 is ignored for HSP connections.

If S-Register 345=1, the audio gateway will alert the headset immediately by sending “RING” or by performing the in-band ringing procedure (depending on S Register 346) and wait for the response “AT+CKPD=200”.

If S-Register 345=0, an incoming call must be signalized to the HS manually by issuing “AT+HSGC”. This will either send the “RING” message to the HS or perform the in-band ringing procedure and wait for “AT+CKPD=200” to be received from the HS.

In the case the headset does not respond, it is the host’s responsibility to terminate the

connection by “AT+HSGH”.

6.2.2 Alert HS by Sending “RING” Message or In-Band Ringing

AT+HSGC

When in “ACL connected” state, the command “AT+HSGC” alerts the HS either by sending “RING” (if S346=0) or by in-band ringing (if S346=1). In the latter the AG is assumed to

create an in-band ringtone which is audible on the HS through the SCO connection. The in-band ringtone is not created by BTM5xx itself. It is required to be created by the external circuit and to be connected to the BTM5xx analogue audio input.

In-band ringing is indicated by “ATI64” returning 6. Alerting using the “RING” message is indicated by “ATI64” returning 5.

In both cases the response “AT+CKDP=200” (“Button pressed”) is expected from the HS.

hex

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6.2.3 Cancel an Ongoing Alert Process

AT+HSGCH

When the HSG is alerting the HS (ATI64 = 5 / 6 ) this state can be cancelled by “AT+HSGCH”. If in-band ringing was active (ATI64 = 6) , the audio connection will be released.

6.2.4 Release Audio from HSG Side/Transfer Audio from HS to HSG

AT+HSGR

When in “audio connected” state, the AG can transfer the audio connection from the headset to itself with “AT+HSGR”. This results in the release of the audio connection whereas the ACL connection is retained. In “ACL connected” state, the headset (HS) is able to transfer the audio connection back to the HS by sending “AT+CKPD=200”.

6.2.5 Initiate Audio from HSG Side/Transfer Audio from HSG to HS

AT+HSGA

When in “ACL connected” state, the AG can transfer the audio connection from itself to the headset by “AT+HSGA”. This results in the establishment of a SCO based audio connection.

6.2.6 Connection Release from AG

AT+HSGH

Release existing connection to a HS. If the HS is alerted, alerting will be cancelled. If an

audio connection exists it will be released rst. ACL will be released in either case.

Response:

On audio disconnection (optional): <cr,lf>HSG”AU0”<cr,lf>

On SLC disconnection: <cr,lf>NO CARRIER 1112<cr,lf>

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6.2.7 Enable Automatic Alerting on SLC Establishment

S345

S-Register 345 enables automatic alerting on ACL establishment. It contains a bitmask where bit0 corresponds to outgoing ACL connections and bit1 corresponds to incoming ACL connections.

If automatic alerting is disabled (S345=0), it can be initiated manually by “AT+HSGC”.

6.2.8 Enable In-Band Ringing

S346

In-band ringing is enabled by S-Register 346 (value =1). If disabled (S346=0), the “RING” message is send instead to alert the HS.

6.2.9 Enable Automatic SLC Release

S347

If the HSG is in “audio connected” state and the HS initiates an audio release by “AT+CKPD=200” (“Button pressed”), the ACL will be released too if S-Register 347 = 1. If S347=0, it is up to the user to release the ACL manually by “AT+HSGH” or retain the

ACL by doing nothing.

6.2.10 AG Status

ATI64

Returns the status of the Audio Gateway (HSP) instance:

0 = not connected

1 = ACL connected

2 = Audio connected

5 = Alerting HS by sending “RING”

6 = Alerting HS by in-band ringing

6.2.11 AG Asynchronous Messages

CONNECT <bd_addr

An ACL connection to headset has been established.

<bd_addr

<uuid

: “1108” if it was an outgoing connection.

<dir> : “<”/”>”/”I”/”O”’ optionally indicates the direction (incoming/outgoing),

please refer to S331 and section 6, page 85

HSG”AU1”

Audio connection (SCO) has been established (= “audio on”).

HSG”AU0”

Audio connection (SCO) has been released (= “audio off”).

HSG”B”

“AT+CKPD=200” (”Button pressed”) was received from HS.

HSG”VGSn”

“AT+VGS=n” with was received from HS (speaker gain setting). The valid range for n is 0..15.

HSG”VGMn”

“AT+VGM=n” with was received from HS (microphone gain setting). The valid range for n is 0..15.

NO CARRIER 1112

ACL connection to local AG-instance has been released. Please note section 6, page 85, too.

> : Bluetooth address of headset device

hex

> : “1112” if it was an incoming connection

hex

>,<uuid

hex

>[,<dir>]

hex

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6.2.12 AG - HSP Summary (HSG)

Task AT-Command /

S Register

Enable HSP-AG role S102 0x08 = AG role of HSP (bitmask), needs subsequent

Initiate SLC from AG (HSP) AT+HSGD<bd_ad-

hex

Alert HS by RING or in-band ringing

Cancel alerting before answered by HS

Initiate audio / Transfer audio from AG to HS

Release audio connection / Transfer audio from HS to AG

Release audio and SLC from AGAT+HSGH or

Enable automatic alerting on ACL establishment

Enable in-band ringing S346 0 = disable in-band ringing

Enable automatic ACL release S347 0 =disable

Inquire AG status ATI64 0 = not connected

Table 3.27: Audio gateway role (HSP) – Summary of S Registers and AT Commands

AT+HSGC An existing SLC is required. RING / in-band-ringing is

AT+HSGCH HSG must be in alerting state (ATI64=5 or =6)

AT+HSGA An existing SLC is required

AT+HSGR Response:

ATH1112 or ATH*

S345 0 = disable auto alerting

Comment

“AT&W” and “atz” to activate

Responses: successful: “CONNECT 123456789012,1108,>” failed: “NO CARRIER” wrong state: “ERROR 63” prole disabled: “ERROR 59”

controlled by S346. Automatic alerting can be cong-

ured using S345.

HSG will stop sending RING-message or release audio

(in-band ringing)

successful: “OK” and “HSG”AU0” wrong state:” ERROR 63” prole/role disabled: “ERROR 59“

Response: successful: NO CARRIER 1112 (AG(HSP) was connected previously) wrong state:” ERROR 63” prole/role disabled: “ERROR 59“

1 = auto alerting on outgoing ACL established 2 = auto alerting on incoming ACL established 3 = auto alerting on outgoing and incoming ACL

established

1 = enable in-band ringing

1 = ACL will be released automatically when audio was

released by the HS.

1 = ACL connected 2 = Audio connected 5 = Ringing (ACL connected) 6 = In-band ringing (Audio connected)

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AT COMMAND SET REFERENCE

 7. HFP(Hands-FreeProle)

The Hands-free prole (HFP) denes how two devices supporting HFP shall interact with each other on a point-to-point basis. The use case for HFP is a hands-free unit that is connected wirelessly to an audio gateway. The audio gateway is typically a cellular phone. The hands-free unit acts as audio input and audio output of the cellular phone and allows to control typical telephony functions to be performed without access to the actual phone.

A BTM5xx module is required to be controlled by a host processor using AT commands (hosted operation mode). BTM5xx HFP implementation supports both Hands-free role and Audio gateway role.

An AT command beginning with AT+HF... indicates afliation to Hands-free role of HFP.

An AT command beginning with AT+HFG…indicates afliation to Audio Gateway role of HFP.

Version 1.5 of the hands-free prole is supported [5].

Table 3.28 below shows the feature requirements for this prole and the level of support on BTM5xx. It is highly recommended to download the prole specication [5] in order to understand the procedures related to a certain AT command. For quick navigation, references to [5] are given in this section which follow the syntax:

#<Feature>_<Section>

With:

<Feature> = HFP feature no. in Table 3.28 and Table 3.1 of [5]

<Section> = Appropriate Section in [5]

Example: #3_4.12

feature no. = 3, section = 4.12

HFP Feature Support in HF Support in AG

Specication BTM5xx Specication BTM5xx

1. Connection management M Yes M Yes

2. Phone status information M Yes M Yes

3. Audio Connection handling M Yes M Yes 4 Accept an incoming voice call M Yes M Yes

5. Reject an incoming voice call M Yes O Yes

6. Terminate a call M Yes M Yes

7. Audio Connection transfer during an ongoing call M Yes M Yes

8. Place a call with a phone number supplied by the HF O Yes M Yes

9. Place a call using memory dialing O Yes M Yes

10. Place a call to the last number dialed O Yes M Yes

11. Call waiting notication O Yes M Yes

12. Three way calling O (2) O (2)

13. Calling Line Identication (CLI) O Yes M Yes

14. Echo cancellation (EC) and noise reduction (NR) O (5) O (5)

15. Voice recognition activation O (5) O (5)

16. Attach a Phone number to a voice tag O (5) O (5)

17. Ability to transmit DTMF codes O (5) M (4)

18. Remote audio volume control O (1) O (1)

19. Respond and Hold O (2) O (2)

20. Subscriber Number Information O Yes M Yes 21a. Enhanced Call Status O (2) M Yes 21b. Enhanced Call Controls O (2) O (2)

M: mandatory O: optional

(1) support planned for future AT rmware release (2) support planned for future AT rmware release, but with low priority (3) not planned to be supported for future AT rmware (4) service level signalization only (5) support for service level signalization only planned for future AT rmware release

Table 3.28: Hands-free Prole supported features on BTM5xx

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7.1 Hands-Free Unit Role (HF)

Hands-free role is activated by setting ag 0x10 in S102 plus “AT&W” plus “atz“. Figure 3.24 outlines a block diagram with a BTM5xx in hosted operation mode.

Telephone control

Host

(e.g set of buttons /

Controller

keypad / display)

AT command interface

Audio

Speaker

Echo

BTM5xx [HF]

Microphone

Figure 3.24 Hands-free unit block diagram

7.1.1 Initiate Service Level Connection (SLC) from HF (#1_4.2)

AT+HFD<bd_addr

Initiate service level connection (SLC) from local hands-free instance to remote device with <bd_addr

the Hands-free prole (HFP).

Response:

SLC established: <cr,lf>CONNECT 123456789012,111F,><cr,lf>

Failed: <cr,lf>NO CARRIER<cr,lf>

Or: <cr,lf>ERROR 59<cr,lf>

Or: <cr,lf>ERROR 63<cr,lf>

After a SLC connection has been established, the module remains in AT command mode. S Register 531 is ignored for HFP connections.

>. The remote device must support the audio gateway role (AG) of

hex

Cancellation

hex

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7.1.2 Initiate Audio Connection from HF (#3_4.11)

AT+HFA

Initiate audio connection from local Hands-free instance. An existing service level connection is required.

Response:

Audio on: <cr,lf>HF”AU1”<cr,lf>

7.1.3 Release Audio Connection from HF (#3_4.12)

AT+HFR

Release audio connection only. The service level connection will be retained.

Response:

Audio on: <cr,lf>HF”AU0”<cr,lf>

7.1.4 Release Entire Connection from HF (#1_4.3)

AT+HFH

Release connection from local Hands-free instance. Audio connection will be released if existing, SLC will be released anyway.

Response:

On audio disconnection: <cr,lf>HF”AU0”<cr,lf> (only if audio connection exists)

On SLC disconnection: <cr,lf>NO CARRIER 111E<cr,lf>

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7.1.5 Answer Incoming Call from HF (#4_4.13)

AT+HFCA

Answer an incoming call. “ATA” will be sent to the AG. In return, the audio gateway shall update its “+CIEV” indicators (“call=1” and “callsetup=0”) and send appropriate messages to the HF. Upon receipt of a “+CIEV” message, HF will notify its host by a “HFI<indicator>,<value>”

message. Please refer to section 7.1.15 on page 64.

7.1.6 Reject Incoming Call from HF/Terminate Call from HF (#5_4.14;#6_4.15)

AT+HFCH

Reject incoming call/terminate ongoing call. “AT+CHUP” will be sent to the AG. In return, the audio gateway shall update its indicator “call”=0 and send the appropriate “+CIEV” message to the HF. HF will notify its host by a “HFI<indicator>,<value>” message. Please

refer to section 7.1.15 on page 64.

7.1.7 Place Call with Number Provided by HF (#8_4.18)

AT+HFC”nnn”

Initiate a new call from HF to the number specied by the number string “nnn”. This command will send “ATDnnn” to the audio gateway.

7.1.8 Memory Dialing from the HF (#9_4.19)

AT+HFCM”mmm”

Initiate a new call from HF to the number stored in memory location “mmm” of the AG. This command will send “ATD>mmm” to the audio gateway.

7.1.9 Re-Dial Last Number from HF (#10_4.20)

AT+HFCL

Initiate a new call from HF to the number last dialled by AG. “AT+BLDN” will be sent to the AG. In return, the audio gateway shall update its indicator “callsetup”=2 and send the appropriate “+CIEV” message to the HF. HF will notify its host by a “HFI<indicator>,<value>”

message. Please refer to section 7.1.15 on page 64.

  7.1.10 EnableCallerLineIdenticationPresentation–CLIP(#13_4.23)

The CLIP feature is enabled by setting Bit 2 (value=4) in the HF supported features S register 581. Subsequent AT&W and ATZ is required to take effect. If this bit is set at boot time, the following actions are carried out automatically:

1. The according ag is set in the HF service record.

2. The according ag is set in the BRSF-message on Service Level Connection establishment

3. The SLC message “AT+CLIP=1” is sent automatically once the SLC is established

Response to action no. 3 will be indicated by either HF”CLIP,OK” or HF”CLIP,ERROR” after the “CONNECT…” message.

 7.1.11EnableCallWaitingNotication–CCWA(#11_4.21)

The CCWA feature is enabled by setting Bit 1 (value=2) in the HF supported features S register 581. Subsequent AT&W and ATZ is required to take effect. If this bit is set at boot time, the following actions are carried out automatically:

1. The according ag is set in the HF service record.

2. The according ag is set in the BRSF-message on Service Level Connection establishment

3. The SLC message “AT+CCWA=1” is sent automatically once the SLC is established

Response to action no. 3 will be indicated by either HF”CCWA,OK” or HF”CCWA,ERROR” after the “CONNECT…” message.

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7.1.12 Query Subscriber Number from HFG (#20_4.30)

AT+HFS?

Query subscriber numbers from HFG. “AT+CNUM” is sent to the HFG. HFG will send the subscriber number information, indicated on the HF by HF”+CNUM,,,””. An “OK” will be sent by HFG on termination, indicated on HF by the asynchronous message HF”CNUM,OK”. If the HFG does not support this feature, it should send ERROR, indicated on HF as HF”CNUM,ERROR”.

Refer to section 7.1.17 on page 64.

Response:

<cr><lf>OK<cr><lf> (immediately, BTM accepting command)

and one of the following:

<cr><lf>HF”+CNUM:<number>,<type>,<service>”<cr><lf> (refer to section 3.2.7.1.17)

<cr><lf>HFX”<SLC_message>”<cr><lf> (original SLC response from HF gateway, but response format not compliant to HFP specication)

<cr><lf>HF”CNUM,ERROR” <cr><lf> (feature not supported by HF-gateway)

Nothing, if the HF-gateway is ignoring this query for any reason

7.1.13 Query Operator Selection (#2_4.8)

AT+HFO?

Query operator selection from HFG. “AT+COPS?” is sent to the HFG. HFG will send the operator selection information, indicated on the HF by HF”+COPS,,,””. An “OK” will be sent by HFG on termination, indicated on HF by the asynchronous message HF”COPS,OK”.

If the HFG does not support this feature, it should send ERROR, indicated on HF as

HF”COPS,ERROR”. Refer to section 7.1.17 on page 64.

Response:

<cr><lf>OK<cr><lf> (immediately, BTM accepting command)

And one of the following:

<cr><lf>HF”+COPS:<mode>,<operator_size>,<operator>”<cr><lf> (refer to section 7.1.17 on page 64)

or:

<cr><lf>HF”COPS,ERROR”<cr><lf>

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7.1.14 Enable Extended Error Codes in HFG – CMEE (#2_4.9)

AT+HFE1

Enable operator selection from HFG. “AT+CMEE=1” is sent to the HFG. HFG will respond with “OK”, indicated at the HF by HF”CMEE,OK” or “ERROR” indicated at the HF by HF”CMEE,ERROR”

Response:

<cr><lf>OK<cr><lf> (immediately, BTM accepting command)

And one of the following:

<cr><lf>HF”CMEE,OK”<cr><lf> (conrmation from HFG)

or:

<cr><lf>HF”CMEE,ERROR”<cr><lf> (error, e.g. not supported by HFG)

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7.1.15 “+CIEV” Indicators Received from AG (#2)

HFI”<indicator_string>”,<val> (S333=1, default)

HFI<indicator_id>,<val> (S333=0)

Inform the HF-host about a “+CIEV” indicator message received from the connected audio

gateway. S-Register 333 enables verbose mode for HFI indicators. Possible indicators are listed in Table 3.29.

“+CIEV” Audio

Gateway Indicator

Service “service” 1 4.4

Call “call” 2 All call related sections

Call Setup “callsetup” 3

Call held “callheld” 4

Signal “signal” 5 4.5

Roam “roam” 6 4.6

Battery Charge “battchg” 7 4.7

7.1.16 Hands-Free Status

ATI65

Returns the status of the Hands-free (HFP) instance:

0 = not connected

1 = SLC connected

2 = Audio connected

3 = In call, SLC connected

4 = In call, audio connected

HFI indicator_string

(S333=1)

Table 3.29: +CIEV indicators in HFI message

HFI indicator_id

(S333=0)

Section in HFP spec. [5]

7.1.17 Hands-Free Asynchronous Messages

CONNECT <bd_addr

A Service level connection to headset has been established and initialized.

<bd_addr

<uuid

“111F” if it is an outgoing connection.

<dir> : “<”/”>”/”I”/”O”’ optionally indicates the direction (incoming/outgoing),

please refer to S331 and section 6, page 85

HF”RING”

HF has received a “RING” indication from the connected audio gateway. HF is expected to respond with “ATA” (answer, see “AT+HFCA”) or “AT+CHUP” (see “AT+HFCH”).

HF”ERROR”

HF has received “ERROR” from the connected audio gateway. This can be due to a request for memory dialling with invalid memory location (AT+HFC>”mmm”) or due to a request to redial the last number (AT+HFDL) but there is no last number available in the AG.

HF”AU1”

Audio connection (SCO) has been established (= “audio on”).

HF”AU0”

Audio connection (SCO) has been released (= “audio off”).

HF”CLIP,OK”

HFG has replied with OK to reception of “AT+CLIP=1” or “AT+CLIP=0”.

> : Bluetooth address of headset device

hex

> : “111E” if it is an incoming connection

hex

>,<uuid

hex

>[,<dir>]

hex

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AT COMMAND SET REFERENCE

HF”CLIP,ERROR”

HFG has replied with ERROR to reception of “AT+CLIP<…>”.

HF”+CLIP,n,m,1234567”

A “calling line identication notication” (+CLIP:”1234567”,<type>) has been received from the HFG. This message is sent by the HFG on incoming calls together with HF”RING”. The HFG and telephone network must support this feature and the according ag (Bit 2) in

the HF supported features S register 581 must be set at boot time.

n = type of number (derived from the <type> in SLC message, not the original value):

0 – unknown

1 – international number

2 – national number

3 – network specic number

4 - dedicated access, short code

m = length of caller number (number of characters)

1234567 = caller number

HF”CCWA,OK”

HFG has replied with OK to reception of “AT+CCWA=1” or “AT+CCWA=0”.

HF”CCWA,ERROR”

HFG has replied with ERROR to reception of “AT+CCWA<…>”.

HF”+CNUM:’1234567’,ttt,s”

Response to a AT+CNUM request received from HFG:

1234567 – phone number in format specied by ttt

ttt – species the format of the phone number provided, and can be one of the following values:

- values 128-143: The phone number format bay be a national or international format, and may contain prex and/or escape digits. No changes on the number presentation

are required.

- values 144-159: The phone number format is an international number, including country code prex. If the plus sign (“+”) is not included as part of the number and

shall be added by the HFG as needed.

- values 160-175: National number. No prex nor escape digits included.

s – Indicates which service this phone number relates to. Shall be either 4 (voice) or 5 (fax).

HF”CNUM,OK”

HFG has replied with OK to reception of AT+CNUM (subscriber number information query).

HF”CNUM,ERROR”

HFG has replied with ERROR to reception of AT+CNUM (subscriber number information query). A reason might be that this feature is not supported by the HFG.

HF”+COPS:m,ss,Operator”

Response to a AT+COPS? request received from HFG:

m – contains the current mode and contains no information with regard to the name

of the operator.

ss – size of the operator name in characters

Operator – the name of the network operator in alphanumeric format

HF”COPS,OK”

HFG has replied with OK to reception of “AT+COPS?”.

HF”COPS,ERROR”

HFG has replied with “ERROR” to reception of “AT+COPS”.

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HF”CMEE,OK”

HFG has replied with OK to reception of “AT+CMEE=1”.

HF”CMEE,ERROR”

HFG has replied with “ERROR” to reception of “AT+CMEE=1”.

HFI<…>

Indicator (+CIEV…) from audio gateway was received. Refer to section 7.1.15 on page 64.

NO CARRIER 111E

Service level connection to local HF-instance has been released. Please note section 6, page 85, too.

7.1.18 Hands-free summary

Task AT-Command / S

Enable HFP-HF role S102 0x10 = HF role of HFP (bitmask), needs subsequent

Initiate SLC from HF AT+HFD<bd_ad-

hex

Initiate audio connection from HF AT+HFA Responses:

Release audio only from HF / Transfer Audio to AG

Initiate call with number provided by HF

Initiate call with number provided by memory of AG

Initiate call to last dialled number AT+HFCL Response:

Disconnect SLC from HF (and audio if exists)

Enable verbose indicators S333 0 – display indicator ID only in HFI.. asynchronous

Set HF supported features S581 Bitmask

Inquire HF status ATI65 0 = not connected

Table 3.30: Hands-free role (HFP) – Summary of S Registers and AT Commands

AT+HFR Responses:

AT+HFC”nnn” “nnn” = number string

AT+HFCM”mmm” “mmm” = memory location in AG of number

AT+HFH / ATH111E

/ ATH*

Comment

“AT&W” and “ATZ” to activate

Responses: successful: “CONNECT 123456789012,111F,>” failed: “NO CARRIER” prole disabled: “ERROR 59” incorrect state: “ERROR 63”

HF“AU1”

HF“AU0”

requested to dial

HFI”callsetup”,2 – conrmation, call is being set up OR: HFG”ERROR” - last dialled number not available

in AG

Please note section 4, page 83 and section 6, page 85

message (refer to Section 7.1.15 on page 64) 1 – display indicator string in HFI… asynchronous message (refer to Section 7.1.15 on page 64)

Bit 1 – call waiting notication capability Bit 2 – CLIP presentation capability

Other options are not supported by the current

rmware

1 = SLC connected 2 = Audio connected 3 = in call - SLC 4 = in call - audio

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AT COMMAND SET REFERENCE

7.2 Audio Gateway Role (AG-HFP / HFG)

Audio gateway role is activated by setting ag 0x40 in S102 plus “AT&W” plus “atz“. Please refer to Figure 3.23 (page 56) for a block diagram of an audio gateway with a BTM5xx in hosted

operation mode.

Table 3.28 shows the feature requirements for this prole and the level of support on BTM5xx. It is highly recommended to download the prole specication [5] in order to understand the procedures related to a certain AT command. For quick navigation, references to [5] are given in this section which follow the syntax:

#<Feature>_<Section>

With:

<Feature> = HFP feature no. in Table 3.28 and Table 3.1 of [5]

<Section> = Appropriate Section in [5]

Example: #3_4.12

feature no. = 3, section = 4.12

7.2.1 Initiate Service Level Connection (SLC) from AG (#1_4.2)

AT+HFGD<bd_addr

Initiate service level connection (SLC) from local audio gateway instance to remote device with <bd_addr

Hands-free prole (HFP).

Response:

SLC established: <cr,lf>CONNECT 123456789012,111E,><cr,lf>

Failed: <cr,lf>NO CARRIER<cr,lf>

Or: <cr,lf>ERROR 59<cr,lf>

Or: <cr,lf>ERROR 63<cr,lf>

After an SLC connection has been established, the module remains in AT command mode. S Register 531 is ignored for HFP connections.

hex

>. The remote device must support the Hands-free role (HF) of the

7.2.2 Initiate Audio Connection from AG (#3_4.11)

AT+HFGA

Initiate audio connection from local audio gateway instance. An existing service level connection is required.

Response:

Audio on: <cr,lf>HFG”AU1”<cr,lf>

7.2.3 Release Audio Connection from AG (#3_4.12)

AT+HFGR

Release audio connection only. The service level connection will be retained.

Response:

Audio on: <cr,lf>HFG”AU0”<cr,lf>

7.2.4 Release Entire Connection from AG (#1_4.3)

AT+HFGH

Release connection from local audio gateway instance. An ongoing call will be terminated and a audio connection will be released if existing, SLC will be released anyway.

Response:

On audio disconnection: <cr,lf>HFG”AU0”<cr,lf> (only if audio connected)

On SLC disconnection: <cr,lf>NO CARRIER 111F<cr,lf>

Please also refer to Section 6, page 85.

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7.2.5 Signal Incoming Call from AG to HF (#4_4.13)

AT+HFGC”<number_string>”,<type

Signal an incoming call by sending “RING” and “+CLIP:”<number_string>”,<type to HF periodically. The <number_string> eld represents the phone number of the ringing party. The type eld species the format of the phone number provided, and can be one of the following values:

• values 128-143: The phone number format may be a national or international format, and may contain prex and/or escape digits. No changes on the number presentation

are required.

• values 144-159: The phone number format is an international number, including the country code prex. If the plus sign (“+”) is not included as part of the number and

shall be added by the AG as needed.

• values 160-175: National number. No prex nor escape digits included.

Please refer to the Hands-free Prole Specication [5].

The HF is now expected to answer or to reject the call. Optionally, an incoming call can be answered or rejected at the AG side.

7.2.6 Signal Outgoing Call Status from AG to HF (#8_4.18; #9_4.19; #10_4.20)

AT+HFGC1

Signal an outgoing call status by sending “+CIEV:3,2” (callsetup=2) indicator to HF. If an audio connection is not present yet, it will be initiated.

An outgoing call can be initiated by HF and is indicated on the AG side by the following

asynchronous messages:

• HFG”Dnnn” (dial number <nnn> given by headset)

• HFG”D>nnn” (dial from AG memory location nnn)

• HFG”L” (redial last number)

AT+HFGC2

Signal to HF that remote party was reached and is being alerted during an outgoing call setup procedure. “+CIEV:3,3” (callsetup=3) indicator is sent to HF. If the wireless network does not provide an indication of alerting the remote party, the AG may not send this indication.

AT+HFGC3

Signal to HF that remote party has answered the call. “+CIEV:2,1” (call=1) and “+CIEV:3,0” (callsetup=0) indicators is sent to HF subsequently.

dec

>”

dec

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7.2.7 Signal Termination of a Call from AG to HF (#6_4.15)

AT+HFGCH

Signal termination of a call by sending “+CIEV:2,0” (call=0) indicator to HF. This command can also be used during a call setup procedure. This would then indicate the interruption / cancellation of the ongoing call setup procedure for any reason.

7.2.8 Sending AG Indicators to HF (“+CIEV…”, #2)

AT+HFGI<indicator_id

Send an AG indicator to HF in the form “+CIEV:<indicator_id>,<value>”

Table 3.31 lists possible indicators and their value range.

If there is no SLC existing and indicator “Service” is set (AT+HFGI1,n), the value is stored in volatile memory in order to be presented during a future SLC initialization procedure.

For all other indicators, this command is valid only if a SLC exists. For call management purposes the appropriate commands above (AT+HFGCx) should be used. They will send indicators automatically.

>,<value

dec

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Indicator name indicator_id Range of value Section in HFP spec. [5]

Service 1 0..1 4.4

Call 2 0..1 All call related sections

Call setup 3 0..3

Call held 4 0..2

Signal 5 0..5 4.5

Roam 6 0..1 4.6

Battery Charge 7 0..5 4.7

Table 3.31: AG indicators for “AT+HFGI..”

7.2.9 Send Operator String to HF (“+COPS…”, #2_4.8)

AT+HFGO”<operator_string>”

Send network operator string to HF by “+COPS:0,0,”<operator_string>” on SLC. This command shall be used to respond to a “AT+COPS?” request, indicated by the asynchronous message HFG”OP?”.

7.2.10 Send “ERROR” or “+CME ERROR…” to HF

AT+HFGE<cme_code>

Send “ERROR” to HF if no <cme_code> is given. Required as optional response to HFG”D>nnn” an HFG”L”.

If the optional <cme_code> is appended and if extended AG error result codes were

enabled by HF (stored internally), the appropriate extended error result code in the form of +CME ERROR: <cme_code> is sent to HF.

If <cme_code> is appended but extended error codes have not been enabled by HF,

<cme_code> is ignored and only “ERROR” is sent to HF.

7.2.11 Subscriber Number Records (“+CNUM…”, #20_4.30)

AT+HFGS=”<number_string>”,<type>,<service>

This command adds a subscriber number record to the HFG. The subscriber number is the telephone number of the HFG. It is allowed to have more than one subscriber numbers. All subscriber numbers available should be stored in the HFG immediately after power up of the system. As soon as an SLC to a HF device is established, the HF can query the HFG’s subscriber numbers at any time by sending “AT+CNUM” to the HFG on the SLC. The subscriber number records existing at that time will be sent to the HF automatically then. Subscriber number records are stored in volatile memory. Hence they are lost on reset or power cycle.

<number_string> = subscriber number string, characters allowed: 0123456789*#+ABDCTP!W@

<type> = species the format of <number_string> provided, can be one of the following values:

• values 128-143: The phone number format may be a national or international format, and may contain prex and/or escape digits. No changes on the number presentation

are required.

• values 144-159: The phone number format is an international number, including the country code prex. If the plus sign (“+”) is not included as part of the number and

shall be added by the AG as needed.

• values 160-175: National number. No prex nor escape digits included.

<service> = service of this subscriber number, permitted values:

4 – voice

5 – fax

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Response:

<cr><lf>OK<cr><lf> command valid, record added

OR:

<cr><lf>ERROR 05<cr><lf> syntax or value range error

OR:

<cr><lf>ERROR 67<cr><lf> maximum number of subscriber number records reached

AT+HFGS?

This command returns a list of currently available subscriber number records which would

be sent to the HF-unit on request (“AT+CNUM” issued by HF on the SLC).

Response:

For each subscriber number record (if at least one is available):

And nally:

<cr><lf>OK<cr><lf> command nished

With:

<index> = current index of the record, required as parameter n for AT+HFGSD<n>

<number_string> = subscriber number string

<type> = species the format of <number_string>, refer to “AT+HFGS=…” above

<service> = service of this subscriber number:

4 – voice

5 – fax

AT+HFGSD

Delete all subscriber number records in the HFG.

Response:

AT+HFGSD<n>

Delete subscriber number record with index <n> in the HFG. <n> refers to the index that is displayed on HFGS?. <n> is assumed to be one digit. The index is not xed to a record. If there are higher numbered indexes than the one deleted, the remaining records will get a new index assigned dynamically on HFGS?.

Response:

Or:

<cr><lf>ERROR 66<cr><lf> record with requested index <n> not available

Or:

<cr><lf>ERROR 05<cr><lf> syntax error

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7.2.12 Audio Gateway (HFP) - Asynchronous Messages

CONNECT <bd_addr

A Service level connection to headset has been established and initialized.

<bd_addr

<uuid

“111E” if it is an outgoing connection.

<dir> : “<”/”>”/”I”/”O”’ optionally indicates the direction (incoming/outgoing),

please refer to S331 and section 6, page 85

> : Bluetooth address of headset device

hex

> : “111F” if it is an incoming connection

hex

>,<uuid

hex

>[,<dir>]

hex

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AT COMMAND SET REFERENCE

HFG”VGS<n>”

Speaker gain setting message was received from HF (“+VGS:<n>”) with n = gain [0..15].

HFG”VGM<n>”

Microphone gain setting message was received from HF (“+VGM:<n>”) with n = gain [0..15].

HFG”AU1”

Audio connection (SCO) has been established (= “audio on”).

HFG”AU0”

Audio connection (SCO) has been released (= “audio off”).

HFG”C”

A call has been established and is ongoing.

HFG”T”

A call has been terminated.

HFG”R”

Incoming call was rejected by HF.

HFG”OP?”

Request for network operator string (“AT+COPS?”) received from HF. AG is expected to reply with “+COPS:0,0,<operator_string>” on SLC. Use AT+HFGO”<operator_string>”.

HFG”Dnnn”

Request from HF to place an outgoing call to phone number provided by HF with <nnn> = number string. The AG is expected to conrm the outgoing call with the command AT+HFGC1.

HFG”D>nnn”

Request from HF to place an outgoing call using memory dialling with <nnn> = memory location. The AG is expected to either conrm the outgoing call with the command

AT+HFGC1 or to respond with AT+HFGE if the memory location is invalid.

HFG”L”

Request from HF to place an outgoing call using the last number dialled. The AG is expected to either conrm the outgoing call with the command AT+HFGC1 or to respond with AT+HFGE if the last number dialled is not available.

HFG”Mn”

Request from HF to generate DTMF code <n> towards the telephony network.

HFG”CLIP1”

Request to activate caller line identication notication in the AG.

HFG”CCWA1”

Request to activate call waiting notication in the AG.

HFG”CMEE1”

Request to activate extended AG error result codes in the form +CME ERROR: <err>.

NO CARRIER 111F

Service level connection to local HFG-instance has been released. Please note section 6, page 85.

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AT COMMAND SET REFERENCE

7.2.13 AG - HFP summary (HFG)

Task AT-Command / S Register Comment

Enable HFP-AG role S102 0x40 = AG role of HFP (bitmask), needs subsequent

Initiate SLC from HFG AT+HFGD<bd_addr

Initiate audio connection from AG / Transfer Audio from AG to HF

Release audio only from AG / Transfer Audio from HF to AG

Disconnect SLC from HFG (and audio if exists)

Signal incoming call to HF AT+HFGC”<number_

Signal outgoing call status to HF AT+HFGC1 Outgoing call is being initiated by AG as result of a

Signal termination of a call or a call setup procedure to HF

Send AG indicator status to HF

(+CIEV…)

Send network operator string to HF AT+HFGO”<operator_

Send error to HF AT+HFGE Sends “ERROR” to HF. Needed on HFG”D>mmm” if

Send extended error result code to HF

Enable verbose indicators S333 0 – display indicator ID only in HFI.. asynchronous

Inquire HFG status ATI66 0 = not connected

AT+HFGA Response:

AT+HFGR Response:

AT+HFGH / ATH111F /

ATH*

string>”,<type

AT+HFGC2 Outgoing call:

AT+HFGC3 Outgoing call:

AT+HFGCH Command also used to inform HF about remote

AT+HFGI<indicator_ id

>,<value

dec

string>”

AT+HFGE<cme_code

hex

dec

“AT&W” and “ATZ” to activate

> Responses:

Successful:“CONNECT 123456789012,111F,>” failed: “NO CARRIER” prole disabled: “ERROR 59” incorrect state: “ERROR 63”

HFG“AU1”

HFG“AU0”

Please note section 4, page 83 and section

Sends “RING” and “+CLIP: <number_string>, <type>”

to HF <type> must be in range 128..175 Refer to section 7.2.5 on page 68

HF request . Use this AT command as positive

conrmation of: HFG”Dnnn” or HFG”D>mmm” or HFG”L”

Remote party has been reached and is being alerted

Remote party has answered the call

rejection of outgoing call

For <indicator_id> and <value> see Table 3.31. Command is recommended to be used only with

indicator IDs 1, 5, (6) and 7. For all other commands

the appropriate call managing AT commands are recommended. They send the indicators automatically.

Command used to respond to HFG”OP?”

memory location is invalid or on HFG”L” if last dialled

number not available

> “+CME ERROR: <cme_code

did enable this feature earlier. Otherwise a simple

“ERROR” is sent to HF.

message (Section 7.1.15 on page 64) 1 – display indicator string in HFI… asynchronous

message (Section 7.1.15 on page 64)

1 = SLC connected 2 = Audio connected 3 = in call - SLC 4 = in call – audio

>” is sent to HF if HF

dec

6, page

Table 3.32: AG-HFP (HFG) – Summary of S Registers and AT Commands

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AT COMMAND SET REFERENCE

 8. DUN(Dial-UpNetworkingProle)

The Dial-up networking prole (DUN,[6]) denes protocols and procedures for the dial-up networking use case. Scenarios are the usage of a wireless modem or a cellular phone for dial–up Internet

connections or the usage of a wireless modem or cellular phone to receive data calls by a PC.

There are two roles dened:

1.) Gateway (GW)-This device provides access to the public network (e.g., cellular phone or modem),

and role is not supported on BTM.

2.) Data Terminal (DT)-This device uses the dial-up services of the Gateway (e.g., PC), and is supported on BTM.

In order to map these roles to the conventional modem structure, the Gateway is referred to as Data

Circuit Endpoint (DCE), and the Data Terminal is referred to as Data Terminal Endpoint (DTE).

A BTM module is required to be controlled by a host processor using AT commands (hosted operation mode). BTM DUN implementation supports DT role only.

The DUN prole belongs to the group of serial stream oriented proles (SSO). The appropriate

implications and restrictions are described on page 24.

An AT command beginning with AT+DU... indicates afliation to the DUN prole.

Service Support in DT Support in GW

Specication BTM Specication BTM

1. Data call without audio feedback M Yes M No

2. Data call with audio feedback O No O No

3. Fax services without audio feedback N/A No N/A No

4. Fax services with audio feedback N/A No N/A No

5. Voice call N/A No N/A No

M: mandatory O: optional N/A: not applicable

  8.1 ProleActivation

DUN prole is activated by setting ag 0x04 in S102 plus “AT&W” plus “ATZ“.

8.2 Initiate DUN Connection

AT+DUD<bd_addr

Initiate ACL connection to remote device with <bd_addr

DUN prole (HSP).

Response: <cr,lf>CONNECT 123456789012,1103,><cr,lf>

Or: <cr,lf>NO CARRIER<cr,lf>

Or: <cr,lf>ERROR 59<cr,lf>

Or: <cr,lf>ERROR 63<cr,lf>

Or: <cr,lf> ERROR 65<cr,lf>

After an DUN connection has been established, the module changes its mode to the mode

dened by S Register 531. The recommended value is S531=0 for a DUN connection (=default). Before initiating a DUN connection, S507 must be set to 2 (ats507=2). This will cause the module

to escape from connected mode to command mode by toggling DSR line only. An escape sequence of “^^^” is not compliant with the DUN specication. S507=2 also congures the module for high data throughput.

Once the Bluetooth connection is established all data arriving at the UART is transferred to the gateway, hence any AT commands will be transferred directly to the gateway. Now the host can

e.g. dial in to the internet provider by “ATD123456” as if directly connected to a serial modem.

hex

>. The remote device must support the

hex

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AT COMMAND SET REFERENCE

8.2.1 Release DUN Connection

AT+DUH

The module must be in command mode so that AT-commands will be parsed. If the

module is in data mode (S531=0, S507=2), toggle DSR line to change into command mode. <cr><lf>OK <cr><lf> will be sent to the host to conrm that that module is in command mode. Toggling DSR means to de-assert (deactivate) an and assert (activate) the DSR line within a time specied by S519 which is 500 ms per default. Hence DSR needs to be asserted at the time of AT+DUD<BdAdd>, if data mode with S531=0 and S507=2 or S507=1 is congured.

DSR asserted means a voltage level of logic 0 (0.0 V) at the module pin, because the UART

level shifter inverts the signal. Accordingly, DSR de-asserted means a voltage level of logic

1 (3.3 V) at the module pin.

Response:

On Bluetooth disconnection: <cr,lf>NO CARRIER 1103<cr,lf>

Task AT-Command / S Register Comment

Enable DUN prole S102 0x04 = DUN (bitmask),

needs subsequent “AT&W” and “ATZ” to activate

Set up escape mode via DSR, high throughput

Initiate DUN connection AT+DUD<bd_addr

Release DUN connection AT+DUH Responses:

ATS507=2 Needs subsequent “AT&W” if desired as permanent

setting

> Responses:

hex

Table 3.33: DUN – Summary of S Registers and AT Commands

successful: “CONNECT 123456789012,1103,>” failed: “NO CARRIER” prole disabled: “ERROR 59” incorrect state: “ERROR 63”

successful: “NO CARRIER 1103” prole disabled: “ERROR 59” incorrect state: “ERROR 63”

Hardware Units (BTM510 / 511)

This section covers S-Registers and AT-Commands that are related to hardware units of a BTM510 or BTM511

device. For this section, please also refer to the bluecore data sheet [10] for more detailed information.

1. Audio Loopback Mode

For testing purposes, an audio loopback mode is available. In mode=1 audio input (ADC) and audio output (DAC) are connected directly. In mode = 2, the stereo audio input signal is fed through the Kalimba DSP with running SBC codec (encoder, decoder) and is directed back to the audio stereo output. Audio Loopback Mode is controlled with the new AT Command “AT+BTL”.

Task AT-Command / SRegister Comment

Set audio loopback mode AT+BTL<Mode> Mode:

0 = off 1 = on, ADC -> DAC 2 = on, ADC -> DSP -> DAC

Set sampling rate for Audio Loopback Mode

Table 3.39: Audio Loopback AT-commands and S-Registers

S419 [0..6], default=6 0 = 8 kHz

1 = 11.025 kHz 2 = 16 kHz 3 = 22.050 kHz 4 = 24 kHz 5 = 32 kHz 6 = 44.1 kHz

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2. Codec Gain

Analogue input and output gains (Input Amplier, Output Amplier, Figure 3.25) can be set to one of 23 steps called “Gain Level”. To each gain level, an overall gain (dBr) is assigned, according to

Table 3.34. The overall gain is formed by an analogue and a digital component as outlined in Table

3.34. Gain values can be specied either as gain level or as overall gain by separate S Registers. Please note that a pair of such S-Registers always updates the other corresponding S-Register

(e.g., S589 – S689 and S590 – S690).

For S689 and S690, the overall gain (dBr) must be entered multiplied by 10. If the input value doesn’t

match a gain table entry, the nearest possible value is set. The actually set value can be checked by reading back S689/S690. The value of S689/S690 is printed out multiplied by 10 in order to avoid non integer numbers.

The command class “AT+G…” enables incremental and decremental gain settings. The increment/ decrement command corresponds to one row up/down in the gain table (Table 3.34). The Gain level

registers S589/S689 and S590/S690 are not affected by increment/decrement commands. Instead,

the current gain level is cached and can be retrieved by “AT+G(I|O)?”. There are two further commands to restore the cached gain level from S589/S590 (“AT+G(I|O)R”) and to save the currently cached gain level to S589/S590 (“AT+G(I|O)S”).

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Figure 3.27: Stereo Audio Codec Block Diagram

Output Gain Level or

Input Gain Level

S589 or S590

22 +21.5 7 7

21 +18.0 6 7

20 +15.5 5 7

19 +12.0 4 7

18 +9.5 3 7

17 +6.0 2 7

16 +3.5 1 7

15 0 0 7

14 -3.0 0 6

13 -6.0 0 5

12 -9.0 0 4

11 -12.0 0 3

10 -15.0 0 2

Overall Gain (dBr)

S689 or S690

Digital

Component

Analogue

Component

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Output Gain Level or

Input Gain Level

S589 or S590

9 -18.0 0 1

8 -21.0 0 0

7 -23.5 15 0

6 -27.0 14 0

5 -29.5 13 0

4 -33.0 12 0

3 -35.5 11 0

2 -39.0 10 0

1 -41.5 9 0

0 -45.0 8 0

Task AT-Command /

SRegister

Set output gain level S589 [0..22],

default=15

Set output overall gain (dBr) S689

[-450..+215], default=0

Set input gain level S590 [0..22],

default=15

Set input overall gain (dBr) S690

[-450..+215], default=0

Increment current output gain level

Decrement current output gain level

Query current output gain level

Restore current output gain level from S589

Save current output gain level to S589

Increment current input gain level

Decrement current input gain level

Query current input gain level

Restore current input gain level from S590

Save current input gain level to S590

AT+GOU Error 57 may appear if maximum gain level reached

AT+GOD Error 58 may appear if minimum gain level reached

AT+GO?

AT+GOR

AT+GOS

AT+GIU Error 57 may appear if maximum gain level reached

AT+GID Error 58 may appear if minimum gain level reached

AT+GI?

AT+GIR

AT+GIS

Table 3.41: Gain Settings AT commands and S-Registers

Overall Gain (dBr)

S689 or S690

Table 3.40: Gain Table

Digital

Component

Comment

See Gain Table; S689 is affected, too

See Gain Table; value must be entered (and is returned) multiplied by 10; S589 is affected, too

See Gain Table; S690 is affected, too

See Gain Table; value must be entered (and is returned) multiplied by 10; S590 is affected, too

Analogue

Component

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3. Mic Input Gain

A microphone preamplier which adds extra 24dB to input gain, is controlled by S-Register 415. The microphone amplier is enabled by ATS415=1 and disabled by ATS415=0. Refer to Table 3.43. The rst amplier in Figure 3.28 represents the microphone preamplier and the second amplier represents the analogue component of the programmable audio input gain (refer to Table 3.40).

Figure3.28:ADCAnalogueAmplierBlockDiagram

4. LED Control

The module provides two dedicated output pins for LEDs (LED0, LED1). The following modes are supported: LED_OFF, LED_ON, LED_PWM and LED_PULSE.

In LED_PWM mode, the parameters “Duty Cycle” an “PWM Period” can be specied via S-Registers. This enables either to dim the brightness of an LED (PWM Period=0) or to specify blinking with dened on-time in a dened period (PWM Period > blinking visible for the eye).

In LED_PULSE mode, the brightness of an LED is modulated. Modulation speed is dened by parameter “Pulse Rate” and maximum brightness is dened by parameter “Duty Cycle”.

Task AT-Command / SRegister Comment

Set LED 0 mode S335 [0..3], default=0 Mode:

Set LED 1 mode S340 [0..3], default=0

Set LED 0 Duty Cycle S336 [0..4095], default = 2048 referenced if LED mode =

Set LED 1 Duty Cycle S341 [0..4095], default = 2048

Set LED 0 PWM Period S337 [0..15], default = 0 referenced if LED mode =

Set LED 1 PWM Period S342 [0..15], default = 0

Set LED 0 Pulse Rate S338 [0..15], default = 0 referenced if LED mode =

Set LED 1 Pulse Rate S343 [0..15], default = 0

Table 3.42: LED S-Registers

0 = LED_OFF 1 = LED_ON 2 = LED_PWM 3 = LED_PULSE

LED_PWM or LED_PULSE

LED_PWM

LED_PULSE

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5. Hardware Units - S Registers

Table 3.43 below gives an overview on S Registers for hardware units except GPIO. For GPIO Registers please refer to Table 3.45.

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S415 0 0..1 Enable Microphone Input Gain, adds extra 24dB to input gain

S419 6 0..6 Set sampling rate for Audio Loopback:

0 = 8 kHz 1 = 11.025 kHz 2 = 16 kHz 3 = 22.050 kHz 4 = 24 kHz 5 = 32 kHz 6 = 44.1 kHz

S589 15 0..22 Codec output gain level (index of gain table)

S590 15 0..22 Codec input gain level (index of gain table)

S689 0 -450..215 Set codec output gain in dBr * 10

(applies to sink), default = 0

S690 0 -450..215 Set codec input gain in dBr * 10

(applies to source), default = 0

S335 0 0..3 Set LED0 mode

0 = LED_OFF 1 = LED_ON 2 = LED_PWM 3 = LED_PULSE

S336 2048 0..4095 Set LED 0 Duty Cycle,

referenced if LED mode = LED_PWM or LED_PULSE

S337 0 0..15 Set LED 0 PWM Period, referenced if LED mode = LED_PWM

S338 5 0..15 Set LED 0 Pulse Rate, referenced if LED mode = LED_PULSE

S340 0 0..3 Set LED1 mode

0 = LED_OFF 1 = LED_ON 2 = LED_PWM 3 = LED_PULSE

S341 2048 0..4095 Set LED 1 Duty Cycle,

referenced if LED mode = LED_PWM or LED_PULSE

S342 0 0..15 Set LED 1 PWM Period, referenced if LED mode = LED_PWM

S343 5 0..15 Set LED 1 Pulse Rate, referenced if LED mode = LED_PULSE

Table 3.43: S Registers for Hardware Units

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6. GPIO

On a BTM device a number of digital I/Os can be used for general purposes. Each GPIO will be assigned

to an S-Register (S651 to S663) which will be capable of both GPIO conguration (cong mode) as well as single pin read/write access (r/w mode). The bitmask of the I/O pin for direct read/write access will be 0x01. All conguration ags are allocated to higher value bits. A bitmask for the I/O pin will be

applied to if new S-Register 650 is set to 1. This will enable the user to access a GPIO-Pin directly by

reading/writing 0 or 1. If the GPIO shall be congured, S650 must be set to 0 in order to obtain access to the GPIO conguration ags.

All logical GPIO lines can be read/written in one atomic step by new S-Register 670 at any time.

Some GPIOs can have an alternative function assigned. If the alternative function is enabled, the appropriate I/O Pin is not available as GPIO any more. Handshaking functions are generally enabled per default. Wi-Fi coexistence functions are currently not used. But if they should be used or required in the future, the appropriate function cannot be moved to another I/O Pin. Hence it should be considered that no other user function is assigned to an I/O Pin if the coexistence functions are required. The following table lists all GPIOs and their alternative functions.

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GPIO Pin

(BTM510/511)

GPIO1 - BT_Active (1)

GPIO2 DCD -

GPIO3 DSR -

GPIO4 RI -

GPIO5 - BT_State/BT_Priority

GPIO6 - Wlan_Active

GPIO7 - Rf_Active

GPIO8 DTR -

(1) BT_Active = RxEnable OR TxEnable

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

function mapping code / av_operation_id Reserved FMS FME INV DIR PS

Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Field Description

0 – PS I/O Pin State – returns the current state of the I/O pin (0/1) when read

A write affects the I/0 pin directly if DIR=1 and FME=0.

1 – DIR Direction – controls if the I/O pin is an input or an output.

0 input 1 output

2 – INV Inversion – controls if the I/O pin is inverted or not. Applies to both pin directions

(read and write).

0 not inverted 1 inverted

3 – FME Function Mapping Enable – Enables function mapping of the pin. A function

mapping code or an av_operation_id must be set in GPIO conguration register [8:15]. The pin will carry out the assigned operation and is not accessible anymore

as GPIO. 0 disable function mapping 1 enable function mapping

4 – FMS Function Mapping Select – Selects if a Function Mapping Code (see Table 3.46)

or an av_operation_id (see Table 3.20) is set in GPIO conguration register [8:15]. Valid only if FME=1. 0 select Function Mapping Code (Table 3.46) 1 select av_operation_id (Table 3.20)

[5:7] Reserved

[8:15]

function mapping code / av_operation_id

A Function Mapping Code (FMC, Table 3.46) or an av_operation_id (Table 3.20) is set in this bit eld. The pin is mapped to a prole specic function (A2DP,HFP) or

to an AVRCP remote control operation and will carry out the assigned operation. A mapped function does not affect any other ag of the GPIO conguration register. So, e.g. DIR and INV must be set manually according to the selected function and hardware requirements. Valid only if FME=1. FMS selects function mapping code or av_operation_id.

See also section 6.1, on page 80 “Prole specic GPIO function mapping” And section 5.5 on page 53 “AVRCP GPIO Mapping”

Table 3.44: GPIO Conguration Register Field Descriptions

Handshaking Wi-Fi Coexistence

GPIO - Alternative Functions

Figure 3.29: GPIO conguration register

Alternative Function

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S650 0 0..1 Mode for GPIO Cong Registers:

0 = no mask; 1 = enable i/o pin state mask

S651 GPIO1 0x0000 0..0xFFFF GPIO Conguration Registers

S652 GPIO2

S653 GPIO3

S654 GPIO4

S655 GPIO5

S656 GPIO6

S657 GPIO7

S658 GPIO8

S670 GPIO1..8 0x0000 0..0xFF Read/Write all GPIOs in one atomic step

Table 3.45: GPIO S Registers

S650 must be set to 0 to enable conguration access Controls Pin State, Pin Direction, Pin Inversion, Function Mapping Enable, Function Mapping Select and Function Mapping Code / av_operation_id.

See Table 3.37: GPIO Conguration

(Write operation only affects GPIOs congured as outputs) 0x0001: GPIO1 0x0002: GPIO2 0x0004: GPIO3 0x0008: GPIO4 0x0010: GPIO5 0x0020: GPIO6 0x0040: GPIO7 0x0080: GPIO8

  6.1 ProleSpecicGPIOFunctionMapping

In some Bluetooth proles it makes sense to map GPIOs to certain functions, e.g., Volume Up/Down (HFP/A2DP), answer call (HFP), reject call (HFP) etc. Therefore, new S registers 651 to 663 will be

introduced, corresponding to GPIO1 to GPIO13. If a function mapping code is set to one of those registers and function mapping enabled (FME=1), the appropriate Pin will carry out the assigned function and will not be available anymore as GPIO.

The logical level of a GPIO can be inverted by setting the appropriate INV-ag of the appropriate GPIO Conguration Register.

Restrictions can apply if certain GPIOS will be reserved for other functions in future, e.g., Wi-Fi coexistence signalling.

Function Mapping Code Value Comment

Volume Up 0x01 A2DP,HFP: adjust volume locally

Volume Down 0x02 A2DP,HFP: adjust volume locally

Mute 0x03 A2DP,HFP

Answer Incoming Call 0x04 HFP

Reject Call or Hang Up 0x05 HFP

Reject Call 0x06 HFP

Hang Up 0x07 HFP

Table 3.46: GPIO Function Mapping Codes

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Miscellaneous

1. SCO / eSCO Audio Link

BTM modules provide an AT command to establish an SCO/eSCO audio connection between a pair of

BTM modules (or BISM2). This enables the user to create bidirectional audio links independently from a particular Bluetooth prole. The only prerequisite is the existence of a Rfcomm link (serial port prole)

between the modules. If this link doesn’t exist, it can be created using AT+SPD<BdAddr>. Please refer to section 2 on page 29.

A SCO/eSCO link is intended for bidirectional transmission of speech. The sampling rate is xed to 8 kHz, meaning a usable bandwidth of 3.5 kHz.

For SCO there are three packet types dened in the Bluetooth specication [1]: HV1, HV2, HV3. Each of them occupies one slot. They differ in the level of bit error checking. It is recommended to enable all three packet types for SCO links. This will pass the nal decision down to the baseband. There is no retransmission of erroneous SCO packets.

For eSCO and basic data rate, there are three packet types dened in the Bluetooth specication [1]: EV3, EV4, EV5. EV3 occupies one slot, EV4 and EV5 can occupy up to three slots each. They differ in the level of bit error checking. It is recommended to enable all three packet types for eSCO links. This will pass the nal decision down to the baseband. eSCO packets involve a CRC code and retransmission of erroneous eSCO packets.

Packet types and link types (SCO or eSCO) are negotiated on link setup. A BTM can accept either incoming SCO or eSCO links (S register 584), but not both SCO and eSCO at one time. If the

initiating side requests an unsupported link type, the audio link will fail. The initiating BTM module is supposed to request the remaining link type in that case.

Table 3.58 lists all AT commands and S-Registers for SCO/eSCO links.

Task AT-Command/S-Register Comment

Initiate SCO link AT+BTAx x = packet type bitmask, recommended value = 7

1 = HV1 2 = HV2 4 = HV3

Initiate eSCO link AT+BTA100x x = packet type bitmask, recommended value = 7

1 = EV3 2 = EV4 4 = EV5

Release SCO/eSCO link AT+BTA0 / AT+BTA

Initiate SCO/eSCO link AT+BTA8 Link type (SCO/eSCO) and packet types dened by

S584.

Enable either SCO or eSCO for incoming requests and for AT+BTA8

Initiate SCO/eSCO link automatically on each SPP link

S584 [0..1] 0 = SCO (HV1,HV2,HV3) enabled

1 = eSCO (EV3,EV4,EV5) enabled

Only one link type can be enabled at one time.

S532 [0..7] The recommended value to enable this feature is

7. Value = bitmask for packet type. The link type (SCO/eSCO) is dened by S584. 0 : feature disabled 1 : HV1 (S584=0) or EV3 (S584=1) 2 : HV2 (S584=0) or EV4 (S584=1) 4 : HV3 (S584=0) or EV5 (S584=1)

Table 3.58: SCO/eSCO AT-commands and S-Registers

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1.1 SCO / eSCO Asynchronous Messages

The following asynchronous messages apply to SCO/eSCO connections.

AUDIO ON (SCO)

This response is sent to the host when a SCO channel has been established.

AUDIO ON (eSCO)

This response is sent to the host when a eSCO channel has been established.

AUDIO OFF

This response is sent to the host when an existing SCO/eSCO channel has been closed.

AUDIO FAIL

This response is sent to the host when a SCO channel setup fails. This might be caused by the fact that the peer only accepts eSCO connections but a SCO connection was requested or vice versa. Please try to initiate the SCO connection with the remaining link type.

2. Link Key Management

On a BTM device, link keys are managed by the AT rmware. Appropriate AT commands are described in on page 24. There is a range of S Registers dening the behavior of automatic link key storage on

incoming/outgoing and dedicated/general bonding.

2.1 Dedicated Bonding

In BT2.1 specication, “dedicated bonding” is dened as the exchange of link keys between two devices without the intention of establishing a connection immediately.

Dedicated bonding is initiated by “AT+BTW<BdAddr>” (initiation of pairing).

2.2 General Bonding

In BT2.1 specication, “general bonding” is dened as the exchange of link keys between two devices with the intention of establishing a connection immediately. This is the case if a device

tries to connect to another device without existing link key. Hence, pairing (authentication and exchange of link keys) is initiated automatically prior to the connection.

General bonding is initiated by a connection requesting AT command if there is no link key for

the peer device existing. Such AT commands are:

“AT+SPD<BdAddr>”, “AT+APD<BdAddr>”, “AT+AVD<BdAddr>”, ”AT+HSD<BdAddr>”, “AT+HSGD<BdAddr>”, “AT+HFD<BdAddr>”, “AT+HFGD<BdAddr>”, “AT+DUD<BdAddr>”

2.3 Automatic storage of link keys

Four S Registers dene the automatic storage of link keys in the trusted device list, depending on incoming/outgoing and general/dedicated bonding. Please see Table 3.59.

Task S-Register Comment

Automatic link key storage on dedicated bonding outgoing

(DBO)

Automatic link key storage on

general bonding outgoing (GBO)

Automatic link key storage on dedicated bonding incoming

(DBI)

Automatic link key storage on

general bonding incoming (GBI)

Table 3.59: Automatic storage of link keys

S325 [0..1] 0 = do not store (cache only)

1 = store automatically (default)

identical with S538

S326 [0..1] 0 = do not store (cache only)

1 = store automatically (default)

S327 [0..1] 0 = do not store (cache only)

1 = store automatically (default)

S328 [0..1] 0 = do not store (cache only)

1 = store automatically (default)

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 3. ProleConnectionStatus

The connection status of a prole can be queried by an ATI-Command. This might be helpful in order to decide whether to disconnect all connected proles (via ATH*) or a certain one. For details please

see Table 3.60.

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Task AT-Command Comment

Get connection status of SPP

Get connection status of A2DP

Get connection status of AVRCP

Get connection status of HSP-Headset

Get connection status of HSP-AG

Get connection status of HFP-HF

Get connection status of HFP-AG

Get connection status of DUN

ATI60 0 = not connected

1 = connected (local command mode) 2 = connected (remote command mode)

identical with ATI9

ATI61 0 = not connected

1 = connected

ATI62 0 = not connected

1 = connected

ATI63 0 = not connected

1 = ACL connected 2 = audio connected

ATI64 0 = not connected

1 = ACL connected 2 = audio connected

ATI65 0 = not connected

1 = SLC connected 2 = audio connected 3 = in call, SLC 4 = in call, audio

ATI66 0 = not connected

1 = SLC connected 2 = Audio connected 3 = in call - SLC 4 = in call – audio

ATI67 0 = not connected

1 = connected

Table 3.60: Prole connection status

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 4. DisconnectingProles

A connection to a prole can be released by “ATH<Prole-UUID>”. For A2DP and AVRCP this means a second way of disconnecting.

The response on a disconnect command is usually “NO CARRIER <proleUUID>” if a connection has existed and S329=0. If no connection has existed and S329=0, no proleUUID is appended.

If all connections are to be released, ATH* may be used. Please see Table 3.61.

Task AT-Command Comment

Disconnect SPP ATH1101 or

AT+SPH or ATH

Disconnect A2DP ATH110D or

AT+APH

Disconnect AVRCP

Disconnect HSG ATH1112 or

Disconnect HS ATH1108 or

Disconnect HFG ATH111F or

Disconnect HF ATH111E or

Disconnect all

proles listed in

this table

ATH110E or AT+AVH

AT+HSGH

AT+HSH

AT+HFGH

AT+HFH

ATH* Response:

Single “ATH” retained for backward compatibility, response “NO CARRIER” or ”NO CARRIER 1101” depending on S329 and if a SPP connection has existed

previously

If A2DP connection released: response = “NO CARRIER 110D”; If no A2DP connection has existed: response = “NO CARRIER”

If AVRCP connection released: response = “NO CARRIER 110E”; If no AVRCP connection has existed: response = “NO CARRIER”

If AG(HSP) connection released: response = “NO CARRIER 1112”; If no HSP connection has existed: response = “NO CARRIER”

Must be enabled by S332 because it would result in a behaviour not dened in HSP specication. If HS(HSP) connection released: response = “NO CARRIER 1108”; If no HSP connection has existed: response = “NO CARRIER”

If AG(HFP) connection released: response = “NO CARRIER 111F”; If no HSP connection has existed: response = “NO CARRIER”

If HF(HFP) connection released: response = “NO CARRIER 111E”; If no HSP connection has existed: response = “NO CARRIER”

“NO CARRIER <ProleUUID>” for each previously connected prole or “NO CARRIER” if no existing connection found or HS connected but S332=0

Table 3.61: Prole release commands

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5. Legacy Response Format (BISM2)

Some BISM2 responses have been slightly changed on BTM modules in order to provide enhanced functionality. If required, a BISM2 compatible response format can be enabled by S Register 329. Table 3.63 shows the implications of enabled/disabled legacy response format.

Task S-Register Comment

Enable legacy response format

(BISM2 compatible)

Table 3.62: Enabling/Disabling legacy response format

Command Legacy response format

“AT+SPH”;”ATH1101” Response = “NO CARRIER” If SPP was connected, response =

“AT+APH”;”ATH110D” Response = “NO CARRIER” If A2DP was connected, response

“AT+AVH”;”ATH110E” Response = “NO CARRIER” If AVRCP was connected, re-

“AT+HSH”;”ATH1108” Response = “NO CARRIER” If HS instance was connected,

“AT+HSGH”;”ATH1112” Response = “NO CARRIER” If HSG instance was connected,

“AT+HFH”;”ATH111E” Response = “NO CARRIER” If HF instance was connected,

“AT+HFGH”;”ATH111F” Response = “NO CARRIER” If HFG instance was connected,

“AT+DUH”;”ATH1103” Response = “NO CARRIER” If DUN was connected, response

S329 [0..1] 0 = disabled (default)

1 = enabled

enabled (S329=1)

Table 3.63: Implications of S329

Legacy response format disabled

(S329=0)

“NO CARRIER 1101”

If SPP was not connected, re-

sponse = “NO CARRIER”

= “NO CARRIER 110D”

If A2DP was not connected,

response = “NO CARRIER”

sponse = “NO CARRIER 110E”

If AVRCP was not connected,

response = “NO CARRIER”

response = “NO CARRIER 110E”

If HS instance was not connected,

response = “NO CARRIER”

response = “NO CARRIER 1112”

If HSG instance was not connect-

ed, response = “NO CARRIER”

response = “NO CARRIER 111E”

If HF instance was not connected,

response = “NO CARRIER”

response = “NO CARRIER 111F”

If HFG instance was not connect-

ed, response = “NO CARRIER”

= “NO CARRIER 1103”

If DUN was not connected, re-

sponse = “NO CARRIER”

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6. UUIDs in “CONNECT”/”NO CARRIER” Messages

In proles where functionality and command set differs between both possible roles (asynchronous proles), role indicating UUIDs are used in the “CONNECT” and “NO CARRIER” messages. HSP and HFP are asynchronous proles.

A2DP and AVRCP are treated as synchronous proles because only one prole instance with one role selected can be initialised currently. Therefore, a common UUID is used indicating the prole only, but

not the role.

In a message “CONNECT <bd_addrhex>,<UUID>”, UUID is the prole/role the connection is made to. Hence for an outgoing connection, UUID indicates the remote device’s prole/role. If it is an incoming connection, UUID indicates the local device’s prole/role UUID. Hence, role indicating UUIDs presented in a “CONNECT” message will be equal on both ends of a connected pair.

In a message “NO CARRIER <UUID>”, UUID represents the local prole/role UUID. Hence for an asynchronous prole, role-indicating UUIDs will differ on both ends of a previously connected pair.

Table 3.64 Gives an overview of currently used UUIDs on BTM devices.

UUID (hex) Prole/Role Role indication Comment

1101 SPP No Synchronous prole

1108 HSP – HS Yes Headset role (Headset prole)

110D A2DP No Common UUID for source and sink role

110E AVRCP No Common UUID for controller and target role

1112 HSP – AG Yes Audio gateway role (Headset prole)

111E HFP – HF Yes Hands-free role (Hands-free prole)

111F HFP – AG Yes Audio gateway role (Hands-free prole)

Table 3.64: UUIDs used in BTM5xx CONNECT/NO CARRIER messages

There is an option to append a direction indicator to a connect message. This enables the host to

distinguish an incoming connection from an outgoing connection based on the “CONNECT“ message. The direction indicator only applies to role indicating UUIDs and if S329=0. The direction indicator is congured by S register 331, please refer to Table 3.65.

S331 Meaning Example

Incoming connection Outgoing connection

0 Disabled CONNECT

0123456789AB,1108

1 Character style, ‘I’ or ‘O’ CONNECT

0123456789AB,1108,I

2 (default) Symbol style, ‘<’ or ‘>’ CONNECT

0123456789AB,1108,<

Table 3.65: Examples for direction indication in “CONNECT” messages

7. Page Scan / Inquiry Scan Interval and Window

Page scanning means being connectable. Inquiry scanning means being discoverable. With the following S registers the power consumption of the BTM can be inuenced. However, lower power consumption means longer connection establishment time and longer time until a BTM is discovered by other devices.

The page scan window denes the time for the module to look out for incoming connection requests (paging). The inquiry scan window denes the time for the module to look out for incoming inquiry requests (device discovery). If the module is both connectable and discoverable (512=4 or AT+BTP issued), it will mutually do page scanning and inquiry scanning as shown in Figure 3.33. If connectable only, the module will perform page scanning only (repeatedly) and if discoverable only, then the module

will perform page scanning only.

S register 508 denes the page scan interval in ms, range is [11..2250].

S register 509 denes the page scan window in ms, range is [11..2250].

S register 510 denes the inquiry scan interval in ms, range is [11..2250].

S register 511 denes the inquiry scan window in ms, range is [11..2250].

CONNECT 0123456789AB,1108

CONNECT 0123456789AB,1108,O

CONNECT 0123456789AB,1108,>

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Figure 3.33: Page and Inquiry Scan Intervals and Windows

8. Sniff Mode

Bluetooth connections are master/slave in nature. A master sends packets and a slave has to acknowledge that packet in the next timeslot. Timeslots in Bluetooth are 625 microseconds wide. This implies that a master will always know when packets will be sent and received, which further means it is able to optimise power usage by switching on power hungry circuitry only when needed.

A slave on the other hand does NOT have prior knowledge of when a packet will be received and has to assume that a packet will be received from a master on every receive slot. This means that it has to leave its receiving circuitry on for most of the receive slot duration. The result of this is high power

consumption on slave side. In general, a slave draws about ve times the current of a master. This problem was identied very early in the evolution of Bluetooth (especially since headsets spend all their time as a slave in a Bluetooth connection) and was solved by having a mode called Sniff;

with appropriate lower layer negotiating protocol.

Sniff mode during connection is basically an agreement between the slave and its master that data packets will only be exchanged for N timeslots every M slots. The slave can then assume that it will

never be contacted during M-N slots, and so can switch its power hungry circuitry off. The specication goes further by also specifying a third parameter called ‘timeout’ (T) which species ‘extra’ timeslots

that the slave will agree to listen for after receiving a valid data packet. Put another way, if a data packet is received by the slave, then it knows that it MUST carry on listening for at least T more slots. If within that T slot time period another data packet is received, then the timer is restarted. This mechanism ensures low power consumption when there is no data transfer – at the expense of latency. When there is a lot of data to be transferred, it acts as if sniff mode were not enabled.

It is stated above that during sniff mode, a slave listens for N slots every M slots. The Bluetooth specication states that a master can have up to seven slaves attached to it with all slaves having requested varying sniff parameters. It may therefore be impossible to guarantee that each slave gets the M parameter it requested. In light of this, the protocol for enabling sniff mode species that a requesting peer specify the M parameter as a minimum and maximum value. This will allow the master to interleave the sniff modes for all slaves attached.

For this reason, the sniff parameters are specied in the BTM module via four S registers. S Register 561 is used to specify ‘N’, S Register 562 is used to specify ‘T’ and S Registers 563/564 are used to

specify minimum ‘M’ and maximum ‘M’ respectively. Although the specication denes these parameters in terms of timeslots, the S register values have to be specied in units of milliseconds and the rmware does the necessary translation to timeslots.

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Figure 3.34: Sniff Mode Example

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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)

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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.

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Figure 3.35: BREAK capability in Ezurio Terminal

16. Append Bluetooth Address to Friendly Name

If S Reg 593 is set to 1, then the last six hex digits of the Bluetooth address are automatically appended to the friendly name. This allows multiple devices with the same name in a neighborhood to be differentiated.

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Appendix

General S Registers

The following table lists all general S Registers. Please not that this is not a complete listing of S Registers.

Additional S registers, associated with a certain prole or feature are described in the appropriate section above.

S2 94 32..126 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 ‘^’.

S12 100 40..5000 Escape sequence guard time in milliseconds, with a granularity of

20ms. New values are rounded down to the nearest 20ms multiple

S101 $1101 $0..$ffff UUID of default SPP based prole when not specied explicitly in

the ATD command.

S102 Depending

on module variant

S103 1 1..4 Boot Mode on cold boot

S325 1 0..1 Store link key automatically on dedicated bonding outgoing (DBO)

S326 1 0..1 Store link key automatically on general bonding outgoing (GBO)

S327 1 0..1 Store link key automatically on dedicated bonding incoming (DBI)

S328 1 0..1 Store link key automatically on general bonding incoming (GBI)

S329 0 0..1 Enable legacy (BISM2) response format

S330 1 1..31 Congure inquiry response of AT+BTI (Bitmask):

S331 2 0..2 Direction indication style for “CONNECT” messages

Depending on supported

proles

Denes a set of bits masks for enabling proles. Values can be

ORed.

A prole can be enabled only if it is supported by the BTM variant. Issue AT&W and ATZ in order to make the new setting effective. 0x001 is Serial Port Prole 0x002 is Headset (“HS”)

0x004 is DUN

0x008 is Audio Gateway (Headset, ”HSG”) 0x010 is Handsfree (“HF”)

0x020 is OBEX FTP

0x040 is Audio Gateway (Handsfree, “HFG”)

0x080 is A2DP 0x100 is AVRCP 0x200 is PBAP 0x400 is HID

2..4 – for future customization of the module

1 - show device address 2 - show class of device 4 - show friendly name 8 - show extended inquiry data Values can be ORed

0 – disabled 1 – character style: append ‘I’ to incoming and ‘O’ to outgoing

CONNECT message, separated by a comma

2 – symbol style: append ‘<’ to incoming and ‘>’ to outgoing

CONNECT message, separated by a comma

applies only to role indicating UUID (e.g.HSP/HFP) and if S329=0

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S334 0 0..1 Enable Extended Sdp Error Codes

0 - disable

1 – enable

S504 0 0..1 Enable silent operation:

Setting to 1 will force S0 to -1 and will suppress messages arising from connections or pairing. E.g., CONNECT, NO CARRIER, RING, PAIR, etc. Suppressing connection based messaged allows the device to be

congured in cable replacement mode.

S505 10 2..120 Minimum delay before abandoning connection attempt as a

master. Referenced by ATD. In units of seconds. See S Registers 530 and 543 also. Please note that as disconnection time can vary, this register only guarantees the minimum delay. Note that for invalid

addresses specied in the ATD command, the “NO CARRIER”

response will be immediate. See S register 560 for specifying disconnect max timeout.

S506 0 0..1 Enable/Disable echoes. The ATEn command also affects this.

S507 0 0..2 When set to 0, a connection can be dropped using ^^^ escape

sequence only and the state of DSR line is ignored. When set to 1, a connection can be dropped using EITHER the

^^^ escape sequence OR the DSR handshaking line. When set

to 2, a connection can only dropped using a deassertion of DSR. Mode 2 provides for the highest data transfer rate. If the status of the DSR line is to be conveyed to the remote device as a low bandwidth signal then this register MUST be set to 0, otherwise a deassertion of DSR will be seen as a request to drop

the Bluetooth connection. This register affects S Register 536 – see

details of 536.

S508 640 11..2550 Page Scan Interval in milliseconds. Minimum is 11.25ms so

10/11ms will give 11.25ms, refer to Section 7, page. 85.

S509 160 11..2550 Page Scan Window in milliseconds. Minimum is 11.25ms so

10/11ms will give 11.25ms, refer to Section 7, page. 85.

S510 640 11..2550 Inquiry Scan Interval in milliseconds. Minimum is 11.25ms so

10/11ms will give 11.25ms, refer to Section 7, page. 85.

S511 160 11..2550 Inquiry Scan Window in milliseconds. Minimum is 11.25ms so

10/11ms will give 11.25ms, refer to Section 7, page. 85.

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S512 1 0..7 Specify power up state.

When set to 0, AT+BTO is required to open the device for Bluetooth activity. When set to 1, it proceeds to a state as if AT+BTO was entered. When set to 2, it will be discoverable only, similar to issuing AT+BTQ. When set to 3, it will be connectable but not discoverable e.g. AT+BTG When set to 4, it will be connectable and discoverable e.g. AT+BTP.

When set to 5, it will be like 2, but all UART RX trafc is discarded

in absence of a connection while DSR is asserted. If DSR is not asserted, then it behaves exactly as per mode 2.

When set to 6, it will be like 3, but all UART RX trafc is discarded

in absence of a connection while DSR is asserted. If DSR is not asserted, then it behaves exactly as per mode 3.

When set to 7, it will be like 4, but all UART RX trafc is discarded

in absence of a connection while DSR is asserted. If DSR is not asserted, then it behaves exactly as per mode 4. Note that by implication, a change to this can only be seen after a

power cycle AND if AT&W is

S514 10 1..60 Pairing Timeout in seconds. This includes the time a host takes to

supply the PIN number when PIN? Messages are indicated.

S515 $001F00 $000000..

$FFFFFF

S516 $000000 0.. $2FFFFFF Default Device Class lter to be used with AT+BTI when it is not

S517 20 2..61 Inquiry Length in units of seconds. This parameter is referenced by

S518 8 0..255 Maximum number of responses from an inquiry request. This

S519 500 100..3000 When S507>0, and in a connection, DSR can be used to change

Default Device Class Code. When queried, the value is always printed as a hexadecimal number. To change the device class of the module temporary and immediately without power cycle, use the command AT+BTC. To change the device class of the module permanently, write the

new value to this S Register (ATS515=$<devclass ting (AT&W) and initiate a power cycle (ATZ).

explicitly specied. When queried the value is always printed as a

hex number.

The seventh most signicant digit, can be 0,1 or 2, and is used to specify the type of device class lter. When 0, it species no ltering. When 1, it species an AND mask and all 24 bits are relevant When 2, it species a lter to look for devices with matching major device class which occupies a 5 bit eld from bits 8 to 12 inclusive (assuming numbering starts at bit 0). All other 19 bits MUST be set

to 0.

the AT+BTI command.

parameter is reference by the AT+BTI command. If this number is set too high, then AT+BTI will return ERROR 27. For a particular

rmware revision, determine the effective maximum value by trial

and error. That is, set to a high value, send AT+BTI and if ERROR 27 is returned, then retry with a smaller value. This effective max value will remain unchanged for that particular

rmware build.

from data to command state by de-asserting the DSR line for less

than the time specied in this register. This value is rounded down

to the nearest 100ms

>), save the set-

hex

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S520 9600 1200..

..115200

S521 9521 1200..

..921600

S523 1 1..2 Number of Stop bits

S524 0 0..2 Parity. 0=None, 1=Odd, 2=Even

S525 0 0..1 Apply multiplier of 8 to baud rate internally. This is set to 0

S526 3 1..3 This register species a 2 bit mask used to qualify how S Registers

S530 1000 100..15000 Reconnect delay when congured as master in pure-cable-replace-

Change to a standard baud rate. The effect is immediate and in fact the OK will be sent at the new baud rate. Only one of the

following baud rates are accepted: 1200,2400,4800,9600,19200,

28800,38400,57600,115200.

If S register 525=1, then the maximum baud rate is limited to

115200.

Change baud rate to non-standard value. BTM modules support any baud rate. The only limitation is the integer arithmetic involved, which may adjust the applied rate slightly. If the internally

computed baud rate is more than 2% offset from the desired

input value, then an ERROR will be returned and the old baud rate will prevail. To inspect the actual baud rate, do ATS521? S521 should only be sued for non-standard baud rates. For standard baud rates use S520. The effect is immediate and in fact the OK will be sent at the new baud rate.

If S Register 525=1, then the max baud rate is limited to 115200

In the event that a non-standard baud rate is requested, it is entirely possible that the host is not capable of generating such a baud rate. In this case the BTM device cannot be communicated with. If this happens, there is a procedure to recover from

this situation which is described in section 13, page. 87 “Factory Default UART Baud Rate”.

See S Register 526 for further information.

For the Go blue Activator variant of the module this register is read only. See S Register 526 for further information.

(disabled) by default. If S Register 521 > 115200 then this register cannot be set to 1. See S Register 526 for further information.

520 to 525 are actioned. If bit 0 is 1, the new communication parameters affect the UART immediately. If bit 1 is 1, the new communication parameters are stored in non-volatile memory So for example, to change communication parameters, but have them come into effect only after subsequent power cycles, then this register should be set to 2, and likewise to affect immediately and yet not have it persist over a power cycle, the value should be set to 1. Must be set before the baud rate change.

ment mode. This value is rounded down to the nearest 100ms. See S Register 505 also.

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S531 0 0..4 Species the mode on connection establishment.

0 = Normal, that data is exchanged between UART and RF. 1 = LOCAL_COMMAND. UART input is parsed by the AT

interpreter and RF data is discarded.

2 = REMOTE_COMMAND. RF input is parsed by the AT interpreter

and UART data is discarded. If S Register 536 is not 1 then this register cannot be set to 2 and an ERROR will be returned. 3 = LOCAL_COMMAND. UART input is parsed by the AT interpreter and incoming RF data is sent to the host using the RX<string> asynchronous response.

4 = LOCAL_COMMAND and on the rf side, the GPIO is automatically sent when there is a change in input. (digital I/O cable replacement mode).

S532 0 0..7 If non zero then on every connection, a SCO channel (audio) will

be initiated. Bit 0 for HV1, Bit1 for HV2 and Bit2 for HV3. When the connection is lost, the SCO channel disappears along with it.

S535 20 0..41 Link Supervision Timeout. If units go out of range, then a NO CAR-

RIER message will be sent to the host after the time specied here.

S536 0 0..1 When set to 1, a remote device can ‘capture’ the AT parser of this

unit by it sending this module an escape “!!!” sequence. The inter

character timing is set via S Register 12.

If S Register 507 is >= 2, then reading this register will always

return 0 and writing 1 will result in ERROR 33.

S539 0 0..1 When set to 1, in idle mode (S512=1), UART Rx characters are

discarded if DSR is de-asserted.

S541 20 -43..20 This sets the power level in dBm when inquiring or paging. Read-

ing this register returns the value stored in non-volatile memory.

S542 4 -43..20 As per S541, however reading this register returns the current

power level as set in the base band. The read can be different from S541because the actual power is set using a lookup table and the base band rounds down to the nearest value in the table.

S551 $3211 $0..$ffff This register species in each 4 bit nibble, how the outgoing

modem status bits to the remote peer gets its value. Bluetooth® allows for RTR, RTC, DV and IC bits to be exchanged over an RFCOMM connection.

Nibble 0..3 species the source for RTC

4..7 species the source for RTR

8..11 species the source for DV (i.e., DCD)

12..15 species the source for IC (i.e., RI) Each nibble can take the following value:

0 Always set to 0 1 Always set to 1

2 If DCD (pin 8 on module connector) is output then always 1

If DCD is input then 1 if DCD is asserted otherwise 0

3 If RI (pin 6) is output then always 0

If RI is input then 1 if RI is asserted otherwise 0

4 If DSR (pin 10) is asserted then 1 otherwise 0 In the event that a nibble species DSR as the source of its state,

be aware that if, S Register 507 is anything other than 0, a de-assertion of DSR will cause the Bluetooth connection to be dropped. If bits 0..3 and 4..7 are set to 0, then some Bluetooth devices will use that as a signal to stop sending any data back.

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S552 $0122 $0..$fff This register species in each 4 bit nibble, how the DTR, DCD, RI

output pins are controlled when in a Bluetooth connection

Nibble 0..3 species the source for DTR

4..7 species the source for DCD

8..11 species the source for RI Each nibble can take the following value:

0 Do NOT touch the I/O 1 Always deassert 2 Always assert 3 If RTC bit in CONTROL_IND is 1 then assert otherwise deassert 4 If RTR bit in CONTROL_IND is 1 then assert otherwise deassert 5 If DV bit in CONTROL_IND is 1 then assert otherwise deassert 6 If IC bit in CONTROL_IND is 1 then assert otherwise deassert If this register is changed while in command and connected mode, then on going back online using the ATO command, the modem output lines will get refreshed.

S553 $0201 $0..$fff This register species in each 4 bit nibble, how the DTR,DCD,RI

output pins are controlled when NOT in a Bluetooth connection

Nibble 0..3 species the source for DTR

4..7 species the source for DCD

8..11 species the source for RI

In addition it also refers to S Register 552 to see if the relevant pin is an input or not to be touched. If the nibble in 552 is 0, then the relevant pin is an input.

Each nibble can take the following value:

0 Always deassert 1 Always assert 2 Assert if RING is being sent to the host

S554 0 0..900 Post Reset Window: If S Register 512>=2 and <=7 then this regis-

ter species a time in seconds for which the device will stay in the

S512 mode after power up or reset. On timeout, it will abort the

discoverable and/or connectable and fall back into S512=1 mode, when it is deaf and dumb. (not connectable, not discoverable)

Note that if AT+BTR has been used to specify a peer device, then on reverting to mode 1, it will attempt to make a connection to that peer device. A power cycle, reset via BREAK or ATZ is required to see the effects of change.

S555 1 1..7 If S Register 554 is nonzero, then after the post reset (dened by

S554) window expires, the mode will revert to the mode specied in

this register. This allows, for example, the device to be discoverable

and connectable on power up (mode 4 or 7) and on window timer expiry to revert to connectable only (mode 3 or 6).

A power cycle, reset via BREAK or ATZ is required to see effects of

a change. In some rmware builds, S Registers 565 to 569 inclusive

are visible, which allows the start-up mode to depend on the state

of RI line (Setting S Reg 565 forces the RI pin to be congured as an input). For this feature to be active, S Reg 565 should be set to 1.

In that case, on start-up, if RI is asserted, then the start-up mode is

dened by S Reg 568 and if de-asserted then S Reg 569.

S558 0 0..1 When 1, the following responses; “RING”, “NO CARRIER” and

“CONNECT” are replaced by “BTIN”, “BTDOWN” and “BTUP”

respectively. This will eliminate ambiguity when the module has a Bluetooth connection to an AT modem which also gives these responses.

S559 0 0..3 This species a mask. When Bit 0 is 1, the response word “ERROR“

is replaced by “BTERR” and “OK” is replaced by “ok”.

When Bit 1 is 1, then error responses do not include the error number and instead the error number can be retrieved using ATI12.

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S560 15 15..120 Disconnect timeout in seconds. This timer species how long to

wait for conrmation from the peer device and/or the underlying

stack that the connection has been successfully torn down. There

can be instances where a conrmation does not arrive and so in

this case this timer is used to ‘close off’ the procedure and put the state machine back into a proper mode for new operations.

Time is specied with 15 seconds intervals.

S561 0 0..1000 Sniff Attempt Time in units of milliseconds. 0 means disable.

See Section 8, page 86 and Figure 3.34.

S562 0 0..1000 Sniff Timeout Time in units of milliseconds. 0 means disable.

See Section 8, page 86 and Figure 3.34.

S563 0 0..1000 Sniff Minimum Interval in units of milliseconds. 0 means disable.

See Section 8, page 86 and Figure 3.34.

S564 0 0..1000 Sniff Maximum Interval in units of milliseconds. 0 means disable.

See Section 8, page 86 and Figure 3.34.

S565 0 0..1 If set to 1, RI (Ring Indicate) line is congured as an input and

forces the start-up mode (S Reg 512) and post-timeout on Start-up mode (S Reg 555) to be dependent on the state of RI. The RI conditional modes are dened by S Registers 566 to 569 inclusive.

S566 1 1..7 If S565=1, and RI is asserted then this is the mode the device will

start up in.

S567 1 1..7 If S565=1, and RI is de-asserted then this is the mode the device

will start up in.

S568 1 1..7 If S565=1, and RI is asserted then this is the mode the device

will assume after the post-start-up timeout dened in S Reg 554 instead of mode dened in S Reg 555.

S569 1 1..7 If S565=1, and RI is de-asserted then this is the mode the device

will assume after the post-start-up timeout dened in S Reg 554 instead of mode dened in S Reg 555.

S584 0 0..1 Enable/Disable eSCO.

S588 0 0..1 After a disconnection, there will be a cold reset.

S592 0 0..1 Set this to 1 to reduce the trusted device database to just 1 record

when auto saving of pairing is enabled via S reg 538.

S593 0 0..1 Automatically append last six digits of local Bluetooth address to

the Friendly name which was set via AT+BTN or AT+BTF.

S1001 to S1010

0 0..2^32 10 General Purpose 32 bit Registers for use by host. These are

stored in non-volatile memory.

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Table 4.1: BTM - General S Registers

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ATI Commands

The following table lists all ATIn parameters supported by a BTM device. ATI commands provide general information about the BTM device and status information.

Commands Information

ATI0 The product name/variant.

ATI1 The CSR rmware build number.

ATI2 The AT rmware build number. For internal use only.

ATI3 The AT rmware revision.

ATI4 A 12 digit hexadecimal number corresponding to the Bluetooth address of the BTM device.

ATI5 The manufacturer of this device.

ATI6 The maximum size of trusted device database.

ATI7 The manufacturer of the Bluetooth chipset.

ATI8 The chipset format.

ATI9 SPP connection status:

0=not connected 1=connected in local command mode 2=connected in remote command mode

ATI11 The reason why a “NO CARRIER” resulted in the most recent attempt at making an outgoing

connection. Where the response values are as follows: 0 = No prior connection 1 = Connection timeout 2 = Connection attempt cancelled 3 = Normal disconnection 4 = Peer device has refused connection 5 = Service prole <uuid> requested not available on remote device 6 = Connection has failed 32 = ATH was entered 33 = Incoming connection aborted because too many rings 34 = Unexpected incoming connection 35 = Invalid address 36 = DSR is not asserted 37 = Call limit of 65531 connections has been reached 38 = Pairing in progress 39 = No link key 40 = Invalid link key 255 = Unknown Reason

ATI12 The last ERROR response number.

ATI13 The Sniff status is returned as follows:-

Response: <cr,lf>a:b,c,d,e<cr,lf>OK<cr,lf> Where ‘a’ = 0 when not online and 1 when online and Sniff has been enabled, ‘b’ is the Sniff

Attempt parameter, ‘c’ is the Sniff timeout parameter, ‘d’ is the minimum sniff interval and ‘e’ is the maximum sniff interval. All parameters ‘b’, ’c’, ’d’ and ‘e’ are given as Bluetooth slots which are 625 microseconds long converted from values of S Registers 561, 562, 563 and 564 respectively.

ATI14 The current boot mode.

ATI15 The maximum length of an AT command, not including the terminating carriage return.

ATI16 Codec Output Maximum Gain Range.

ATI17 Codec Input Maximum Gain Range.

ATI18 Bluetooth version.

ATI19 Audio connection status: 0 = off, 1= on

ATI20 Returns the number of bytes pending to be sent in the rf buffer when a connection is up.

ATI33 Version number of Multipoint application (Note: ATI is provided for compatibility in multipoint

mode, other AT commands are not available).

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Commands Information

ATI42 State information. Where the response values are as follows:

13 = NotOpen 14 = OpenIdle 15 = Ringing 16 = OnlineCommand 172 to 177 = waiting for connectable and/or discoverable where the lowest signicant digit

equates to the value stored in S Register 512 or 555.

Note when n=16, ATI9 will return 1.

ATI60 SPP connection status: 0 = not connected, 1 = connected; identical with ATI9

ATI61 A2DP connection status: 0 = not connected, 1 = connected

ATI62 AVRCP connection status: 0 = not connected, 1 = connected

ATI63 HSP-Headset connection status: 0=not connected,1=ACL connected,2=audio connected

ATI64 HSP-Gateway connection status: 0=not connected,1=ACL connected,2=audio connected

ATI65 HF connection status:

0 = not connected 1 = SLC connected 2 = Audio connected 3 = in call - SLC 4 = in call – audio

ATI67 DUN connection status:

0=not connected 1=connected in local command mode 2=connected in remote command mode

ATI101 The RSSI value in dBm. If a connection does NOT exist then a value of -32786 is returned.

A value of 0 means the RSSI is within the golden range this is quite a large band, therefore RSSI is not always a useful indicator. Use ATI111 instead which returns the bit error rate.

ATI111 Returns LinkQual which in the CSR chipset is dened as BER (bit error rate). This returns a value

which is the number of bits in error out of 1 million. Hence a value of 0 is best, and larger

values are worse. As the value approaches 1000 (BER = 0.1%) it is an indication that the link is

very bad and a large number of Bluetooth packets are being lost.

ATI200 Manufacturing data (e.g., module serial number, manufacturing date).

ATI333 Full AT rmware version number.

Table 4.2: BTM ATI Commands

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Error Responses

Error Description

01 Register not recognized

02 Value for register is out of range

03 Incoming call NOT pending

04 No call to connect to. This error code has meaning for ATO only

05 Syntax Error

06 Empty String

06 Device Class could not be stored

08 Invalid Device Class Code

09 Invalid Bluetooth Address

10 Could not set Service or Friendly name

11 PS Store Write

12 PS Store Read

13 Not Idle

14 Incorrect Mode

15 Already Scanning

16 Pairing is already in progress

17 Not USED

18 Not USED

19 Not USED

20 Not safe to write to Non-volatile Store - Ongoing Bluetooth Connection

21 Link Key Cache is Empty

22 Link Key Database is Full

23 Malloc returned NULL - Resource Issue

24 Remote Address same as Local Address

25 Connection Setup Fail, DSR Not asserted

26 Unauthenticated licence

27 Max Responses (See S Register 518) too high. Memory allocation error

28 The length of Pin in AT+BTK is too long

29 Invalid Ring count specied for S Register 0 or 100. If S0<>0 and S100<>0 then S0 must be < S100

30 ADC Error

31 Analogue Value cannot be read as it is set for output

32 Analogue Value cannot be written as it is set for input

33 S Register Value is invalid

34 Both L and R modier cannot be specied in ATD command

35 Invalid Major Device Class – valid value in range 0x00 to 0x1F inclusive

36 Pairing in progress – Command cannot be actioned – try again later

37 Invalid Sniff parameter specied.

E.g. new Attempt value greater than MinInterval. Solution is to rst increase MinInterval and re-enter

the Attempt value.

38 Get Remote Friendly name Failed

39 Failed to change mode to Multipoint

40 7 Bit mode requires parity to be even or odd

41 Stream Error

42 Stream Pending Error

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Error Description

43 Unknown Audio Gateway Command

44 Busy, try later

45 Command or operation not allowed

46 No A2DP role has been set (see S register 300)

47 No AVRCP role has been set (see S register 301)

48 No AVRCP category has been set (see S register 302)

49 No AVRCP control connection

50 No A2DP or AVRCP connection currently incoming

51 Invalid operation ID (AVRCP)

52 Wrong AVRCP role

53 Command disabled by S-Register 310

54 No manufacturing information available

55 Audio resource error

56 Invalid UUID

57 Maximum gain level reached

58 Minimum gain level reached

59 Prole or role not enabled

60 Prole under construction

61 Unknown Headset command

62 Unknown Hands-free command

63 Incorrect state

64 Unknown DUN command

65 UART resource error

Table 4.3: BTM Error Responses

List of UUIDs

Table 4.4 gives a list of selected UUIDs. For a complete list refer to the “Assigned Numbers – Service Discovery (SDP)” document [3] by the Bluetooth SIG.

UUID Mnemonic / Prole Role

0x1101 Serial Port Prole (SPP) -

0x1102 LAN access using PPP -

0x1103 Dial-up Networking (DUN) -

0x1105 OBEX Object Push -

0x1106 OBEX File Transfer -

0x1108 Headset Prole (HSP) Headset

0x110A A2DP Audio Source

0x110B A2DP Audio Sink

0x110C AVRCP Remote Target

0x110D A2DP -

0x110E AVRCP -

0x110F AVRCP Remote Controller

0x1112 Headset Prole Audio Gateway

0x111E Hands-free Prole (HFP) Hands-free unit

0x111F Hands-free Prole (HFP) Audio Gateway

Table 4.4: Selected UUIDs

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References

[1] “Bluetooth Specication Version 2.1 + EDR [vol3]”, 26 July 2007

http://www.bluetooth.com/Bluetooth/Technology/Building/Specications/

(click on “Core Specication v2.1 + EDR”)

[2] “Advanced Audio Distribution Prole Specication” Rev. V12, 16/04/2007

http://www.bluetooth.com/Bluetooth/Technology/Works/A2DP.htm

(link at bottom of page “Need more? View the Advanced Audio Distribution Prole (A2DP) 1.2”)

[3] “Audio/Video Remote Control Prole” Revision 1.0 22/05/2003

http://www.bluetooth.com/Bluetooth/Technology/Building/Specications/

(click on “Audio/Video Remote Control Prole 1.0”)

http://www.bluetooth.com/Bluetooth/Technology/Works/AVRCP.htm

(alternative, but only revision 1.3 of the AVRCP spec is available, therefore go to link at bottom of page “Need more? View the Audio/Video Remote Control Prole (AVRCP) 1.3”)

[4] “Headset Prole” Revision V12r00, 18/12/2008

http://www.bluetooth.com/Bluetooth/Technology/Works/HSP.htm

(link at the bottom of page “Need more? View the Headset Prole (HSP)”)

[5] “Hands-free Prole 1.5” Revision V10r00, 25/11/2005

http://www.bluetooth.com/Bluetooth/Technology/Works/HFP.htm

(link at the bottom of page “Need more? View the Hands-Free Prole (HFP) 1.5”)

[6] “Dial-Up Networking Prole” Version 1.1

http://www.bluetooth.com/Bluetooth/Technology/Works/DUN.htm

(link at the bottom of page “Need more? View the Dial-up Networking Prole (DUN)”)

[7] “Serial Port Prole“ Specication

http://www.bluetooth.com/Bluetooth/Technology/Works/SPP.htm

(link at the bottom of page “Need more? View the Serial Port Prole (SPP)”)

[8] “Bluetooth Assigned Numbers”

http://www.bluetooth.com/Bluetooth/Technology/Building/Specications/

select “Items per page: ALL”, go to end of page, there click on “Assigned Numbers – Baseband”,

for a complete list of Prole UUIDs: click on “Assigned Numbers – Service Discovery”

[9] Class of Device Generator: this link might be helpful for creating a particular CoD

http://bluetooth-pentest.narod.ru/software/bluetooth_class_of_device-service_generator.html

Caution: this tool allows selection of more than one minor device classes, so make sure that only one minor device class is select and verify the result with [8] anyway.

[10] “Bluecore 5-Multimedia External” Data Sheet, Cambridge Silicon Radio (CSR)

http://www.csrsupport.com (log in or new account required)

[11] “Bluecore 4 External” Data Sheet, Cambridge Silicon Radio (CSR)

http://www.csrsupport.com (log in or new account required)

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