Ezurio’s BISM2 Bluetooth Serial Module is a fully integrated and qualified Class 1 Bluetooth solution
designed for lowest cost of integration and ownership for designers wishing to incorporate Bluetooth
functionality into their products. The module is qualified to Bluetooth Version 2.0.
The BISM2 Module is based on Cambridge Silicon Radio’s BlueCore 04 chipset. The module contain
all of the hardware and firmware for a complete Bluetooth solution, requiring no further components.
The Module has an integrated, high performance antenna which is matched with the Bluetooth RF and
baseband circuitry. The firmware integrated into the BC04 chipset implement the higher layer
Bluetooth protocol stack, up to and including the Generic Access Profile (GAP), Service Discovery
Profile (SDAP), Serial Port Profile (SPP), Dial Up Networking Profile (DUN) and Audio Gateway. A
virtual processor is used within the BC04 to implement an AT command processor. This interfaces to
the host system over a straight forward serial port using an extensive range of AT commands. The AT
command set abstracts the Bluetooth protocol from the host application, saving many months of
programming and integration time. It provides extremely short integration times for data oriented
cable replacement and voice applications. A low cost development system is available for fast
product evaluation and development.
An alternative version of firmware is available that provides programming support for multi-point
applications.
The Module can be configured so that it can be attached to a ‘dumb’ terminal or attached to a PC or
PDA for cable replacement applications.
In addition to the Bluetooth functionality, The BISM2 Module provides access to 8 General I/O lines
and 2 analogue I/O lines. These can be configured to provide connection to simple devices such as
switches or LEDs without requiring any external processing. Both the GPIO and ADC lines can be
accessed either via the wired host UART connection, or remotely over the Bluetooth link.
The BISM2 module is supplied in a small form factor pcb (25mm x 35mm x 10mm), that connects to
a main pcb using a 40 way Hirose connector. The module includes a high sensitivity, high gain
antenna which provides excellent range. Typical open field performance provides ranges of over 250
metres at transmit powers of only 4mW.
Support is provided for low power modes that make the BISM2 particularly applicable to battery
powered installations.
The BISM2 module is Lead-free and is RoHSA compliant and supports an industrial temperature range
of -40°C to +85°C.
1.1 Applications
•
POS Equipment
•
Medical Equipment
•
Telematics
•
Voice Applications
•
Industrial Automation
•
Automotive Applications
Bluetooth is a trademark owned by Bluetooth SIG, Inc., USA, and is licensed to Ezurio Ltd
Serial Interface RS-232 bi-directional for commands and data using AT commands
Serial parameters
Physical size 25 x 35 x 10 mm, 8g
Current consumption
Low power sniff mode 2.5mA typ
Temperature Range Normal operation: -40°C to +85°C
Interface Levels 3.3V
Audio
Profiles
Multipoint 7 slaves
Field upgradeable Over UART
Protocols
GPIO
Lead free Lead-free and RoHS compliant
Default 9600,n,8,1 - Configurable from 9600bps.
Support for DTR, DSR, DCD, RI, RTS, CTS
Less than 36mA during data transfer with a configurable low power
mode
Audio can be transferred over SCO channels through the PCM interface
at 64kbps
Server - SPP (Full), DUN, Audio Gateway, Headset, Handsfree
Client - All RFCOMM based profiles
UART
Single point firmware is controlled and configured using AT
Commands, multipoint firmware uses a simple packet based protocol
and requires a host to enable the module to function effectively.
Single point only allows a point to point connection where as
multipoint allows up to 7 simultaneous connections.
25 UART_RX Receive Data I/P 26 PCM_OUT PCM Data O/P
27 VCC_3V3 3.3V Output (Note 3) 28 N/C
29 VCC_5V 3.6V < VIN < 6.0V 30 GND
31 N/C 32 RESERVED Do not connect
33 GPIO6 I/O for Host 34 RESERVED Do not connect
35 GPIO7 I/O for Host 36 GND
37 GPIO8 I/O for Host 38 GND
39 RESERVED DO NOT CONNECT 40 N/C
Signal Description
No.
Notes:
UART_RX, UART_TX, UART_CTS, UART_RTS, UART_RI, UART_DCD and UART_DSR are all 3.3v level
logic. For example, when RX and TX are idle they will be sitting at 3.3V. Conversely for handshaking
pins CTS, RTS, RI, DCD, DSR a 0v is treated as an assertion.
Pin 6 (UART_RI) is active low. It is normally 3.3v. When a remote device initiates a connection, this
pin goes low. This means that when this pin is converted to RS232 voltage levels it will have the
correct voltage level for assertion.
Pin 8 (UART_DCD) is active low. It is normally 3.3v. When a connection is live this pin is low. This
means that when this pin is converted to RS232 voltage levels it will have the correct voltage level for
assertion.
Pin 10 (UART_DSR) is an input, with active low logic. It should be connected to the DTR output of the
host. When the BISM2 Module is in high speed mode (See definition for S Register 512), this pin
should be asserted by the host to ensure that the connection is maintained. A deassertion is taken to
mean that the connection should be dropped, or an online command mode is being requested.
The GPIO pins can be accessed using S Registers 621 to 625. GPIO4 and GPIO5 are also connected
to LEDs on the module. If these I/O pins are set for input, then the LED will be driven by the host and
appropriate drive current requirements must be satisfied. By default GPIO4 is used to drive the right
LED which indicates connection status. A Logic 1 switches on the LED.
GPIO3 is used for DTR output (active low).
Analogue 0 and 1 should not exceed 1.8v and S Registers 7xx are used to access them.
3.3 Electrical Specifications
3.3.1 Absolute Maximum ratings
Absolute maximum ratings for supply voltage and voltages on digital and analog pins of the Module
are listed below; exceeding these values will cause permanent damage.
Parameter Min Max Unit
Peak current of power supply 0 100 mA
Voltage at digital pins -0.3 3.7 V
Voltage at POWER pin 3.3 7 V
3.3.2 Recommended Operating Parameters
3.3.2.1 Power Supply
Signal Name Pin No I/O Signal level Comments
Vcc 29 I 3.6V to 6V I
GND 11, 15, 18,
6 Ground terminals to be attached
30, 36, 38
VCC_1V8 39 O 1.8V typical For monitoring only. No current
VCC_3V3 27 O 3.3V typical For monitoring only. No current
The current drain from the Vcc power input line is dependent on various factors. The three most
significant factors are the voltage level at Vcc, UART Baudrate and the operating mode.
The hardware specification for the Module allows for a voltage range of 3.6 to 6.0 at Vcc. Tests have
shown that there is no significant difference in current draw when Vcc is 5 or 6V. Therefore the data
presented below, pertains to Vcc levels of 3.6 and 5v only. Tests have shown that where power drain
is an issue, it is best to keep Vcc at the lower end of the range.
The UART baudrate has a bearing on power drain because as is normal for digital electronics, the
power requirements increase linearly with increasing clocking frequencies. Hence higher baudrates
result in a higher current drain.
Finally with regards to operating mode the significant modes are; idle, waiting for a connection,
inquiring, initiating a connection, sniff and connected. With connected mode, it is also relevant to
differentiate between no data being transferred and when data is being transferred at the maximum
rate possible. The AT command Set document describes how to configure the Module for optimal
power performance.
4.1.1 Typical Current Consumption in mA
Baudrate
9600 38400 115200 460800
3.6v 1.60 1.80 1.96 3.00 Idle Mode, S512=1
5.0v 2.00 2.10 2.30 3.40
3.6v 59.00 59.00 59.00 59.00 Wait for Connection Or Discoverable Mode,
AT+BTP
S508=S510=640, S509=S511=320
AT+BTP
S508=S510=1000, S509=S511=11*
5.0v 65.00 65.00 65.00 65.00
3.6v 2.75 2.94 3.10 4.12 Wait for Connection Or Discoverable Mode,
Conducted Transmit Power min: 1.0mW (0dBm) max: 4mW (6dBm)
Antenna Gain +2dBi typ.
Effective Transmit Power min: 0dBm max Max: +6dBm
5.1.2 Receive Sensitivity
Receive Sensitivity -86dBm (at 25°C)
Antenna Gain +2dBi typ
Effective Receive Sensitivity -88dBm (at 25°C)
5.1.3 RF Performance Data
Attenuation Setting dBm
-100
0
-40 deg
-10
-20
-30
-40
-50
-60
-70
-80
-90
Receive Sensitivity
-20 deg0 deg20 deg40 deg60 deg80 deg100 deg
NOTE: Measured as attenuation required
to achieve better than 0.1% BER
Temperature Deg. C.
5.2 Range
See the Data Transfer Rate vs distance graph below. The data throughput of the Module is limited to
280Kbps by the parsing of the data being transferred through the AT command processor. The graph
below shows the typical data thoughput with and without the AT command processing. Distances are
measured in free space between 2 Modules.
The BISM2 Bluetooth module is a self-contained Bluetooth product and requires only power to
implement full Bluetooth communication. The integrated, high performance antenna together with the
RF and Base-band circuitry provides the Bluetooth wireless link and the UART interface provides a
connection to the host system.
The variety of interfaces and the AT command set allow the BISM2 module to be used for a wide
number of short range wireless applications, from simple cable replacement to complex multipoint
applications, where multiple radio links are active at the same time.
The complexity and flexibility of configuration are made simple for the design engineer by the
integration of a extremely comprehensive set of AT commands, supplemented with a range of “S”
registers which are used for non=volatile storage of system parameters. These are fully documented
in the “Blu2i AT Command Reference Manual”.
To provide the widest scope for integration a range of different physical host interfaces are provided:
6.1 Interfaces
6.1.1 UART interface
UART_TX, UART_RX, UART_RTS and UART_CTS form a conventional asynchronous serial data port.
The interface is designed to operate correctly when connected to other UART devices such as the
16550A. The signalling levels are nominal 0V and 3.3V and are inverted with respect to the signalling
on an RS232 cable. The interface is programmable over a variety of bit rates; no, even or odd parity;
stop bit and hardware flow control. The default condition on power-up is pre-assigned in the external
Flash. Two-way hardware flow control is implemented by UART_RTS and UART_CTS. UART_RTS is an
output and is active low. UART_CTS is an input and is active low. These signals operate according to
normal industry convention.
By writing different values to the S register the UART_RI can be continuously polled to detect
incoming communication. The UART_RI signal serves to indicate incoming calls.
UART_DSR is an active low input. It should be connected to DTR output of the host. When the module
is running in high speed mode (See definition for S Reg 512), this pin should be asserted by the host
to ensure connection is maintained. A de-assertion is taken to mean that the connection should be
dropped, or an online command mode is being requested.
The module communicates with the customer application using the following signals:
RS-232
Port /TXD @ application sends data to the module’s UART_RX signal line
Port /RXD @ application receives data from the module’s UART_TX signal line
The Module is a slave device that uses terminals SPI_MOSI, SPI_MISO, SPI_CLK and SPI_CSB. This
interface is used for program firmware update.
Note: The designer should be aware that no security protection is built into the hardware or firmware
associated with this port, so the terminals should not be permanently connected in a PC application.
6.1.3 GPIO Port
Eight lines of programmable bi-directional input/outputs (I/O) are provided that can be accessed
either via the UART port, or Over The Air from a second Bluetooth unit. These can be used as data
inputs or to control external equipment. By using these in OTA mode, a BISM21 module can be used
for control and data acquisition without the need for any additional host processor.
Each of the GPIO[1:8] ports can be independently configured to be either an Input or Output. A
selection of ports can be accessed synchronously.
GPIO 1 and 2 can be configured as event counters.
The ports are powered from V
accessed via S Registers 621 to 625.
Low latency I/O can be accessed by using Ezurio’s I/O via enquiry process.
. The mode of these lines can be configured and the lines are
CC
6.1.4 PCM CODEC Interface
PCM_OUT, PCM_IN, PCM_CLK and PCM_SYNC carry up to three bi-directional channels of voice data,
each at 8ksamples/s. The format of the PCM samples can be 8-bit A-law, 8-bit µ-law, 13-bit linear or
16-bit linear. The PCM_CLK and PCM_SYNC terminals can be configured as inputs or outputs,
depending on whether the module is the Master or Slave of the PCM interface.
The Module is compatible with the Motorola SSI TM interface and interfaces directly to PCM audio
devices including the following:
6.1.4.1 Compatible Codec Chips
•
Qualcomm MSM 3000 series and MSM 5000 series CDMA baseband devices
•
OKI MSM7705 four channel A-law and µ-law CODEC
•
Motorola MC145481 8-bit A-law and µ-law CODEC
•
Motorola MC145483 13-bit linear CODEC
6.1.5 ADC
The BISM2 provides access to two 8-bit ADCs are available. These provide a range o 0mV to
1,800mV, which can be read using the S registers 701 and 702.
Suitable external scaling and over-voltage protection should be incorporated in your design.
The BISM2 has been designed to provide the fastest route to market for designers who wish to use
Bluetooth to wirelessly enable their products. To achieve this Ezurio has implemented a wide ranging
set of AT commands that control all of the standard Bluetooth tasks. These remove the complexity of
Bluetooth from the design engineer and allow the wireless link to be controlled by means of a simple
set of commands.
For applications where multiple concurrent live connections need to be maintained a variant of
firmware is available which is specifically targeted at multipoint operation.
For both applications a comprehensive range of windows based software and is available to speed up
the design process. A low cost development kit is also available that can be used for prototyping both
cable replacement and multipoint applications.
7.2 Profiles
Bluetooth has been designed to accommodate a very wide range of wireless applications. To enable
these different applications the Bluetooth SIG (Special Interest Group) has defined a series of
different profiles that define the way in which Bluetooth devices communicate with each other and
perform basic functions. These provide a base line of interoperability for specific application
scenarios, upon which more complex user applications can be developed.
There are over 30 different profiles, many of which have been developed for specific applications.
The BISM2 firmware is provided with support for the profiles that are most commonly required for
cable replacement applications.
The current profiles support includes:
•
GAP Generic Access Profile. The base connection profile upon which others are based.
•
SDP Service Discovery Profile. The profile to find other Bluetooth devices and the services
they support.
•
SPP Serial Port Profile. Emulation of a serial cable for cable replacement applications.
•
DUN Dial Up Networking. Profile support for connection to an external PSTN, GSM, GPRS
or VPN connection.
•
Audio Gateway. The base element for Headset and Handsfree profile. A portion of these
profiles must be implemented within the host system.
For other profile support, please contact Ezurio Ltd at blu2i@ezurio.com
7.3 AT Overview
The AT command set is well known by engineers and was developed to aid the integration of PSTN
modems. It provides simple high level commands for complex functions that can easily be
incorporated into programs or used within programming scripts.
Ezurio has used this familiar concept and extended it to Bluetooth to simplify the integration of
Bluetooth for product designers. Rather than having to understand the many stages of setting up a
Bluetooth connection or function, a single AT command is all that is required.
For example to connect to a Bluetooth device with an address 00809844EA13, all that is needed is to
send the string
ATD00809844EA13
to the UART of the BISM2 module. The module will attempt to make a connection and return OK or
ERROR, depending o whether the connection was successful.
The complexity of the AT command set developed by Ezurio is such that most Bluetooth functionality
can be covered, greatly reducing development time.
To provide additional functionality a range of “S” registers has been implemented. These allow
program settings to be stored to control the BISM2 function and also give access to configuring and
reading ports and status registers within the BISM2.
Full details of the AT command set are provided in the Blu2i AT Command Reference Manual.
7.3.1 AT features at a glance
7.3.1.1 General
•
Configure two modules to automatically connect and transfer data, audio or a combination of
data and audio when both devices are powered.
•
Automatically re-connect devices when a connection is dropped.
•
Remotely access the AT parser of the remote unit from a master device to perform Over The
Air (OTA) configuration.
•
Configure the module to enter a state on power up and after a period of time change to
another state automatically
•
Read and write to GPIO lines
•
Read the ADC channels
•
Get fast GPIO status through an inquiry response (patent pending)
7.3.1.2 Audio
•
Set up audio connections
•
Enable / disable Auto Answer for incoming connections
7.3.1.3 UART
•
Change the baud rate from 1200 to 961,200 baud.
•
Use the DSR line to drop connections
•
Configure as DTE or DCE
•
Change escape sequence character
•
Change the number of Stop bits and Parity
•
Enable or disable echoes
7.3.1.4 Security
•
Enable Authentication by requiring a PIN code for incoming AND / OR outgoing connections
•
Enable data to be encrypted over the air for incoming AND / OR outgoing connections. The
module can be configured to be:
non-connectable and non-discoverable,
non-connectable but discoverable,
connectable but non-discoverable,
connectable and discoverable.
•
Automatically store Paired devices in a trusted device database in the flash memory
7.3.1.5 Bluetooth
•
Set the module to be a master or slave
•
Make a Bluetooth connection to a specified device
•
Perform a full inquiry for other Bluetooth devices
•
Query a remote device to check if a service is offered
Increase or decrease the delay before the master abandons a connection attempt
•
Change the device class code
•
Set the device’s friendly name
•
Change the Inquiry scan time
•
Change number of returned devices from an inquiry scan
•
Obtain the RSSI value for a connection
7.3.1.6 Power Management
•
Decrease or increase the output power to suit your connection range
•
Configure the modules to work in Sniff and other low power modes.
7.4 Multipoint Firmware
The Module consists of the same hardware as that used for the single point ‘AT’ blu2i module
described elsewhere. Whereas the latter only allows one-to-one connection, the module described
here allows simultaneous connections to a minimum of 3 slaves, and depending on hardware build,
up to 7 slaves. It also allows connections to multiple profiles to one or more slaves. Hence this
document adopts a concept of channels instead of slave connections.
The term ‘host’ in this document is taken to mean any entity which is a source of command
messages, sink for response/event messages and both source and sink for multiplexed data packets.
7.5 OTA (Over the Air) Configuration
When the BISM2 is placed in slave mode it’s settings can be remotely controlled by a master unit.
This places the slave unit’s AT parser in remote mode providing over the air configuration. This mode
is of use for remote sensor applications, where no host processor is required to control the slave
Bluetooth unit.
7.6 Bootmodes
The module has the capability of booting into 1 of 8 modes. These will be supported in future
releases of firmware and selected via an S Register.
Boot Mode 1 is default and gives functionality equivalent to the BISM1 module.
These modes will specify different PSKEY settings to allow for different basic operation. Please
contact Ezurio for further information.
8. Low Power Modes
The current drain from the Vcc power input line is dependent on various factors. The three most
significant factors are the voltage level at Vcc, UART baud rate and the operating mode.
The hardware specification for the blu2i module allows for a voltage range of 3.6 to 6.0v at Vcc. Tests
have shown that there is no significant difference in current draw when Vcc is 5 or 6V. Therefore the
data presented below, pertains to Vcc levels of 3.6 and 5v only. Tests have shown that where power
drain is an issue, it is best to keep Vcc at the lower end of the range.
The UART baud rate has a bearing on power drain because as is normal for digital electronics, the
power requirements increase linearly with increasing clocking frequencies. Hence higher baud rates
result in a higher current drain.
Finally with regards to operating mode the significant modes are; idle, waiting for a connection,
inquiring, initiating a connection and connected. With connected mode, it is also relevant to
differentiate between no data being transferred and when data is being transferred at the maximum
rate possible.
The operating mode can best be described by stating the AT commands required to enter that mode.
In addition, there are certain S Registers which have a direct impact on power consumption, which
are described next.
The blu2i Module has 2 LEDs which can be configured to display connection status. One led is used to
display connection status, while the other is used to either display ‘Ring Indicate’ status or follow the
state of the incoming DSR line on the UART interface. Tests have shown that these LEDs can consume
up to 5.3mA which is more than double the current draw when in Idle mode. Therefore S Registers
533 and 534 can be used to completely disable these indications.
Finally S Registers 508 to 511, which specify the page and inquiry scan intervals and windows, can be
used to adjust the average current drain when in discoverable and or connectable modes. Registers
508 and 509 specify the interval and window for page scans and registers 510 and 511 specify the
interval and window for inquiry scans. Register pairs 508/509 and 510/511 describe duty cycles when
the blu2i module goes into scan modes. It is while scanning that the highest current draw occurs. The
average current draw is determined by simple arithmetic using the values stored in the 508/509 and
510/511 register pairs.
The operating modes described above are entered using AT commands as follows
Idle On power up, with S Register 512 = 1
Wait for Connection AT+BTG (100% page scan duty cycle)
Discoverable Only AT+BTQ (100% inquiry scan duty cycle)
Connecting ATD
Connected No Data
Connected Max data transfer
All current consumption values in the table below assume that the connection status indication
functionality of the LED has been disabled by setting S Registers 533 and 534 to 0.
Baud rate
9,600 38,400 115,200 460,800
3.6V 1.60 1.80 1.96 3.00 Idle Mode, S512=1
5.0V 2.00 2.10 2.30 3.40
3.6V 59.00 59.00 59.00 59.00 Wait for Connection Or Discoverable
Mode, AT+BTP
5.0V 65.00 65.00 65.00 65.00
S508=S510=640, S509=S511=320
3.6V 2.75 2.94 3.10 4.12 Wait for Connection Or Discoverable
Mode, AT+BTP S508=S510=1000,
S509=S511=11
As can be seen, the current drain while waiting for a connection or discoverable mode is about 30
times higher than in idle mode. This is when the page/inquiry scan duty cycle is 100%. These modes
give the quickest response to a page or inquiry request from a remote peer.
It is possible to reduce the duty cycle down to as low as 0.5% at the expense of response time. The
response time can be specified via S Registers 508 and 510 for page and inquiry respectively, where
the worst case response time can be as high as 2.5 seconds. Then the duty cycle can be varied by
changing the value of S Registers 509 and 511 appropriately.
For example, if S Register 508 and 510 are both set to 1000ms and S Register 509 and 511 are both
set to 11ms then the duty cycle is reduced to 1%, this means that average current drain at 5.0v will
be 2% of 65mA plus the normal idle mode current, that is, it is as low as 2.75mA. However, in this
case, it can take up to 1 second to establish a connection.
The connected state current consumption while a master or slave can be considerably reduced by
enabling Sniff mode, described in detail in the next section.
3.6V 21.50 22.50 24.50 32.50
5.0V 24.50 26.00 28.00 36.00
5.0V 32.00 33.00 33.50 34.00
5.0V 4.90
mA
3.6V 3.20 Current per LED (when fitted)
5.0V 5.30
8.1 Low Power Modes using Sniff
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 as illustrated in the power table above, where a slave with no data transmission still
consumes around 31mA whereas a master consumes only 6mA.
This problem was identified very early in the evolution of Bluetooth (especially since headsets spend
all their time as a slave in a Bluetooth connection) and it 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 N-M slots, and so can switch its power hungry circuitry off. The
specification goes further by also specifying a third parameter called ‘timeout’ (T) which specifies
‘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
specification states that a master can have up to 7 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 specifies 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 specified in the BISM2 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 specification defines these
parameters in terms of timeslots, the S register values have to be specified in units of milliseconds
and the firmware does the necessary translation to timeslots.
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9. Application Examples
9.1 RS232 Modem Signals
Just as a telephony modem has control and status lines, the blu2i Module also provides for 6 control
and status lines as per the table below. The direction column is as seen from the module’s viewpoint.
Direction Function
IN or OUT CI also known as RI (Ring Indicate)
IN or OUT DCD (Data Carrier Detect)
IN DSR (Data Set ready)
OUT DTR (Data Terminal Ready)
IN CTS (Clear to Send)
OUT RTS (Request to Send)
The first four lines are under program control. These use four of the GPIO pins and are mapped to
I/O as per the table below. The last two are under control of the UART driver and their functionality is
always enabled.
PIO Pin Direction Connector Pin Label Function
0 IN/OUT GPIO1 General Purpose I/O
1 IN/OUT GPIO2 General Purpose I/O
2 IN/OUT UART_RI Input/Output from module
3 IN/OUT UART_DCD Input/Output from module
4 IN UART_DSR Input to Module
5 IN/OUT GPIO3/UART_DTR General Purpose I/O (or DTR functionality)
1. PIO4 (DSR) is used by the blu2i module to sense that the host is connected, and is intricately
linked with connections. For outgoing calls, if this line is not asserted then an error is indicated.
Similarly for AT+BTP and AT+BTG.
While in a call, for appropriate modes, a de-assertion means fall into command state. If the deassertion exists for longer than the period specified in S Register 519 then the connection is dropped
as if an ATH command was received.
2. PIO2 (RI), is normally de-asserted. When an incoming connection is detected it will be
asserted, until the connection is either answered or rejected using ATA and ATH respectively. See S
Registers 552 & 553 for more details
3. PIO3 (DCD) will be de-asserted when the device is in the unconnected state. Asserted when a
connection is active. See S Registers 552 and 553 for more details.
4. PIO5 is either used as GPIO or driven as UART_DTR. When the unit is configured in pure host
mode, this pin is forced into UART_DTR and is asserted when there is a Bluetooth connection.
GPIO Pins 1,2,3,4 and 5 are available for general purpose use.
9.2 Modem signalling over Bluetooth
The RFCOMM protocol used in Bluetooth for implementing the serial port profile allows for the
exchange of four modem signals. This information is contained in a special transparent message
which contains bits identified as RTR, RTC, DV and IC which depending on the type of serial device
being emulated maps to DTR or DSR, RTS, DCD and RI respectively. In addition, this message also
includes the ability to convey a BREAK input from one end to the other.
To allow for the greatest flexibility and variability in how the modem control signals are used out in
the real world, S Registers 551, 552 and 553 have been provided which allow for any of RTR,RTC,DV
and IC to be mapped to any modem control/status line.
BREAK signal on RX line
If the host sends a break signal of duration greater than 100ms, then the blu2i module is
configured to treat that as a signal to perform a hardware reset.
This being the case it is not possible to convey a BREAK over Bluetooth to the peer device.
Reset
The module can be reset by the host without the need of any I/O using a BREAK signal. The
module has been configured to reset when the RX line detects a break condition for durations
greater than 100 milliseconds.
9.3 Pure Cable Replacement Mode
The module has the capability of being preset into a pure 5-wire data cable replacement mode. The 5
wires being RX, TX, CTS, RTS and GND. This mode requires no changes to a host application since
the Bluetooth connection is automatically set up on power up. If the connection is lost the BISM2
module will constantly retry until the connection is reinstated.
By implication, two devices are needed to replace a cable. One device is pre-configured to always be
a master and the other, a slave.
Assuming the Bluetooth address of the master to be <bdaddr_m> and that of the slave to be
<bdaddr_s>, the master module is configured by sending it the following AT commands:
The ATS507=2 setting puts the device in DSR drop mode only. This means that when the device
needs to be reconfigured, deasserting the DSR line will ensure that the module responds quickly to AT
commands. This further means that in stand alone mode, the DSR input line MUST be asserted e.g.
0V in TTL signal mode.
The slave is configured by:
AT&F
ATS512=4
ATS0=-1
AT&W
AT+BTR<bdaddr_m>
Where <bdaddr_m> is optional. If it is not specified, then the slave unit will accept connections from
any device. If specified then only connections from the device specified will be accepted.
If it is desired that the slave unit should not be discoverable (the master is by default not
discoverable), then the configuration commands are:
AT&F
ATS512=3
ATS0=-1
AT&W
AT+BTR<bdaddr_m>
Where <bdaddr_m> is optional. If it is not specified, then the slave unit will accept connections from
any device. If specified then only connections from the device specified will be accepted.
When the units are next power cycled, the slave unit will wait for the master to connect to it and the
master will continually look for the slave. If a connection attempt fails, the master will wait for 2
seconds before reattempting a connection. This 2 second delay can be varied by issuing it an ATS530
command with an appropriate value in the range 100ms to 15000ms.
IMPORTANT NOTE: When S Register 507 = 0, the DSR input to the module MUST be asserted for the
auto connection to succeed. When operating at TTL levels a 0V is seen as an assert state. When
operating at RS232 levels and voltage greater than 3V is seen as assert. It is usual to connect the
DTR line of the host to the DSR line of this device.
9.4 Audio Cable (voice)
With a pair of these modules it is possible to replace a mono audio cable with two way traffic. That is,
a setup where a microphone is connected to a speaker at the remote end and vice versa. So this
mode effectively replaces two audio cables.
Assuming the Bluetooth address of the master to be <bdaddr_m> and that of the slave to be
<bdaddr_s>, the master module is configured by sending it the following AT commands:
A serial port has DTR, DSR, RTS, CTS, DCD and RI control lines. RTS and CTS are locally controlled to
prevent local buffer overflow.
However the status of DTR, DRS, DCD and RI can be exchanged with the remote peer device. If for
example, the DTR/DSR lines are to be exchanged between the two peers to simulate the performance
of a physical cable, then it is possible to do so. Refer to the description for S Registers 551, 552 and
553 for more details.
The antenna used on the BISM2 Bluetooth module is designed to be largely immune from the effects
of proximity detuning. Normally, antennas operating at 2.4GHz are affected by their surroundings, so
that great care is needed in their placement and orientation.
The BISM2 can be used in most locations and orientations and is only marginally affected by the
presence of a significant ground plane in close proximity.
The antenna distribution is close to isotropic, which means that the orientation of mounting has only
a limited effect on the overall range. However the optimum range is achieved when the two
antennae are directly facing each other
The module should not be located in a sealed metal enclosure, as this will act as a Faraday cage and
prevent the radio signal from penetrating.
10.2 Power Supply Considerations
The power supply for the Module has to be a single voltage source of Vcc within the range of 3.3 V to
6.0 V. It must be able to provide sufficient current in a transmit burst. This can rise to 65mA.
The Module includes regulators to provide local 3.3V. This rail is accessible on connector J2 for
monitoring purposes only. Under no circumstances should this pin be used to source current.
Power (Vcc) can be provided via the board-to-board connector Pin 29 on J2.
10.3 Power-On-Reset (Power Cycling and Brown Out
considerations).
The Module is provided with an active low reset pin (Hirose 40way DF12C connector pin 13). Upon
the application of power, the Power On Reset circuit built into the Module will ensure that the unit
starts correctly. There is no need for an external power reset monitor.
10.4 Mounting the Module onto the application platform
There are many ways to properly install the Module in the host device. An efficient approach is to
mount the PCB to a frame, plate, rack or chassis. Fasteners can be M1.8 or M2 screws plus suitable
washers, circuit board spacers, or customized screws, clamps, or brackets in 2.2mm diameter holes.
Note that care should be taken to ensure the head of the fixing does not interfere with the circuit.
Nylon fixings are recommended. In addition, the board-to-board connection can also be utilized to
achieve better support.
The antenna (Brown square component on top side of PCB) must not be influenced by any other
PCBs, components or by the housing of the host device. The proximity of the antenna to large
metallic objects can affect the range and performance of the system. Designers should carefully
consider the location of the Module and the type of enclosure material that is used.
To prevent mechanical damage, be careful not to force, bend or twist the Module. Be sure it is
positioned flat against the host device.
This chapter provides specifications for the 40-pin board-to-board connector which serves as physical
interface to the host application. The receptacle assembled on the Module is Hirose type DF12C.
Details are available at: http://www.hirose.co.jp/cat2002e/500/e53700036.pdf
11.1 Stacking Height
Mating headers from Hirose are available in different stacking heights, allowing the spacing between
the BISM2 and carrier pcb to be changed from 3.5mm to 5.0mm.
Item Part number Stacking height HRS number
Receptacle on
Module
Headers DF12 series DF12(3.5)-40DP-0.5V(81) 3.5 mm CL537-0032-4-**
DF12(4.0)-40DP-0.5V(81)
DF12(5.0)-40DP-0.5V(81)
Notes: The headers listed above are without boss and metal fitting.
DF12C-40DS-0.5V(81) 3.5 mm – 5 mm CL537-0007-7-
4.0 mm CL537-0057-5-**
5.0 mm
CL537-0157-0-**
11.2 Hirose Connector general specification
Parameter Specification (40 pin Board to Board connector)
Number of Contacts 40
Quantity delivered 2000 Connectors per Tape & Reel
Voltage 50V
Current Rating 0.5A max per contact
Resistance 0.05 Ohm per contact
Dielectric Withstanding Voltage 500V RMS min
Operating Temperature -45°C...+125°C
Contact Material phosphor bronze (surface: gold plated)
The following safety precautions must be observed during all phases of the operation, usage, service
or repair of any application incorporating this Module. Manufacturers of the RF equipment are advised
to convey the following safety information to users and operating personnel and to incorporate these
guidelines into all manuals supplied with the product. Failure to comply with these precautions
violates safety standards of design, manufacture and intended use of the product. Ezurio assumes no
liability for customer failure to comply with these precautions.
12.2 Safety Information:
Switch off the Bluetooth device before boarding an aircraft. Make sure it cannot be switched on
inadvertently. The operation of wireless appliances in an aircraft is forbidden by many airlines to
prevent interference with communications systems. Applications that could result in use on aircraft
should carry appropriate warnings.
12.3 Qualifications
12.3.1 RF approvals
The Module is listed as a Bluetooth Product in terms of the Bluetooth SIG Program Reference
Document (PRD). This means that it can be integrated into end products without further testing or
approval listing. The manufacturer must state the Ezurio part number and product reference in his
literature in order to meet the requirements of the Bluetooth and regulatory approvals.
A list of the countries where the Module is approved will be provided by Ezurio as required. As a
minimum the product is listed in Europe and USA. Ezurio assumes no liability for customer failure to
comply with national RF approvals.
In accordance with Annex IV of the EU directive 1999/5/EC
Notified Body consulted: Phoenix Test-Lab
ID-Number of Notified Body: 0700
declare under our responsibility that the blu2i Module
complies with the appropriate essential requirements of the Article 3 of
the R&TTE and the other relevant provisions, when used for its intended
purpose.
Health and Safety requirements contained in Article 3 (1) a)
EN 60 950: 1992 Safety of information technology equipment +
Amendment A1:1993, Amendment A2:1993, Amendment A3:1995,
Amendment A4:1997, Amendment A11:1997
EN 50371: Generic standard to demonstrate the compliance of lowpower electronic and electrical apparatus with the basic restrictions
related to human exposure to electromagnetic fields (10 MHz - 300 GHz)
– General public
Protection requirements with respect to electromagnetic compatibility
Art.3 (1) b)
EN 301489-17 V1.1.1 (09-2000), Electromagnetic Compatibility and
radio spectrum Matters (ERM); Electro Magnetic Compatibility (EMC)
standard for radio equipment and services; Part 17: Specific conditions
for wideband data HiperLAN equipment
Means of the efficient use of the radio frequency spectrum
EN 300328-2 V1.2.1 (11-2001), Radio Equipment and Systems (RES);
Wideband transmission systems; Technical characteristics and test
conditions for data transmission equipment operating in the 2,4 GHz
ISM band and using spread spectrum modulation techniques. Part 2:
Harmonized EN covering essential requirements under article 3(2) of the
R&TTE directive.
Ezurio Ltd tel: +44 (0)20 8938 1000
Unit 2, 126 Colindale Avenue, Colindale fax: +44 (0)20 8905 8608 Registered in England
London NW9 5HD, United Kingdom www.ezurio.com No. 5178293
This device complies with part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) This device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
Changes or modifications not expressly approved by the party responsible for compliance could void
the user's authority to operate the equipment.
13. Environmental
13.1 Operating temperatures
Parameter Min Typ Max Unit
Operating temp (standard product) -40 25 +85 °C
13.2 Storage temperature
Parameter Min Max Unit
Storage temp -40 +125 °C
13.3 Reliability
Parameter Test Comment
Thermal Shock 200 cycles -40ºC /+85ºC 30 min 1 cycle/hour
Vibration Continuous operation at 60 Hz,
2mm stroke
Shock 50G 11ms Half Sine Wave 6 axis x 3 cycles each axis
Moisture Resistance
High Temp Storage 85ºC, 360 hours
Low Temp Storage -40ºC, 240 hours
High Temp/Humidity
Operation
Thermal shock -40 to 60ºC in 30min 200 cycles with continuous
EZURIO’S BLUETOOTH PRODUCTS ARE NOT AUTHORISED FOR USE AS CRITICAL COMPONENTS IN
LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE
MANAGING DIRECTOR OF EZURIO LTD.
The definitions used herein are:
a) Life support devices or systems are devices which (1) are intended for surgical implant into the
body, or (2) support or sustain life and whose failure to perform when properly used in accordance
with the instructions for use provided in the labelling can reasonably be expected to result in a
significant injury to the user.
b) A critical component is any component of a life support device or system whose failure to perform
can be reasonably expected to cause the failure of the life support device or system, or to affect its
safety or effectiveness.
Ezurio does not assume responsibility for use of any of the circuitry described, no circuit patent
licenses are implied and Ezurio reserves the right at any time to change without notice said circuitry
and specifications.
17.1 Data Sheet Status
This data sheet contains data from the Preliminary specification. Supplementary data will be
published at a later date. Ezurio Ltd reserve the right to change the specification without notice in
order to improve the design and supply the best possible product.
Please check with Ezurio Ltd for the most recent data before initiating or completing a design.
17.2 Warranty
Ezurio warrants that its products shall conform to Ezurio’s published specifications and remain free
from defects in materials and workmanship under normal, proper and intended use for a period of
two (2) years from date of purchase, provided that proof of purchase be furnished with any returned
equipment.
If during the warranty period any component part of the equipment becomes defective by reason of
material or workmanship, and Ezurio is immediately notified of such defect, Ezurio shall at its option
supply a replacement part or request return of equipment, freight prepaid, to its designated facility
for repair. In the event no trouble is found on products returned for repair, Ezurio reserves the right
to charge the customer its standard published repair charge.
This warranty shall not apply to any products that have been subject to misuse, bending, twisting,
neglect, alteration, improper installation, testing or unauthorized repair performed by anyone other
than a Ezurio designated repair facility. Any non-warranty repairs or maintenance shall be at Ezurio’s
standard rates in effect at the time.
This warranty is in lieu of all other warranties, whether expressed, implied, or statutory, including but
not limited to, implied warranties or merchantability and fitness for a particular purpose. In no event
shall Ezurio be liable, whether in contract, in part, or on any other basis, for any damage sustained
by its customers or any other person arising from or related to loss of use, failure or interruption in
the operation of any products, or delay in maintenance, or for incidental, consequential, in direct, or
special damages or liabilities, or for loss of revenue, loss of business, or other financial loss arising
out of or in connection with the sale, lease, maintenance, use, performance, failure, or interruption of
these products.