Infineon A2B User manual

User guide Please read the sections “Important notice” and “Warnings” at the end of this document Rev.1.10
www.infineon.com 2022-05-05
User guide
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of
XENSIV digital MEMS microphones, using the A²B interface in
combination with the AURIX microcontroller
About this document
Scope and purpose
This user guide describes the usage and basic operation of the A²B evaluation kit. It describes the parts of the
kit and includes schematic and pinout of the individual boards.
Intended audience
Hardware and software engineers, evaluating Infineon digital XENSIV™MEMS microphones.
Evaluation kit
This evaluation kit allows multi microphone audio readout and processing for many applications (e.g. siren
detection, beam forming, in-cabin-communication, active noise cancellation, …). It can be used by customers
to develop their own algorithms and experiment with different numbers of microphones in different locations
inside or outside of the car. With its magnetic microphone slave modules, it allows easy mounting on any metal
surface.
The microphone slave modules are equipped with protective membranes in front of the microphone sound
ports and silicon gaskets on the cable feed throughs. This allows real driving test and the data collection even
under dusty and slightly wet conditions.
It also shows how to connect the Infineon digital XENSIV™ MEMS microphones to an A²B transceiver and how to
interface to the AURIX™ microcontroller.
Note: PCB and auxiliary circuits are NOT optimized for final customer design.
A²B evaluation kit with the ECU master unit and 4 microphone slave modules.

User guide 2 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Important notice
Important notice
“Evaluation Boards and Reference Boards” shall mean products embedded on a printed circuit board
(PCB) for demonstration and/or evaluation purposes, which include, without limitation, demonstration,
reference and evaluation boards, kits and design (collectively referred to as “Reference Board”).
Environmental conditions have been considered in the design of the Evaluation Boards and Reference
Boards provided by Infineon Technologies. The design of the Evaluation Boards and Reference Boards
has been tested by Infineon Technologies only as described in this document. The design is not qualified
in terms of safety requirements, manufacturing and operation over the entire operating temperature
range or lifetime.
The Evaluation Boards and Reference Boards provided by Infineon Technologies are subject to functional
testing only under typical load conditions. Evaluation Boards and Reference Boards are not subject to the
same procedures as regular products regarding returned material analysis (RMA), process change
notification (PCN) and product discontinuation (PD).
Evaluation Boards and Reference Boards are not commercialized products, and are solely intended for
evaluation and testing purposes. In particular, they shall not be used for reliability testing or production.
The Evaluation Boards and Reference Boards may therefore not comply with CE or similar standards
(including but not limited to the EMC Directive 2004/EC/108 and the EMC Act) and may not fulfill other
requirements of the country in which they are operated by the customer. The customer shall ensure that
all Evaluation Boards and Reference Boards will be handled in a way which is compliant with the relevant
requirements and standards of the country in which they are operated.
The Evaluation Boards and Reference Boards as well as the information provided in this document are
addressed only to qualified and skilled technical staff, for laboratory usage, and shall be used and
managed according to the terms and conditions set forth in this document and in other related
documentation supplied with the respective Evaluation Board or Reference Board.
It is the responsibility of the customer’s technical departments to evaluate the suitability of the
Evaluation Boards and Reference Boards for the intended application, and to evaluate the completeness
and correctness of the information provided in this document with respect to such application.
The customer is obliged to ensure that the use of the Evaluation Boards and Reference Boards does not
cause any harm to persons or third-party property.
The Evaluation Boards and Reference Boards and any information in this document is provided "as is"
and Infineon Technologies disclaims any warranties, express or implied, including but not limited to
warranties of non-infringement of third-party rights and implied warranties of fitness for any purpose, or
for merchantability.
Infineon Technologies shall not be responsible for any damages resulting from the use of the Evaluation
Boards and Reference Boards and/or from any information provided in this document. The customer is
obliged to defend, indemnify and hold Infineon Technologies harmless from and against any claims or
damages arising out of or resulting from any use thereof.
Infineon Technologies reserves the right to modify this document and/or any information provided
herein at any time without further notice.

User guide 3 Rev.1.10
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Infineon A²B evaluation kit
Safety precautions
Safety precautions
Note: Please note the following warnings regarding the hazards associated with development systems.
Table 1 Safety precautions
Caution: The evaluation or reference board contains parts and assemblies sensitive to
electrostatic discharge (ESD). Electrostatic control precautions are required when
installing, testing, servicing or repairing the assembly. Component damage may result
if ESD control procedures are not followed. If you are not familiar with electrostatic
control procedures, refer to the applicable ESD protection handbooks and guidelines.
Caution: The evaluation or reference board is shipped with packing materials that
need to be removed prior to installation. Failure to remove all packing materials that
are unnecessary for system installation may result in overheating or abnormal
operating conditions.

User guide 4 Rev.1.10
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Infineon A²B evaluation kit
Table of contents
Table of contents
About this document....................................................................................................................... 1
Important notice ............................................................................................................................ 2
Safety precautions.......................................................................................................................... 3
Table of contents............................................................................................................................ 4
1The evaluation kit at a glance .................................................................................................. 5
1.1 Main features...........................................................................................................................................5
1.2 Scope of supply .......................................................................................................................................6
2Quick start ............................................................................................................................ 8
3System hardware and functional description ............................................................................ 9
3.1 ECU master unit.......................................................................................................................................9
3.1.1 AURIX™ lite kit...................................................................................................................................10
3.1.2 A²B master board .............................................................................................................................11
3.1.3 Microphone array extension board .................................................................................................12
3.2 Microphone slave module.....................................................................................................................13
3.2.1 Slave PCB..........................................................................................................................................13
3.2.2 Slave housing ...................................................................................................................................14
3.3 Cables ....................................................................................................................................................15
4Software ..............................................................................................................................16
4.1 General info ...........................................................................................................................................16
4.2 Demo software installed on the AURIX™ ..............................................................................................17
4.2.1 Realtime audio loop back................................................................................................................17
4.2.2 Live level meter ................................................................................................................................17
5System design.......................................................................................................................18
5.1 A²B master PCB .....................................................................................................................................18
5.1.1 Schematics .......................................................................................................................................18
5.1.2 Placement.........................................................................................................................................21
5.2 Microphone slave PCB...........................................................................................................................22
5.2.1 Schematics .......................................................................................................................................22
5.2.2 Placement.........................................................................................................................................24
5.3 Microphone array extension PCB .........................................................................................................25
5.3.1 Schematics .......................................................................................................................................25
5.3.2 Placement.........................................................................................................................................26
6Appendices...........................................................................................................................27
6.1 Abbreviations and glossary...................................................................................................................27
References....................................................................................................................................28
Revision history.............................................................................................................................29
Disclaimer.....................................................................................................................................30

User guide 5 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
1The evaluation kit at a glance
This evaluation kit is designed for customers who want to develop their own algorithms for sound detection
and experiment with different numbers of microphones in different locations inside or outside of the car.
It consists of an ECU master unit with an AURIX™microcontroller and several microphone slave modules with 4
MEMS microphones each. The audio data from the microphones are transmitted via A²B bus to the AURIX™. The
system can be configured, how many slave modules and which and how many microphones per slave shall be
used. The audio data of up to 8 microphones can be processed inside the AURIX™.
The user can then implement his own algorithm for processing the audio data on the microcontroller.
For easy start and simple demonstration, the AURIX™is pre-flashed with some simple demo code. Details can
be found in chapter 4.2.
1.1 Main features
•Full evaluation kit for multi microphone audio readout and processing for many different applications
•Target applications: Siren detection, hands-free speech, voice commands, beam-forming, in-cabin-
communication, active noise cancellation (ANC), …
•System can be used for driving tests outside on a demo car
•Phantom powered slave modules with 4 microphones each
•Slave PCB mounted in a spray water sealed housing
•Mountable to the outside of a car by magnets
•Aerodynamic shape to avoid audible air turbulences
•AURIX™sample code with up to 8 TDM channels
•Predefined configurations available
o4 slaves with 2 active microphones each
o2 slaves with 4 active microphones each
o1 slave with 4 active microphones
•Individual configuration via SigmaStudio possible
Figure 1 System overview of a possible A²B system outside of a car for siren detection

User guide 6 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
1.2 Scope of supply
The kit consists of a master unit and a variable number of slaves, cables and housings, which also can be
ordered separately.
1. ECU master unit:
a. Base microcontroller board
b. A²B master board
c. Microphone array extension with 15 LEDs
2. Housing for the ECU master unit
3. Power supply 12V
4. 1 … 4 slave modules, equipped with 4 MEMS microphones IM67D130A each
5. Magnetic housing for the slave board
6. Cables with different length to interconnect the master and the slaves
Figure 2 Components of the A²B Evaluation Kit

User guide 7 Rev.1.10
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Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
Table 2 Order information
Name
Item
Description
Order code
EVAL_A2B_Kit-Full
1x AURIX™ Lite Kit TC375
Complete A²B-Kit with all
boards, housings and cables
included (2 slaves)
SP005742620
1x A2B_Extension
(Mic-Array + A2B Master
Board)
2x EVAL_A2B_SIM67D130A
2x EVAL_A2B_S-Housing
1x EVAL_A2B_M-Housing
Cables 2x 25cm + 2x 400cm)
KIT_A2G_TC375_LITE
AURIX™ base board
AURIX™ Arduino shield as base
for the ECU master unit
SP005551747
EVAL_A2B_Extension
A²B master board
Extension for AURIX™ shield to
allow A²B operation
Note: AURIX Lite Kit TC375 and
housing not included
SP005742622
Microphone array extension
Extension for AURIX™ shield for
display purpose
Power supply 12V
Main power supply for the
whole evaluation kit
EVAL_A2B_SIM67D130A
1x microphone slave PCB
Slave PCB, equipped with 4
MEMS microphones IM67D130A
and one cable (housing not
included)
SP005742624
1x cable, ~25 cm
EVAL_A2B_S-Housing
Slave housing only
Magnetic housing for A2B_Slave
with gaskets and membranes
SP005742626
EVAL_A2B_M-Housing
Master housing only
Housing for A2B_Extension
(ECU master unit)
SP005742628
EVAL_A2B_Cable-025
1x cable only
Length: ~25 cm
Cable to interconnect the
master and the slaves for bench
tests
SP005742630
EVAL_A2B_Cable-400
1x cable only
Length: ~400 cm
Cable to interconnect the
master and the slaves for
driving tests
SP005742632

User guide 8 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
2Quick start
The following chapter describes the steps to connect, power-up and start the evaluation kit.
1. Connect the ECU master unit A²B output to the A²B connector “A” of the first slave
2. Connect the A²B connector “B” of the first slave to the A²B connector “A” of the second slave
3. Connect all slaves in the same manner (“B” of the previous slave to “A” of the next slave)
4. Connect the 12V power supply line to the A²B master board (Figure 6)
5. Apply power
6. Press the “RESET” button on the AURIX™ lite board (Figure 5)
7. Now the LED ring indicates the live sound level and an audio mix of all 8 microphones is available on the
headphone output of the A²B master board. Details can be found in chapter 4.2.
Figure 3 A²B evaluation board in operation with demo software

User guide 9 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
3System hardware and functional description
The following chapter describes and explains the different components of the evaluation kit.
3.1 ECU master unit
The master unit consists of three boards.
•AURIX™lite kit TC375
•A²B master board
•Microphone array extension
For operation, all three boards must be stacked together. The function and operations are described in the
chapters below.
Figure 4 Board stack of the ECU master unit

User guide 10 Rev.1.10
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Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
3.1.1 AURIX™ lite kit
Figure 5 AURIX™lite kit TC375 and its components as needed for the A²2B eval kit
•RESET:
oPressing the reset button will lead to a RESET of the AURIX™.
•Button 1:
oMultipurpose input for the AURIX™. Example of usage see chapter 4.2.
•Debug and USB
oEither of the two connectors can be used for programming and debugging purpose. For details,
please refer to [1].
Note: The power connector of the AURIX™lite kit must not be used, as the complete kit is powered via the
A²B master board.

User guide 11 Rev.1.10
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Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
3.1.2 A²B master board
Figure 6 A²B master board and its components
The master board consists of the following components:
•+12V power:
oCentral power connector for the complete evaluation kit
oThe kit can either be powered via the 12V plug and an AC/DC power supply or by connecting the
power terminals to a 12V car outlet.
•A²B bus connector:
o2-pin DuraClik connector (Molex 502352-0200) for the A²B bus; compatible to most other A²B
systems on the market.
•Line-in plug:
oAudio input for code evaluation
•Headphone plug:
oAudio output for debugging or connection to recording device
•SigmaStudio connector:
oDebug connection (optional) to allow configuration of the A²B transceivers via the
SigmaStudio® graphical development tool [5].
oTransceiver configuration can also be added directly in the source code. Predefined
configuration file can be downloaded from the AURIX™ code library on GitHub [3].
•A²B transceiver: AD2428WCCSZ01 –Analog Devices
•CODEC chip: ADAU1761BCPZ –Analog Devices
•Voltage regulator: TLS4120D0EPV –Infineon OPTIREG™Step-Down Regulator

User guide 12 Rev.1.10
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Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
3.1.3 Microphone array extension board
Figure 7 Microphone array extension board and its components
•Status LEDs:
oThree multipurpose LEDs
oControlled via GPIOs from the AURIX™
•LED ring:
oTwelve multipurpose LEDs (e.g. direction detection)
oControlled via GPIOs from the AURIX™
The default function of the different LEDs is described in chapter 4.2.
Details about the board can be found here: [2]

User guide 13 Rev.1.10
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Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
3.2 Microphone slave module
3.2.1 Slave PCB
Figure 8 Microphone slave PCB and its components
The microphone slave PCB is equipped with four XENSIV™ high performance microphones. The A²B transceiver
can be configured, which microphone channels to transmit to the ECU master unit via the A²B bus.
•MEMS microphones: Automotive qualified XENSIV™ digital MEMS microphones IM67D130A [4]
•A²B transceiver: AD2428WCCSZ01 –Analog Devices
•A²B bus connector:
oConnector A: connection towards master
oConnector B: connection towards last slave
o2-pin DuraClik connector (Molex 502352-0200) for the A²B bus; compatible to most other A²B
systems on the market.
•I2C interface: Optional connection for configuring of the A²B transceiver

User guide 14 Rev.1.10
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Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
3.2.2 Slave housing
Figure 9 Slave housing
•The magnetic slave housing allows easy mounting to all metal surfaces (e.g. car chassis) due to strong
magnets
•Protective membranes under the sound port protects the MEMS microphone from dust and water. See also
Figure 10.
Note: The protective membranes have an influence on the frequency response of the system. They can
be removed if needed, but then care must be taken to avoid particles or water to enter the
microphone sound port.
•Silicon gaskets around the connection cables to protect for intruding water
•Conical shaped sound ports for the microphones for improved frequency response
•Chamfered side walls to reduce air turbulences during driving tests
Attention: Make sure the metal surface underneath the slave is clean to avoid scratches on the lacquer
when mounting on a test car.
Figure 10 Protective membranes on the backside of the slave PCB

User guide 15 Rev.1.10
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Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
3.3 Cables
Figure 11 Cables for connection between ECU master unit and the slave boards
Cables to interconnect the master and the slaves can be ordered in different length. See also order information
in Table 2.
The cables are equipped with the 2-pin DuraClik connectors (Molex 502351-0200).

User guide 16 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
4Software
4.1 General info
•The PDM data from the digital MEMS microphones is filtered into a PCM audio signal on the A²B transceiver.
The audio data are then transferred to the ECU master unit via the A²B bus.
•The transceiver on the master board sends the data in an 8 channel TDM stream to the AURIX™. A conept
drawing of the I²S/TDM emulation and a timing diagram of the TDM stream are shown in Figure 12 and
Figure 13. For further details please refer to [2].
•Inside the AURIX™, the data are stored in 8 different buffers where the customer algorithm can access them
for further processing.
•The transceivers on the slave modules can be individually configured, which microphone channels should
be transmitted to the master.
•Sample code and different slave / microphone configurations can be found here [3].
Figure 12 Concept of the I²S emulation of the TDM stream
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User guide 17 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
Figure 13 Timing diagram of the 8 channel TDM stream
4.2 Demo software installed on the AURIX™
The evaluation kit is delivered with a preinstalled software. The following chapter describes the functions of the
demo software.
Note: The configuration might vary, depending on the order placed.
4.2.1 Realtime audio loop back
The system is configured to read the audio data from 8 microphones from 2 slave modules connected.
On the headphone-output one can hear a stereo-mix of all 8 microphone-channels in real-time.
Note: If more than two slaves are connected, only the first two slaves in the daisy chain will be active.
4.2.2 Live level meter
The LED ring of the microphone extension board are set up as a live level meter of the 8 different microphone
channels.
•The three status LED’s are showing in binary-count, which microphone-channel is selected to show the live-
level in the LED ring. See Figure 7.
•The channel selection can be changed by pushing the Button 1 on the AURIX™ board. See Figure 5.
•The LEDs are having a level-distance of 3dB.
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

User guide 18 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
5System design
5.1 A²B master PCB
5.1.1 Schematics
Figure 14 A²B master board: Schematic –page 1 of 3

User guide 19 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
Figure 15 A²B master board: Schematic –page 2 of 3

User guide 20 Rev.1.10
2022-05-05
Infineon A²B evaluation kit
Evaluation kit to experiment with different system configurations of XENSIV
digital MEMS microphones, using the A²B interface in combination with the
AURIX microcontroller
Table of contents
Figure 16 A²B master board: Schematic –page 3 of 3