Microchip Technology ATAK51005-V1 User manual

ATAN0219
ATAK51005-V1 User's Guide
Introduction
This user’s guide provides setup and usage instructions for the Car Access Reference System (CARS) featuring
Remote Keyless Entry (RKE), Passive Entry/Passive Start (PEPS), Ultra-Wideband (UWB) distance measurement
and vehicle Immobilizer (IMMO) functionality, based on the Microchip’s GEN2 communication protocols. It offers a
complete car access system for various car access products and its evaluation. The reference designs are both
scalable and configurable through either the PC application or source code modifications, enabling adaptation of
the basic hardware and software building blocks to meet the most recent requirements for specialized systems. For
example, the UWB reference design board is not required if the UWB functionality is not being evaluated.
Features
• Full Car Access System Capability:
– Vehicle IMMO
– Multichannel RF RKE
– LF PEPS
– Identifying relay attack with UWB distance measurement
• Open System Software:
– Open Immobilizer Protocol (OIP) immobilizer stack using AES-128
– RKE RF rolling code using AES-128
– PEPS protocol with a high-precision 3D localization using AES-128
– Scalable and configurable
– PC Graphical User Interface (GUI) for system visualization and viewing data communication
• Body Computer Emulation using the SAMC21J18A XplainedPro (XPRO) Evaluation Board
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User Guide DS50003051B-page 1

Table of Contents
Introduction.....................................................................................................................................................1
Features ........................................................................................................................................................ 1
1. Quick References....................................................................................................................................4
1.1. Reference Documentation............................................................................................................4
1.2. Hardware Prerequisites................................................................................................................4
1.3. Acronyms and Abbreviations........................................................................................................4
2. Kit Overview............................................................................................................................................ 6
2.1. Immobilizer Block......................................................................................................................... 6
2.2. RKE Block.................................................................................................................................... 6
2.3. PEPS Block.................................................................................................................................. 7
2.4. UWB Block................................................................................................................................... 7
3. Kit Setup..................................................................................................................................................8
4. CARS Kit PC Evaluation Utility............................................................................................................. 10
4.1. Programming Kit Software......................................................................................................... 10
4.2. Determining the ATSAMC21-XPRO Virtual COM Port Number.................................................10
4.3. COM Port and Baud Rate Settings.............................................................................................11
4.4. Initial Configuration of the CARS Kit PC Evaluation Utility ........................................................ 11
5. System Operation................................................................................................................................. 13
5.1. Immobilizer Operation................................................................................................................ 13
5.2. Remote Keyless Entry Operation............................................................................................... 14
5.2.1. RKE Operation.............................................................................................................14
5.3. PEPS Operation......................................................................................................................... 15
5.3.1. System Configuration Window Overview.....................................................................16
5.3.2. PEPS Message Status Window Overview...................................................................19
5.3.3. Identifying FOBS within LF Range...............................................................................20
5.3.4. Fob Calibration Overview............................................................................................ 21
5.3.5. Fob Calibration Process ............................................................................................. 22
5.3.6. PEPS Wake-up Functionality.......................................................................................30
5.3.7. PEPS Communication................................................................................................. 31
5.3.8. UWB Communication.................................................................................................. 33
5.4. UWB Operation.......................................................................................................................... 34
6. Programming Instructions..................................................................................................................... 36
6.1. Programming the ATA5702 on the ATAB5702A Fob Board....................................................... 36
6.2. Programming the ATA5831 on the ATA5831-XPRO Board........................................................38
6.3. Programming the SAMC21J18A on the ATSAMC21-XPRO Board........................................... 40
7. XPRO USB Driver Installation...............................................................................................................43
8. Document Revision History...................................................................................................................44
The Microchip Website.................................................................................................................................45
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Product Change Notification Service............................................................................................................45
Customer Support........................................................................................................................................ 45
Microchip Devices Code Protection Feature................................................................................................ 45
Legal Notice................................................................................................................................................. 45
Trademarks.................................................................................................................................................. 46
Quality Management System....................................................................................................................... 47
Worldwide Sales and Service.......................................................................................................................48
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1. Quick References
1.1 Reference Documentation
For further details, refer to the following:
•ATAN0088 Open Source Immobilizer Protocol Stack Application Note (9195)
•ATAN0074 Microchip Passive Entry/Passive Start System Application Note
•ATAN0014 RF System Architecture Considerations Application Note (9256)
•AVR411: Secure Rolling Code Algorithm for Wireless Link Application Note (2600)
•AN3523: ATA5350 UWB Transceiver Security Considerations Application Note (DS00003523)
1.2 Hardware Prerequisites
• Vehicle-side boards
– One ATSAMC21-XPRO microcontroller board
– One ATA5291-XPRO or ATA5293-XPRO LF coil driver with built-in immobilizer base station board
• ATA5291-XPRO: One ATAB-LFTX-V4.0 LF antenna module (can be configured as an inductive load
needed for the immobilizer)
• ATA5293-XPRO: One X-10013-002 antenna. One X-10013-003 antenna (optional)
– One ATA5831-XPRO RF transceiver board
– One ATA8352 XPRO UWB transceiver board (optional)
• Fob and transponder
– One ATAB5702A-V2.3B RF transmitter with 3D LF PEPS and 3D LF immobilizer transponder board
– One ATA8352-XPRO UWB transceiver board (optional)
• Other accessories
– One Ultra High Frequency (UHF) Sub-Miniature A (SMA) whip antenna (included with ATA5831-XPRO
board)
– One USB cable
– One DC plug to banana plugs adapter cable (included with the ATA5291-XPRO board)
– Two UWB PCB antennas (optional)
Note: The ATAB5702A fob board requires a CR2032 lithium battery for operation, which is not provided.
1.3 Acronyms and Abbreviations
Table 1-1. Acronyms and Abbreviations
Acronyms and Abbreviations Description
CARS Car Access Reference System
CSV Comma Separated Variable
EOL End-of-Line
GUI Graphical User Interface
IMMO Immobilizer
MAC Message Authentication Code
OIP Open Immobilizer Protocol
PEPS Passive Entry/Passive Start
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Quick References
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...........continued
Acronyms and Abbreviations Description
RKE Remote Keyless Entry
SMA Sub-Miniature A
ToF Time of Flight
UA Unidirectional Authentication
UID Unique ID
UWB Ultra-Wideband
UHF Ultra High Frequency
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Quick References
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User Guide DS50003051B-page 5

2. Kit Overview
This section describes the different blocks supported by the CARS.
Figure 2-1. CARS System Block Diagram
Main
Controller
Board
(SAMC21)
(ATA5702)
3D LF PEPS
and
3D LF
Transponder
LF Link
(125kHz)
LF Immobilizer Link
(125kHz)
Fob Vehicle
SPI
UWB Verifier
(ATA8352)
SPI
UWB Prover
(ATA8352)
UWB Link
(6520 MHz)
UHF Link
(433.92 MHz)
RF Transmitter
RF Receiver
(ATA5831)
Immobilizer
Basestation and
LF Coil Driver
(ATA5291/3)
SPI
SPI
2.1 Immobilizer Block
The immobilizer is considered the system foundation because it must always work, even if the fob battery is dead,
and secures a vehicle against unauthorized engine starts. It consists of a base station, placed in the vehicle, that
provides the LF (125 kHz) magnetic field enabling a wireless link with the transponder in the fob to be established.
This LF immobilizer link is used to exchange the power supply and digital data between the vehicle and the passive
transponder.
The implemented immobilizer system supports Microchip’s OIP, which consists of an open/unlicensed protocol stack
based on AES-128 encryption. First, the ReadUID command is sent to the fob. The fob has to decode the ReadUID
command and respond with its Unique ID (UID) value. If the received UID value is correct (matches the stored UID),
the start authentication command is issued and challenge data is sent to the fob based on the authentication type
(unilateral or bilateral). The fob receives the challenge, performs the encryption and sends a ciphered response back.
This response is received by the base station and verified to complete the authentication process.
Notes:
1. The fob is a receive-only device; therefore, the ciphered response back to the base station is accomplished by
loading/unloading the magnetic field to encode the data.
2. For more details on the OIP protocol, refer to the ATAN0088 Open Source Immobilizer Protocol Stack
Application Note (9195).
2.2 RKE Block
RKE functionality provides the means to lock or unlock and even start the vehicle from a long distance with a fob
carried by the user. The system consists of an RF receiver in the vehicle and an RF transmitter in the fob. Unlike the
immobilizer operation, the RKE operation requires a battery (CR2032 or equivalent) to be inserted in the fob.
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The implemented RKE system supports Microchip messaging protocol (AVR411), which consists of a unidirectional
UHF link that is secured based on an AES-128 rolling code algorithm. The message contains information that is used
to verify the identity and authenticity of the user and the intended action (command code).
Note: RF and UHF are used interchangeably in this document. For more details on the RKE protocol, refer to the
AVR411: Secure Rolling Code Algorithm for Wireless Link Application Note.
2.3 PEPS Block
PEPS functionality provides the user with a means to lock/unlock and start a vehicle just by having the electronic
fob with them, without the need to actively interact with it. It consists of an LF coil driver placed in the vehicle, which
generates a strong magnetic field on multiple (optional) LF PEPS antennas.
The passive fob implemented in the PEPS system can wake up on this LF field and receive the incoming data via
the unidirectional LF link. The fob also measures the strength of the magnetic field, which is used to determine the
position of the fob relative to the vehicle (outside or inside). Then, it encrypts the received challenge data (using AES)
and returns the correct cipher response, together with the positioning information, to the vehicle via the unidirectional
UHF link.
Note: For more details on the PEPS protocol, refer to the ATAN0074 Microchip Passive Entry/Passive Start System
Application Note.
2.4 UWB Block
UWB functionality provides the means to detect if a relay attack is occurring between the vehicle and fob by
performing a Time of Flight (ToF) distance measurement during every PEPS operation.
A relay attack is detected when the vehicle initiates a PEPS command, such as lock, start and more, which wakes
up the fob via the LF link. After receiving the LF data, the fob, which is configured as a UWB verifier, initiates the
ToF distance measurement with the vehicle, which is configured as a UWB prover. After the vehicle responds to the
fob using the UWB link, the fob performs the ToF distance measurement. If the measured distance, sent within the
PEPS message to the vehicle via the unidirectional UHF link, is beyond the configured distance threshold, then a
relay attack error message displays within the GUI. The same is true if there is no UWB message response from the
fob.
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3. Kit Setup
Perform the following steps to set up the ATAK51005-V1 kit:
1. On the ATSAMC21-XPRO microcontroller board, ensure that the VCC-SEL jumper is set to the 5.0V position.
2. If using the ATA5291-XPRO board, perform the following actions; otherwise, skip to step 3.
– Insert the ATA5291-XPRO LF coil driver/immobilizer board in the EXT3 connector on the ATSAMC21-
XPRO board.
– Connect the ATAB-LFTX LF antenna module to Ant0 on the ATA5291-XPRO board.
– Ensure that the J1 jumper on the LF antenna module is set to the inductor only ( ) position, and go
to step 4.
Note: For use of the antenna on the Ant1-7 connectors, ensure that the jumper on the LF antenna
module is set to the LCR position.
3. If using the ATA5293-XPRO, perform the following actions:
– Insert the ATA5293-XPRO LF coil driver/immobilizer board in the EXT3 connector on the ATSAMC21-
XPRO board.
– Connect the X-10013-002 antenna to Ant0 on the ATA5293-XPRO board.
Note: For use of the Ant1-5 and 8 connectors, the X-10013-003 antenna is required.
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Kit Setup
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Figure 3-1. ATAK51005-V1 Kit Setup
ATA5291-XPRO Board
ATSAMC21-XPRO Board
ATA5831-XPRO Board
ATAB-LFTX LF Antenna Module
UHF SMA Whip Antenna
ATAB5702A Fob Board
4. Insert the ATA5831-XPRO RF transceiver board in the EXT1 connector on the ATSAMC21-XPRO board.
5. Connect the UHF SMA whip antenna to the ATA5831-XPRO board at the ANT2 SMA connector.
6. If UWB functionality is being evaluated, perform the following actions; otherwise, skip to step 7.
– Insert the ATA8352-XPRO UWB transceiver board in the EXT2 connector on the ATSAMC21-XPRO
board.
– Connect the UWB PCB antenna to the ATA8352-XPRO board.
– Connect the UWB board to the EXT2 connector on ATAB5702A fob board.
– Connect the UWB PCB antenna to the UWB XPRO board.
7. Connect the 12V DC power supply to the power socket (J11) on the ATA5291-XPRO board using the DC plug
adapter cable.
Notes:
• Always unplug the adapter cable and the USB cable prior to inserting or removing any boards within the system.
• Always remove the battery from the fob board prior to inserting or removing any boards.
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Kit Setup
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4. CARS Kit PC Evaluation Utility
This section describes the programming and configuration settings for using the CARS kit PC evaluation utility.
Note: The latest version of the utility is available for download at www.microchip.com/developmenttools/
ProductDetails/ATAK51005-V1.
4.1 Programming Kit Software
Program all the individual boards that comprise the kit prior to use. For more details, refer to 6. Programming
Instructions.
4.2 Determining the ATSAMC21-XPRO Virtual COM Port Number
The system software consists of a CARS kit PC evaluation utility, which runs on a host PC and communicates with
the ATSAMC21-XPRO board via the virtual COM port. Install the USB driver (Windows 10 and later) to support the
ATSAMC21-XPRO virtual COM port via a USB connection (see 7. XPRO USB Driver Installation).
Perform the following steps for determining the ATSAMC21-XPRO virtual COM port number:
1. Connect the micro-USB plug to the USB connector on the ATSAMC21-XPRO board.
2. Connect the other end of the USB cable to an open USB port on the PC. Open the Windows Device Manager
on the PC.
3. Expand the “Ports (COM & LPT)” menu, then note the COM port assigned to the “EDBG Virtual COM Port”.
In this example, COM17 is used while connecting the CARS kit evaluation utility program to the ATSAMC21-
XPRO board.
Figure 4-1. Virtual COM Port Assignment
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Note: Always ensure that the adapter cable and the USB cable are unplugged prior to inserting or removing any
boards within the system.
4.3 COM Port and Baud Rate Settings
Navigate to the folder containing the downloaded ATAK51005-V1 software files and open the
CARS_PC_Application.exe file. Perform the following steps for the COM port and baud rate settings.
COM Port Settings
In the Car Access System PC Application window, navigate to COM > PORTs > COM17.
Figure 4-2. COM Port Selection
Baud Rate Settings
In the Car Access System PC Application window, navigate to COM > BAUD Rate > 115200.
Figure 4-3. Baud Rate selection
The CARS utility is now ready for use.
4.4 Initial Configuration of the CARS Kit PC Evaluation Utility
Perform the following steps for configuring the CARS kit:
1. In the Car Access System PC Application window, navigate to View > System Configuration.
2. Click on the refresh icon to update the system’s firmware version and other variables. The system software
version loads correctly if the connection is valid (COM port is open).
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Figure 4-4. System Configuration Window
3. Place the ATAB5702A fob board in close proximity (<10 cm) to the LF antenna module (see the following
figure).
Note: The ATAB5702A fob board placement is similar on the X-10013-002 antenna.
Figure 4-5. Fob Placement
4. Click the LF Learn button in the System Configuration window.
5. The fob UID in the “Learned Fobs” section indicates the successful completion of the learn procedure.
6. If the learn procedure is unsuccessful, repeat step 4 a couple of times. If it still fails, try moving the ATAB5702A
fob board position slightly on the LF antenna module or X-10013-002 antenna and repeat step 4.
Notes:
• The learn procedure is required for the system to function properly, during which, the fob and the base station
exchange the UID and secret keys. The fob UID value is stored in the ATSAMC21-XPRO non-volatile memory
upon completion of this procedure.
• Do not click the Clear button in the System Configuration window as doing so erases all stored UID values.
Without the stored values, the system car access functions, PEPS authentication and RKE messaging do not
operate.
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5. System Operation
The system includes the following features:
• Immobilizer functionality:
– Supports OIP
– Support for AES-128 encryption
– Passive fob authentication supporting Unidirectional Authentication (UA)
– Support for base station to transponder key learn sequence used during the learning procedure
– Support for several utility immobilizer commands (such as communication or transponder data
management)
• RKE functionality:
– Support for unidirectional AES based rolling code protocol
– Use of multiple channel UHF messaging provides robustness against the effects of multipath or in-band
interference
• PEPS wake-up functions:
– Selectable LF driver coil
– Selectable LF driver current (ICOIL = 50 mA to 1000 mA)
– LF driver polling support
– Configurable preamble and header settings for LF wake-up via source code updates
– Unidirectional UHF data return channel included
• UWB functions:
– ToF distance measurement is performed with every PEPS command sent from the vehicle to the fob
– Relay attack notification provided in every PEPS response
5.1 Immobilizer Operation
The immobilizer functionality is tested using the base station hardware (ATSAMC21-XPRO/ATA5291-XPRO or
ATA5293-XPRO/LF antenna module or X-10013-002 antenna) and the ATAB5702A fob board. The CARS PC
application displays the UID, challenge, response and result of the authentication in the Immobilizer Status window
each time the authentication command is executed. Perform the following steps to test the immobilizer using the
CARS PC application running on the host PC:
1. If not done so already, follow the procedure detailed in 4. CARS Kit PC Evaluation Utility.
2. Navigate to View > Immobilizer. The Immobilizer Status window shows the following data fields:
Figure 5-1. Immobilizer Status Window
– “Immobilizer UID” – Displays the unique ID value received from the fob
– “Immobilizer Challenge” – Displays the most current challenge data sent to the fob
– “Immobilizer Response” – Displays the most current response data received from the fob
– “Immobilizer Result” – Displays the authentication status
– “Log file” – Selecting this check box creates a new record line in a Comma Separated Variable (CSV)
document for each received message when it is selected
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3. Place the fob near the LF antenna module or X-10013-002 antenna within a short distance (<10 cm).
4. Click the Read UID button to execute the ReadUID command. The ReadUID command is sent to the fob and
the fob responds by sending its UID.
Note: This command works even for fobs not learned by the system.
5. Click the Start Authentication button to execute fob authentication. The green shield icon ( ) indicates the
immobilizer status upon successful execution of the start authentication command.
Note: The “Immobilizer Challenge” and the “Immobilizer Response” values are different each time a new
authentication sequence is executed because the “Immobilizer Challenge” is a random number. The UID value
is fixed every time.
6. To test passive operation, remove the battery from the fob and repeat steps 3 through 5.
5.2 Remote Keyless Entry Operation
The RKE functionality is tested using the base station hardware (ATSAMC21-XPRO/ATA5831-XPRO) and the
ATAB5702A fob board. The RKE functionality can be observed using the RKE Message Status window. On the fob,
all three buttons provide RKE command messages. Each button also has two types of press actions – short press
and long press, with each type handled differently. The following table shows how these are currently configured.
Table 5-1. Fob Push Buttons Functionality
Button Action SW1 SW2 SW3
Short press Lock Unlock driver door Open trunk
Long press Remote start Unlock all doors Close trunk
Except for a long press of SW1, all of the other buttons transmit the RKE command messages using FSK modulation
at 9.6 kbps. To carry out a long-range remote start function, a long press of SW1 changes to ASK modulation at 1
kbps. The remote start function command reduces the transmitted data rate. The decrease in data rate enhances
the RF sensitivity of the RF transceiver board, which increases the range. The transmitting and receiving devices are
seamlessly changed, demonstrating their power and flexibility.
For high-quality performance, even in the presence of noise, each button press sends three RKE messages
sequentially on three different UHF channels, referred to as Time and Frequency Domain Redundancy. Thus, it
increases the probability of successful reception of at least one of the messages.
Note: For more details on the RF protocol, refer to the AVR411: Secure Rolling Code Algorithm for Wireless Link
Application Note. For more details on time and frequency domain redundancy, refer to the ATAN0014 RF System
Architecture Considerations Application Note.
5.2.1 RKE Operation
Once one or more fobs are paired with the system, test the RKE using the CARS PC application running on the host
PC as follows:
1. If not done so already, follow the procedure detailed in 4. CARS Kit PC Evaluation Utility.
2. Navigate to View > RKE Messaging. The RKE Message Status window shows the following data fields:
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System Operation
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Figure 5-2. RKE Message Status Window
– “RF Message S/N” – Displays the UID returned by the fob. The same UID value for a given fob displays in
the learned fobs section of the System Configuration window.
– “Log File” – Selecting this check box creates a new record line in a CSV document for each received
message when it is selected.
– “RF Message Counter” – Displays the rolling code message counter value sent to the vehicle. This value
is incremented for every key push. All RKE commands increment the counter value. The counter is
checked against a window of valid counts on the vehicle side to prevent recording and replaying of past
RKE messages from being accepted as valid, which is commonly referred to as a replay attack.
– “RF Message Command” – Displays the most recent RKE command received from the fob.
– “RF Message MAC” – Displays the received 4-byte (32-bit) Message Authentication Code (MAC).
– “RF Message Result” – Displays the result of the comparison between the expected MAC (computed
using AES-128) and the received MAC.
– “RF Channel” – Displays the RF channel that received the message.
– “RF RSSI” – The signal strength measured at the RF transceiver board displays in three formats. There is
a decimal representation read directly from the RF transceiver device followed by a calculated dBm value.
Finally, there is a bar graph that provides visual representation.
3. Press any of the RKE buttons to send the RKE message. For more details, refer to 5.2. Remote Keyless Entry
Operation.
5.3 PEPS Operation
The PEPS functionality is tested using the base station hardware (ATSAMC21-XPRO/ATA5831-XPRO/ATA5291-
XPRO or ATA5293-XPRO/LF antenna module or X-10013-002 antenna/ATA8352-XPRO) and the ATAB5702A fob
board with ATA8352-XPRO board. The PEPS operation is commanded by the CARS PC application to send LF
wake-up messages along with UWB messages to the fob, which, then, responds with information via the UHF and
UWB link.
Note: UWB boards are not required for PEPS Operation.
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Figure 5-3. PEPS Start Procedure
Fob RF TX
GUI
Vehicle Main
Controller Board
Vehicle LF
Coil Driver
Vehicle RF RX
Vehicle
UWB Prover
Fob
Microcontroller Fob LF PEPS
Fob UWB
Verifier
5. Transmit LF Pattern Including Wakeup, Challenge for
Authentication and Carrier Wave for Localization
6. Authenticate the Vehicle
and Measure the LF RSSI
8. Prover waits for a Finite Amount of Time
1. USB PEPS
Command 2. Initialization
3. Configure UHF for Polling
4. Configure UWB as Prover
7. Send a Pulse Measurement Request to Vehicle UWB Prover
9. Send Pulse Distance Measurement from Prover to Verifier
10. After Prover's Response the UWB
Data is used to Calculate the ToF
Measurement
13. Process the Received
PEPS Information
14. Send the PEPS
Information to
GUI via USB
12. Respond to Vehicle via UHF with UWB ToF and LF RSSI Distance Measurement
11. Set an RF Frame with UWB ToF and
LF RSSI Distance Measurement
5.3.1 System Configuration Window Overview
The System Configuration window has the following functions:
• Displays specific software information
• Reports the status of the learned fobs
• Selects the PEPS authentication method
• Set the threshold values for inside/outside detection and relay attack
• Selects a PEPS fob to perform testing
• To set the calibration values and provide an interface to read/write user data in each selected fob
In the Car Access System PC Application window, navigate to View > System Configuration to open the System
Configuration window (see the following figure).
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Figure 5-4. System Configuration Window
The System Configuration window contains the following sections and associated data fields:
• “LF Antennas” – This section includes controls used to select the antenna channel, the current and associated
vehicle ID.
– “Antenna Channel” – Selecting any of these radio buttons assigns which antenna channel is used to send
the LF message from the vehicle. The Ant connector number on the board starts at Ant0 while the antenna
channel displayed on the CARS PC application starts with antenna channel 1. As a result, antenna channel
1 on the PC application corresponds with Ant0 on the board. This offset count continues for all six antenna
channels.
Notes:
• When using the ATA5291-XPRO and antenna channel 1, ensure that the J1 jumper on the LF antenna
module is set to the inductor only ( ) position. When channels 2 through 6 are used, ensure the
J1 jumper on the LF antenna module is set to the LCR option.
• When using the ATA5293-XPRO and antenna channel 1, the X-10013-002 antenna is required. When
antenna channels 2 through 5 are used, the X-10013-003 antenna is required; channel 6 is not used
within the PC application.
– “Antenna Current” – This drop-down list determines the amount of current flowing in the LF antenna
during the LF message. This is directly related to the field strength at a given distance from the antenna.
Therefore, any change to this value has a direct impact on the performance of the localization during
PEPS.
– “Vehicle ID” – Sets the wake-up value transmitted with the LF message. Only fobs that are looking for
this value wake up and respond. The vehicle ID is set in the fob during the learn procedure and is
user-definable.
• “Learned Fobs” – This section lists up to four individual fob IDs paired with the system and saved in memory.
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– “LF Learn” – This button performs the initial pairing of any new fobs to the system using the immobilizer LF
field provided by the LF antenna. For details on the learn procedure, see 4.4. Initial Configuration of the
CARS Kit PC Evaluation Utility .
– “Clear” – This button erases all the saved fob secret keys and configuration data from the system memory.
Note: The system does not have full functionality until a fob is paired.
• “PEPS Features” – This section includes configuration settings that affect PEPS messaging functions, including
the type of authentication during polling, as well as, a polling interval.
– “Unilateral and Bilateral Authentication” – Selecting either of these radio buttons has an effect on the type
of communication used during polling only.
– “Polling”– Range checking and the determination of a desired threshold performance can easily be done
with polling. Selecting this check box starts the polling cycle, which repeats at a rate set in milliseconds.
Note: 500 ms is the minimum allowable value.
– “In/Out Threshold” – Determines if a fob is inside or outside of the vehicle by comparing the distance scale
result against the in/out threshold value. The boundary value is user-definable and can be specified by
entering a new value (1-599) in this field.
– “Relay Attack Threshold” – Determines if a fob is inside or outside of the vehicle by comparing the
UWB distance measurement result against the Relay Attack threshold value. The boundary value is user-
definable and can be specified by entering a new decimal value (1-100) in this field.
– “Priority Fob” – This drop-down list allows users to specify which fob is given priority when responding to a
PEPS command following the common slot of the anti-collision process.
• “PEPS Fob Actions” – This section allows for selection and communication with an individual fob even with other
PEPS fobs present.
– “Selected Fob” – This drop-down list allows direct access to an individual fob. Selecting Broadcast allows
communication with any fob, even unlearned ones. This facilitates accessing a fob ID even if the vehicle ID
for that specific fob is unknown.
Figure 5-5. Selected Fob – Broadcast
– “Fob ID” – This button provides a way to access the current fob ID, the vehicle ID and the battery status.
– “S/W Ver” – This button requests the current fob software version.
– “Low Bat” – This check box is selected by the software if the battery voltage in the current fob is below the
low battery threshold (approximately 2.6V).
– “Fob Vehicle ID” – Displays the vehicle ID stored within the current fob.
– “LF Test” – This tab displays all the details relating to a test LF field measurement. Details such as
the external, internal RSSI values and coil phase clock counts display here. The distance scale value is
determined by the combined result of all post-RSSI processing. In a standard PEPS message, the distance
scale and the coil phase values are sent.
– “Parameter Access” – This tab displays general user memory sections of the fob EEPROM that can be
accessed via the PEPS system link. These are configured into 32 blocks of memory with each block having
16 bytes of data available. The data can be displayed in HEX or ASCII format. To access the memory, the
fob must first be put into a password-protected Diagnostic mode by clicking the Enter Diag button. Then,
for several seconds, the fob responds to read or write commands.
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System Operation
© 2020-2022 Microchip Technology Inc.
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User Guide DS50003051B-page 18

Figure 5-6. Parameter Access
– “Calibrate Fob” – This button initiates a calibration cycle, which provides reference values as each fob LF
antenna coil axis has slightly different gains due to the antenna coil, capacitor and IC tolerances. This is
typically done at the end-of-line testing by the manufacturer and is necessary to achieve consistent results.
It only needs to be performed once for each fob. For details on the calibration procedure, see 5.3.4. Fob
Calibration Overview.
5.3.2 PEPS Message Status Window Overview
The PEPS Message Status window displays the challenge or response information along with localization details
and ToF measurement performed using UWB for each fob that is learned to the system. In the Car Access System
PC Application window, navigate to View > PEPS Messaging to open the PEPS Message Status window (see the
following figure).
Figure 5-7. PEPS Message Status Window
The PEPS Message Status window contains the PEPS commands section and shows the following data fields:
• “Serial Number” – Displays the received fob ID. This must correspond to the value in the Learned Fobs section
of the System Configuration window.
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User Guide DS50003051B-page 19

• “LF Challenge” – Displays the 4-byte LF challenge data that was sent to the fob. This challenge data is sent
during bilateral and unilateral authentication.
• “LF Encrypted Challenge” – Displays the 4-byte LF encrypted data sent to the fob during bilateral authentication
only.
• “RF MAC” – Displays the received RF MAC value from the fob.
• “Localization” – Displays the current localization status of the current fob (for example, inside or outside the
vehicle). This is determined by comparing the distance scale value against the “In/Out Threshold (RSSI)” value
displayed in the System Configuration window (see Figure 5-4).
Note: The fob section is highlighted in blue if the fob is found “inside” and pink if the fob is found “outside.” This
allows for an easy determination from a distance while the range of the system is being tested.
• “Distance Scale” – Indicates the RSSI scale value received.
• “Coil Phase Signature” – Displays a three-digit binary code (see the following table):
•Table 5-2. Coil Phase Signature Calculation
Bit
Position
Calculation Using Coil Phase Clock
Count Values
Bit Value (If 90° < Calculated Result
< 270°)
Bit Value
(Otherwise)
1Z − Y value
360 value x360 1 0
2Z − X value
360 value x360 1 0
3Y − X value
360 value x360 1 0
Note: The Z-Y, Z-X, Y-X and 360 coil phase clock count values are found in the “PEPS Fob Actions” section of
the System Configuration window.
• “TOF Measured (cm)” – Displays the Time of Flight measured between the vehicle and the fob.
Notes:
• The Relay Attack icon appears when both ATA8352-XPRO boards are connected and the “TOF Measured
(cm)” value is greater than the “Relay Attack Threshold (cm)” value or if the fob does not return a measured
value.
• The Battery Low icon appears if the fob returns a low voltage warning indicating the battery voltage is
below 2.6V (approximately).
• “Log PEPS transaction to file ” – Selecting this check box creates a new record line in a CSV document for each
received message when it is selected.
• “PEPS Commands” – This section includes controls for initiating various PEPS functions and their associated
authentication used.
– “Start/Stop” – This button initiates either the start or stop PEPS function depending on the status of the
vehicle.
– “Unlock” – This button initiates the unlock PEPS function.
– “Lock” – This button initiates the lock PEPS function.
– “Unilateral and Bilateral Authentication” – Selecting either of these radio buttons has an effect on the type
of communication used during the selected PEPS commands.
5.3.3 Identifying FOBS within LF Range
Identify the available fobs by sending out a broadcast, which returns the Fob# in the selected fob field. Perform the
following steps to identify the available fobs within the LF range:
1. If not done already, follow the procedure detailed in 4. CARS Kit PC Evaluation Utility.
2. In the System Configuration window, choose Broadcast from the “Selected Fob” drop-down list (see Figure
5-5).
3. Click the Fob ID button to send the broadcast request. The available fobs respond with their fob IDs and their
Fob# assignments. The “Fob Vehicle ID” field displays the returned vehicle ID.
4. Click the S/W Ver button to send the software version request to the fob. The “S/W Ver” field displays the
returned software version number.
ATAN0219
System Operation
© 2020-2022 Microchip Technology Inc.
and its subsidiaries
User Guide DS50003051B-page 20