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).

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.
• “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)
  1	$\frac{Z-Yvalue}{360value}x360$	1	0
  2	$\frac{Z-Xvalue}{360value}x360$	1	0
  3	$\frac{Y-Xvalue}{360value}x360$	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.
  Note:

  • 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.