User's Guide

Table Of Contents

3. Place the fob near the LF antenna module 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 S1 S2 S3

Short press Lock Unlock driver door Open trunk

Long press Remote start Unlock all doors Close trunk

Except for a long press of S1, 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 S1 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, the RKE can be tested 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:

ATAN0219

System Operation

User Guide

DS50003051A-page 14

Microchip Confidential: For Release Only Under Non-Disclosure Agreement (NDA)