PEPS Demo PKE/PKG Function Implementation

I. Overview

        Some time ago, the author shared the " Keyless entry Solution Based on SemiDrive E3210 & NXP NJJ29C2 & NCK2911 & NCF29A1 PEPS" in the Solution knowledge Base area 》，. The solution includes a base station master control board based on SemiDrive E3210, a low-frequency driver board based on NXP NJJ29C2, a high-frequency receiver board based on NXP NCK2911, and a high-frequency receiver board based on NXP. NCF29A1 key board.

       Today's article is based on this scheme to share with you the implementation process and function display of the PKE/PKG function in the Demo.

Second, the application scenario

1. PKE/PKG communication process

        PKE (Passive Keyless Entry), that is, the function of unlocking the door at close range. PKG (Passive Keyless Go) is the one-click start function in the car. The PKE/PKG communication process includes the low-frequency transmission of a low-frequency signal by the base station to the key, and the return of a high-frequency signal to the high-frequency module of the base station for reception after the key is awakened, as shown in the figure below.  

Figure 1 PKE/PKG communication

2. Introduction to application scenarios

        ①PKE function

        In the demo of this function, it is triggered by the high level of the test point, which simulates the actual vehicle pulling the car door handle to trigger (no need to control the key button). The base station master commands the low-frequency board to send an RSSI measurement command, after which the key starts RSSI detection, and then the test result is returned through UHF, which is judged by the base station master.The key is inside the car and outside. If it is outside the car, HT-3 certification will begin, and the door will be unlocked if the certification is passed.

        ②KG function

        This function is similar to PKE. The function is triggered by a button in the demo, which simulates that when the driver presses the “one-button start” button in the actual vehicle, the RSSI detection will be triggered, but only when the key is in the car, the HT-3 authentication will start, and the engine can only be started after the authentication is passed; otherwise, the engine is still in use.In a locked state.

Third, the implementation process

1. PKE function

        When performing the PKE function, after the key completes the RSSI detection and return, if the base station determines that it is outside the car and the authentication is passed, the door is unlocked. The PKE function flow is shown in the figure below. The RSSI value judgment is only a reference value and needs to be adjusted according to the actual situation.

Figure 2 PKE function implementation process

2. PKG function

        When performing the PKG function, after the key completes the RSSI detection and return, if the base station determines that it is in the car, the HT-3 authentication will start, and the engine can only be started after the authentication is passed; otherwise, the engine is still in a locked state.

        If the key is not awakened and the base station cannot receive the returned data, it is determined that the key may be out of power and the IMMO function is activated for authentication. At this time, the key needs to be placed close to the IMMO antenna. If the received key ID is correct and the HT-3 authentication result is met, the engine can be started.

Figure 3 PKG function implementation process

Fourth, the function display

1. As shown in the figure below, the hardware construction is completed, and the antenna layout is described as follows：

        There are a total of 9 sets of antennas available for NJJ29C2. The antenna channels used by the PKE/PKG function are described as follows：

         (1) TX1 + TX2, using a high-power drive mode (the maximum current can be increased to 2.5 A), is used to send PKE/PKG RSSI measurement commands to detect the position of the key relative to the antenna.

         (2) TX3, used for PKE HT-3 certification.

         (3) TX6, used for PKG HT-3 certification.

Figure 4 Hardware connection diagram

2. PKE

        Trigger the E5 high level at the expansion port (equivalent to pulling the door handle), TX1+TX2 sends an RSSI measurement command and a constant carrier signal, and the base station determines whether the key is in the car or outside the car based on the RSSI value measured by the key.

Figure 5 Expansion port E5 high-level trigger

        If the key is outside the car, TX3 will start HT-3 authentication. If the authentication is passed, the door will open, and the OLED display information is shown in the figure below.

Figure 6 is verified and the door is opened (the distance is for reference only)

        Conversely, if the key is in the car, it will indicate that it is already in the car.

Figure 7 The key is already in the car (the distance is for reference only)

        If the key is not detected, that is, the high-frequency receiving board of the base station has not received the RSSI value measured by the key, the user will be prompted to try again.

Figure 8 The key is not detected

3. PKG

        Press the user button SW5 (equivalent to pressing the “one-key start” button), TX1+TX2 sends an RSSI measurement command and a constant carrier signal, and the base station determines whether the key is in the car or outside the car based on the RSSI value measured by the key.

Figure 9 User button SW5

        If the key is in the car, TX6 will start HT-3 authentication. If the authentication is passed, the engine will start, and the OLED display information is shown in the figure below.

Figure 10 Engine start (distance is for reference only)

        Conversely, if the key is outside the car, the engine is still locked when the “one-button start” is pressed, as shown in the figure below.

Figure 11 Engine locked (distance is for reference only)

        If the RSSI value measured by the key is not received, IMMO authentication will be activated when the key is out of power.

V. Conclusion

        The above is the entire content of this article . I am interested in the "Keyless Entry Solution based on SemiDrive E3210 & NXP NJJ29C2 & NCK2911 & NCF29A1 PEPS " solution. If you need relevant information, you can click on the link to ask questions and contact us.

6. Reference materials

1. Based on SemiDrive E3210 & NXP NJJ29C2 & NCK2911 & NCF29A1 PEPS keyless entry solution
2. Simple operation manual-T23-017 PEPS Trainer_V1.0 (Xinchi E3210 PEPS software part) _Flora Weng_2024.07.08. pdf