NJJ29C2 IMMO selection parameter description

I. Foreword

       The author is recently studying the PEPS (Passive Entry Passive Start) system. The low-frequency board uses WPI ATU's PEPS System Development Kit solution board. The hardware is designed based on the low-frequency driver chip NJJ29C2A9, but the NJJ29C2A9 material is temporarily unavailable, so I am considering using other chips of the NJJ29C2A series instead, and I will follow up next.Everyone shares the description of the IMMO selection parameters of NJJ29C2.

2. Introduction to the chip

       NJJ29C2 is a base station chip with built-in LF driver for keyless entry/start (PKE/PKG). The main features are as follows：

① Built-in 5~9 LF drivers

② 125 kHz LF carrier frequency

双 Dual-mode IMMO

-CaT-IMMO (compatible with NXP's Charge and Talk transponders)

-LM-IMMO (NXP-compatible traditional load modulation transponders)

④ Strong driving ability

⑤The average polling current is low and the power loss is low

       Among them, there are currently 5 models of NJJ29C2A, which are pin compatible, as follows：

       Among them, RX1 and RX2 are the input pins of the IMMO receiver (for NJJ29C2 series chips)；

       For more features, please refer to the sd525920-NJJ29C2A Preliminary Datasheet (2.0) document.

3. Hardware description

        WPI ATU's PEPS System Development Kit solution board is designed with reference to NXP's original NJJ29C2A9. TX5/RX2 is used for CaT-IMMO, and TX9/RX1 is reserved for LM-IMMO. The details are as follows：

       For this program board, ATU has a relevant demo program that can be used. The author needs to use LM-IMMO. There is no NJJ29C2A9 (TX1~TX9) material in his hand. At present, there are NJJ29C2A6 (TX1~TX6) material, but NJJ29C2A6 does not have TX9, so consider changing the low-frequency control command in the program demo to modify LM-IMMO antenna configuration changed from TX9/RX1 to TX5/RX2.

4. Description of IMMO selection parameters

       For detailed parameter configuration of LM IMMO, please refer to the S32K144 LM IMMO Configuration article. This article only introduces the selection parameters of IMMO. We need to pay attention to the IMMOTXRXPAR part of the CMD_START_IMMO command of LM IMMO Configuration. The IMMO Configuration process is as follows：


        Check the IMMOTXRXPAR section of the user manual for specific instructions as follows：

       The LM-IMMO antenna configuration is configured as TX5/RX2, that is, IMMOTXRXPAR is written as 0x43. The Demo code needs to be modified as follows：

       After burning the program, connect to the antenna, and place the key near the IMMO antenna for verification. As shown in the figure below, you can see the IMMO HT3 PASS, indicating that the channel switching is successful. NJJ29C2 series chips with hardware support, RX1 and RX2 can be configured for LM-IMMO use.

V. Conclusion

       The above is all the content of this blog post. If you need the demo mentioned in the article, you can contact us in the comments area. Thank you for reading.

6. Reference materials

1. sd525920 - NJJ29C2A Preliminary Datasheet (2.0).pdf
2. SCH - P20-010 PEPS System Development Kit_V1.0_Monica Li_2020.06.28.pdf
3. S32K144 LM IMMO Configuration
4. UM525836-NJJ29C2 Product User Manual(3.6).pdf