topic Re: TPMS over-the-air software update. in Sensors

TPMS over-the-air software update.

guwenlong_l — Tue, 03 Feb 2026 21:53:18 GMT

I'm working on a TPMS project, The chip used is FXTH87E. I'm debugging the wireless software upgrade, I downloaded embedded software in FXTH87E location, LF/RF BootLoader. I didn't understand the application manual, and I felt that the steps of the project explanation were not detailed enough.

Must the active controller use Kinetis MKW01Z128 MCU? I now have a TPMS maintenance detection device that can send a low-frequency signal of 125k. However, I used CW11.1 to burn TPMS_BtLdr_1 on FXTH87E for debugging, and found no reaction in the debugging interface. Can FXTH87E be activated by 125k low frequency signal?

How to activate FXTH87E with 125k low frequency signal?

One more question, What is the role of cu8BootEntryKey in the TPMS_BtLdr_1 project code? Is this key required between the device sending low frequency signal and FXTH87E receiving low frequency signal?

Re: TPMS over-the-air software update.

TomasVaverka — Wed, 18 Mar 2020 08:03:13 GMT

Hello,

Please find below the answers from our TPMS software engineer.

1. Figure 7 of the Application Note gives a system overview: the TPMS receives LF commands and send RF commands. In our demo, to transmit LF frames and receive RF frames we are using a KW01 board connected to a LF antenna board. The MKW01 software and TPMS software have been developed to work together, they are compatible with each other in terms of LF and RF frame format, timing etc…

In a final application, users will replace the KW01 + LF antenna with their own tools, and will have to update the TPMS software to be compatible with their tool, in terms of frame format, timing etc…

2. All frame formats are described in the document 2018-01-23_BtLdr_Comm_Packets provided in the package.

3. If the LF frame received contains this data then the TPMS enters Bootloader State 1. The transition flow is described in Figure 3 of the Application Note.

I hope it fully clarifies your questions.

Best regards,

Tomas

Re: TPMS over-the-air software update.

anthonyhhfu — Wed, 10 Jun 2020 14:46:55 GMT

hi Tomas,

In your description with replace the KW01 and LF antenna board with their own tools.

1. I am curious about if possible to replace the LF antenna board with HTRC110-based design? if yes, can I have the reference design?

2. in the KW01+LF antenna board, it seems that MCU’s GPIO needs PWM wave generator for 125khz waveform? is that right?

and the SW need to control timing of the each bit time after convert the data bit to manchester code?

thanks for giving me guidance.

Anthony