Can't make FXTH87 Low frequency work for interrupt activation

[javierpernia]

Hi everyone, Im working with the FreeScale's FXTH87xx in a TPMS project. But i cant make the Low Frecuency activate the chip through interruption, im trying to do the simples activation through carrier detection. i follow the datasheet and the TPMS_FXTH87_LF_RF_communitacion example with no luck!!! please i need a guide line to make the LFR work!.

I used the Inductor 7.2mH 105Ohm 3% AEC-Q200  Part N. TPL802727-722H as the LF input 

Thanks for any help!!

[TomasVaverka]

Hi Javier,

Here are a few questions to help determine the cause of the problem:

- What do you use to transmit the LF frames? What is the distance between the LF emitter and the FXTH? The two LF antennas (of the emitter and FXTH) should be parallel to each other for a better reception.

- Could you share the code you are using for LF carrier mode (LF initialization…)?

- In the TPMS_FXTH87_LF_RF_communication project, the LF block is configured to work in data mode, not carrier mode. Are you using the project with no modification? What is the frame format of the LF frame sent? The FXTH is expecting the following format (extract from the demo user guide):

Best regards,

Tomas