Take a look at the FXTH87 Documentation website. First document I would recommend to read is the FXTH870xD data sheet and then the FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide containing details on the in-flash functions, variables and their functionality. All TPMS parts come with factory programmed firmware described in the above mentioned User Guide. You can make calls to these functions but can not do any debugging of these functions, because their source code is not provided. How to interface to these in-flash routines is described in the AN4277 - Interfacing to Freescale’s FXTH87xx In-Flash Firmware Routines Using C-language Constructors.
I would also recommend taking a closer look at the Installing and using CW 10.6 for TPMS applications document, providing step by step instructions on how to install the CW for MCUs v10.6 + FXTH87 Service Pack and program the Starter project that can be found on the FXTH87 Software&Tools website.
I hope it helps.
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