FPM function API you can download here:
Frequency Pulse Measurement (FPM) eTPU Function API
In the package there is an example of usage of FPM function (fpm_example.c and fpm_example.h). I am afraid it is only example we have.
Also I could send you preliminary description (AN2859) from Motorola time (year 2003) - if you want it please create new case (it is „ticket“ for direct contact to technical information center) and I will send it to you:
How to submit a new question for NXP Support
