need help mesanet firmware

hello friends 
i want to tailor mesanet fpga firmware for special purpose i know vhdl but i did not understand some portion of code  just need to use spi and pwm analogue servo with encoder and want to delete rest of code .
if there is a document to read about mesanet inner function please share with me or anyone who work with firmware of mesanet fpga and linuxcnc portion of code that relate to mesanet .

thank you 
 

Basically you build custom firmware by changing the pinout file,
including the new pinout file in the project and re-compiling.

All pinout files are named PIN_xxxxxx_N.vhd where N is the total number
of user I/O pins which is FPGA card specific. The easiest way to start is to
take a pinout file that is close to your requirements and modifying it.

Only modules included in the pinout file will be included in the firmware.

you right but i need more detail about module for example why in firm ware mesanet build soft 8 bit cpu and 16 bit cpu and what is d2pll?

A configuration may have several soft CPU's depending on the configuration
for example all Ethernet interfaced cards have a 16 bit soft CPU to handle
Ethernet communications. and may have one or more 8 bit soft CPUs or even
a 32 bit DSP depending on included modules

sir i have not any mesanet interface card just only read from internet and i want to ask question about velocity estimation.i am not expert but i read about PLL and Velocity tracker and some IIR filter what is the advantage of mesanet velocity estimation over tracker or kalman filter and launberger least square method .
i am sure you have mesanet card did you measure velocity accuracy . how commercial CNC like fanuc seimens hidenhien measure velocity ?
and if possible for you please tell me about PID structure of mesasnet closed loop opreration

thank you very much

The low level hardware doesn't do any velocity filtering
but it can be done by LinuxCNC. Quadrature encoder
velocity estimation is done by a counts / time_between_count_timestamps
method

Normally PID is run by LinuxCNC, not the low level hardware