Hi Raveendra,
I just thought, that if you have a custom board and you going to add some custom hdl, than you want to add support for the new features.
But let's assume, you will use the same (or almost the same) hdl, you don't modify the data path, you don't modify the register map. In that case you can use the no-OS as it is. But once again, if you created a custom board, I presume you want to add some additional feature to the software too.
I would recommend to make sure, that you understand, how to initialize the chip, how to start a transition and/or reception from software, using the AC701+FMCOMMS2, so when your board arrives, you could make your own application easily.
If you have any specific doubts or question let us know.
Thanks,
Istvan