ADF4110 series?

Hi,
Does anybody used ADF4110 series PLL? if so what is need of Function Latch?
how to program this latch?
In the datasheet it is given that after power on three 24-bit registers should be latched to the PLL
1) Initialisation Latch
2) R Counter Latch
and 3) N Counterlatch.

But where comes this Function latch.
I am interfacing this with microcontroller.I am confused.
Please someone help me and also provide programming sequesnces.

Thanks in advance.

Regards,
Viswanath.

Function latch will set the pre-scalar, current setting mux control etc.
Go through the data sheet for better understanding