Documentation for twentynm_iopll

Thanks, @RichardTanSY_Altera.

Yes, you've answered my question. Thanks. And thank you for passing this along to your internal team so they can hopefully improve the documentation.

Having a better understanding the limitations of the IOPLL, I've now achieved my design goals using a different approach. So as far as I'm concerned, we can close the thread.

Thanks again,
-Roee