I am attempting to set some of my I/Os to various I/O standards in Constraints Editor for my Virtex-II design, but many of the I/O standards are not listed. How do I select these I/O standards?
To select these, manually edit the UCF, adding the desired I/O standard.
This problem is fixed in the latest 5.1i Service Pack, available at:
The first service pack containing the fix is 5.1i Service Pack 2.