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3.1i - Constraints Editor - No I/O Standard available for clock signals
keywords: I/O, IO, standard, clock, signal
For Virtex, Virtex-E, and Spartan-II, the I/O STANDARD options for clocks in the "Ports" tab
field is still not available for clocks in this column.
The work-around is to manually modify the UCF file.
The following is an example of the correct syntax:
NET "my_net" IOSTANDARD = SSTL3_I;
This change is available in the latest 3.1i Service Pack available at:
The first service pack containing the fix is Service Pack 2.