When using ISE 9.1i on a Virtex-5 design, the IOBDELAY attribute, I receive the following warning:
WARNING:NgdBuild:486 - Attribute "IOBDELAY" is not allowed on symbol
"mpu_addr(2)" of type "IPAD". This attribute will be ignored.
Why am I not allowed to add this attribute?
This warning can be safely ignored because the constraint is still being applied. This is a known issue and will be fixed in ISE version 9.2i SP1.