When I run the EDIF netlist through implementation, the following warning is reported in NGDBuild:
"WARNING:NgdBuild:483 - Attribute "IOBDELAY" on "input1" is on the wrong type of object. Please see the "Attributes, Constraints, and Carry Logic" section of the Libraries Guide for more information on this attribute."
The Libraries Guide states that the IOBDELAY attribute can be applied to any IOB element (pad, buffer, or net); how do I apply this attribute to my IOBs?
To work around this problem, apply the IOBDELAY attribute via the UCF, using the following syntax:
INST input1 IOBDELAY = BOTH;
This issue will be fixed in the next major software release (after 5.1i).