General Description: When I attempt to use a large Xilinx primitive (such as a PPC403 or GT*) and it fails due to a pin mismatch, NGDBuild reports a vague error message that simply states that the expansion has failed and that the primitive (PPC405 or GT*) is not valid for the target device.
I am using a Virtex-II Pro, so I know the PPC403 or GT* primitive is supported for the target device. What does this error message actually mean?
This error message is misleading, because PPC405 and GT primitives are valid primitives for the target device (Virtex-II Pro). Moreover, the error message also lacks the relevant information needed to fix the problem (the incorrect pin name assignment).
This error message has been fixed and enhanced, beginning with version 4.2i of the software.