Wrapping EDK (PPC) system in top level ISE project, ISE 12 and 13
After upgrading to ISE 12.4 on my own machine, and throwing together a quick PPC platform on an underling's machine which has ISE/EDK 13 on it, I have found the following issue:
When I start XPS from "new source -> embedded processor" in my ISE project, and drop the PPC platform into my top ISE file as a component, the "build netlist" in XPS works just fine out of the box, but ISE fails to map the design, because it can't find the netlists for all of the components within the PPC platform. Looking around the forums I found somewhere a VERY OLD post where somebody got the same error I was getting, but on a previous version of ISE, and the solution was to copy all of the .ngc files from system/implementation up to the main ISE project folder.
This fixed my problem, but I believe it means that you have to copy the .ngc files every time you modify something in XPS, which is a huge hassle.
I never had this problem in ISE 10 or 11, it always just worked straight away.
I guess another workaround would be to add the system/implementation folder to the project search path.
But, it would be nice if the issue wasn't there to begin with, as in the previous versions of ISE/EDK.