Two top-level files called pcim_top.v(.vhd) and pcim_top_r.v(.vhd) are located in the /src/xpci and /example/source directories of the PCI core files. What is the difference between these files and how should they be used?
The pcim_top_r.v(.vhd) file should be used for Virtex-4 PCI core designs. This file contains an input port for the IDELAY controllers used in Virtex-4 designs. This is a 200 Mhz clock input and the port is called JCL. Note that this clock can be generated internal to the design; if this is the case, this port can be removed.
The pcim_top.v(.vhd) file is used for all other non-Virtex-4 PCI core designs.