My design ran successfully in ISE version 9.1i but now in 9.2i it fails with the following Logical DRC error. Is this a valid error?
ERROR:LIT:440 - CLKIN of GTP_DUAL symbol "xyz" is not driven by an IBUFDS, IBUFGDS or GT.
The Virtex-5 RocketIO User's Guide (http://www.xilinx.com/xlnx/xweb/xil_publications_index.jsp?category=User+Guides),page 72, shows a clocking scheme called GREFCLK clocking where the CLKIN pin is driven by a BUFG or BUFR. A new Logical DRC check in 9.2i is overly restrictive and incorrectly flags errors on valid configurations where the CLKIN pin is driven by a BUFG or BUFR.
This problem is being evaluated for a future software fix. Meanwhile, this check can be disabled by setting the following environment variable:
Linux and Solaris
setenv XIL_MAP_NO_GT_CLKIN_DRC 1
For general information about setting ISE environment variables, see (Xilinx Answer 11630).