When I generate a LogiCORE 1000BASE-X PCS/PMA or SGMII core in ISE, I receive the following error:
This error only appears when the core is generated from within ISE.
If you take the .xco file to Coregen and generate the exact same core, it will not give you an error.
If you have an ISE project that uses this core, you can use the following steps to work around this issue.
1. Generate the 1000basex or sgmii core using Coregen.
2. Copy and paste all of the generated files to your ISE project folder to replace the original core files.
3. Delete the cores .xco file in your ISE project folder