This is the dynamic ODT write termination used in multiple-RANK designs. For single-component designs, RTT_WR should be disabled.
解决方案
MIG 7 series does not support Dynamic ODT.
The parameter should always be set to "OFF".
(Xilinx Answer 46082) describes a solution for Dynamic ODT support but it is only for "special use of Dynamic ODT supported by Micron".
Revision History 09/24/2014 - Initial Release
Note: The "Version Found" column lists the version the problem was first discovered. The problem also exists in earlier versions, but no specific testing has been performed to verify earlier versions.