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AR# 55525

MIG 7 Series, Virtex-6 DDR3 - Design not properly configuring the RDIMM control register for voltage and frequency


Version Found: 

7 Series MIG v1.8, Virtex-6 MIG v3.92

Version Resolved: 

Manual Work Around Required for Virtex-6.
See (Xilinx Answer 54025) for MIG 7 Series.

DDR3 RDIMMs include IDT registers that the memory controller must configure during initialization through MRS commands.  

Control word 10 includes the encoding for the RDIMM operating speed. 

Control word 11 includes the encoding for the RDIMM VDD voltage.  

The MIG 7 Series and Virtex-6 designs do not properly program these registers.


To work around this in Virtex-6 MIG, please replace the phy_init.v module with the attached file.

Note: there have been no reports of hardware failures due to the incorrect control register settings used.


Associated Attachments

Name File Size File Type
phy_init.v 121 KB V
AR# 55525
Date Created 04/11/2013
Last Updated 10/24/2014
Status Active
Type Known Issues
  • Artix-7
  • Kintex-7
  • Virtex-7
  • Virtex-6
  • MIG 7 Series
  • MIG Virtex-6 and Spartan-6