We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 34219

Virtex-6 MMCM - Cascaded MMCMs may not work in hardware


In the Virtex-6 FPGA,cascaded MMCMs may not work in hardware. The behavior seen is that the second MMCM in the chain does not lock.


The ISEimplementationsoftware automatically selects the COMPENSATION mode for thecascaded MMCM. In some cases, the software does not set this attribute correctly.The workaround to this issue is to manually set theCOMPENSATIONattribute to CASCADE for the second MMCM in the user design. This issue will be fixed in ISE 12.4 software.
AR# 34219
Date 05/19/2012
Status Active
Type Known Issues
  • Virtex-6 CXT
  • Virtex-6 HXT
  • Virtex-6 LX
  • More
  • Virtex-6 LXT
  • Virtex-6 SXT
  • Less
Page Bookmarked