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AR# 18343

Virtex-II Pro DCM - DCM does not lock when the CLK2X output is used as a FEEDBACK clock to DCM


When my Virtex-II Pro design uses the CLK2X output as the FEEDBACK clock for the DCM, the LOCKED output goes Low and the DCM stops operating correctly (designs that use the CLK2X output but do not use it as a FEEDBACK clock to DCM are not affected).


The CLK2X feedback is not supported in Virtex-II Pro devices. Only the 1X feedback (using CLK0) is supported.

For more information about DCM attributes and functionality, please refer to Virtex-II Pro User Guides and Data Sheets:


AR# 18343
Date Created 09/03/2007
Last Updated 12/15/2012
Status Active
Type General Article