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AR# 6201

1.5i Virtex Map - ERROR:xvkdr:41 - blockcheck: Improper DLL feedback loop.


Cases have been seen where the Virtex Mapper incorrectly fails with the error:

ERROR:xvkdr:41 - blockcheck: Improper DLL feedback loop. DLL dll/ext_clk_dll
has an invalid output. Since input pin CLKFB is being driven by a GCLKIOB,
either CLK0 or CLK2X must be used.

This problem only occurrs on PCs in 1.5i.


An FTP Update file is available with will correct this problem in 1.5i Service Pack 2:


CAUTION: This FTP Update is intended as a fast response for the issue
mentioned only. The risk inherent in this fast response is that there
is not enough time or resources available for the full regression testing
that is done for the Service Pack Updates and there is a higher risk of
introducing new problems. It is recommended that customers always install
the latest Service Pack Update, but only install FTP Updates when needed to
resolve specific issues.

NOTE: This FTP Update is only compatible with an A1.5i/F1.5i system that
have Service Pack 2 installed..
AR# 6201
Date Created 04/15/1999
Last Updated 04/10/2000
Status Archive
Type General Article