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AR# 10251

3.1i Virtex Map - Map silently trimming all registers whose clock pin is driven by a BUFCF.

Description

Keywords: clock, CLK2X, BUFCF, CLKDLL, trimmed, removed, removes, messages, silently, Aldec

Urgency: Standard

General Description:
A case has been seen in an Aldec design where registers driven by the following clock circuit:

CLKDLL.CLK2X--->BUFCF--->register clock pins

are silently removed by the mapper. No mention is made of the
registers in the removed logic summary of the .mrp file.

Solution

This problem is related to the use of the BUFCF symbol in the
netlist, which is interpreted as "use local interconnect." The packer
incorrectly tries to internalize the register into the DLL and loses the
register in the process.

A workaround is to modify the netlist by changing every occurrence
of the string "BUFCF" to "BUF". No functionality is lost by this change.

This issue is currently being considered for a future service pack fix.
AR# 10251
Date Created 09/29/2000
Last Updated 08/19/2002
Status Archive
Type General Article