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AR# 4760

4.1i XC4000E MAP - To control whether a BUFGP or a BUFGS is used, a BUFG must be LOC'd before MAP.

Description

Keyword: BUFG, BUFGP, BUFGS

Urgency: Standard

General Description:
If a BUFG is used in a design but not LOC'd, the mapper could use either a BUFGP or BUFGS site for the clock. Any attempt to add a .pcf file constraint will fail if the site type is not valid for the clock type chosen by MAP.

解决方案

This problem can be avoided by using .ucf constraints, which will guide MAP to select the correct clock type.

Another option is to use BUFGS or BUFGP symbols in the design, rather than a BUFG symbol.
AR# 4760
创建日期 10/06/1998
Last Updated 08/20/2003
状态 Archive
Type 综合文章