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AR# 12208

4.1i Virtex MAP - Registers that are LOC'd to slices end up in IOBs.


Keywords: IOB, slice FF, register, LOC

Urgency: Standard

General Description:
My design contains several flip-flops that are range LOC'ed to a set of slice locations. However, in the NCD file produced by MAP, these flip-flops have been mapped into IOBs rather than slices. No warnings are printed about this, and the .pcf file produced by MAP is empty.


It was found that the flip-flops had IOB=TRUE attributes, which overrode the slice LOCs.

MAP will be changed in the next major release after 4.1i to warn about conflicts between LOC constraints and IOB attributes.
AR# 12208
Date Created 07/30/2001
Last Updated 08/20/2003
Status Archive
Type General Article