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AR# 4974

4.1i 4000E MAP - MAP incorrectly trims OUTFFTs that are permanently active.

Description

Keywords: XNF, OUTFFT trimmed.

Urgency: Standard

General Description:
Pins attached to an OUTFFT with the T tied low (on) in an .xnf file are being trimmed. I cannot simply use OUTFFs, because the design may really be toggling T of OUTFFT.

Solution

You can work around this problem by placing a "nomerge" attribute on the TBUF control net. This can be done in the .ucf file:

NET "netname" KEEP ;
AR# 4974
Date Created 11/04/1998
Last Updated 08/20/2003
Status Archive
Type General Article