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AR# 13374

4.1i NGDANNO - NGDAnno generates numerous warnings regarding zeroed negative setup times (Virtex-II designs)


Keywords: NGDAnno, zero, setup, time, warning, Virtex-II, negative

Urgency: Standard

General Description:
On certain Virtex-II designs, NGDAnno reports a number of warnings regarding zeroed negative setup times.


Negative setup times are not currently supported by NGDAnno. This will be supported in the next major Xilinx software release, which is currently scheduled for Summer 2002.

These warnings do not cause errors in simulation; however, they make the simulation more conservative. For example, if the original time was a 100ps setup on data with respect to a clock, NGDAnno will zero out this setup time. Therefore, the data must be valid at a 0 setup time (at the same time as the clock edge) instead of being valid up to 100ps after the clock edge.
AR# 13374
Date 08/15/2003
Status Archive
Type ??????