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AR# 18179

6.1i SimPrim, Simulation - Post fit simulation shows data reaction on rising edge instead of falling edge

Description

Keywords: ISE6.1, ModelSim, library, timing, simulation, rising, falling, edge, XC9500XL

Urgency: Standard

General Description:
Post fit simulation of a XC9500XL design shows data reaction on rising edge instead of falling edge. Behavioral simulation shows the right result as well as post fit simulation with previous libraries (ISE5.2).

Solution

This problem is caused by a double inversion on the global clocks. The double inversion occurs when inverted global clocks are created by the user or the software.

To work around this problem, uncheck "Use Global Clocks" from Project Navigator.

This will cause a pterm clock to be used, and the double inversion will not occur.

This problem has been fixed in 6.1i Service Pack 3.
AR# 18179
Date Created 09/03/2007
Last Updated 11/18/2008
Status Archive
Type General Article