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AR# 10815

WebPACK - XPLA3 Latch fails in timing simulation.

Description

Urgency: Hot 

 

General Description: 

A simple latch functionally simulates properly, but fails in timing simulation.

Solution

This is fixed in the latest version of the WebPACK XPLA Fitter Module, which is 

available for download at: http://www.xilinx.com/products/software/webpowered.htm
 

The work-around for older versions of software is to open the time_sim.vhd file and look  

for the process statement that contains the latch; add the data input into the sensitivity list. 

 

Example:  

 

process(LH, AP, AR, D

begin 

if AR = '1' then 

Q_local <= '0' after tar2q; 

elsif LH = '1' then 

Q_local <= D after tLDI; 

elsif AP = '1' then 

Q_local <= '1' after tap2q; 

end if; 

end process;

AR# 10815
Date Created 08/29/2007
Last Updated 05/07/2014
Status Archive
Type General Article