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AR# 110

Viewlogic Simulation - If a value is forced to a signal and then released, FLOATVAL attributes will be cancelled

Description

Keywords: Viewlogic, simulation, FLOATVAL, signal

Urgency: Standard

General Description:
When simulating a design, if a node that has a FLOATVAL attribute is forced and then released, the FLOATVAL value will not be restored. Once released, the node will go to high impedance.

Solution

For example:

The global set/reset signal for the XC4000 family of devices known as GSR has a FLOATVAL=0. Before GSR is asserted, and after simulation occurs for some amount of time, GSR takes on the FLOATVAL value of "0". Once GSR is asserted to "1", if it is released using the "r" command, it will take on the value of "Z". Because this value is unacceptable, GSR must be driven Low to de-assert it so that it takes on the value of "0".
AR# 110
Date Created 08/31/2007
Last Updated 02/24/2003
Status Archive
Type ??????