Solutions Database

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ViewSim: Global reset signal names for 2k, 3k, 4k, 5k, 7k, and 9k (startup)

Record #128

Product Family:  Software

Product Line:  ViewLogic

Problem Title:
ViewSim:  Global reset signal names for 2k, 3k, 4k, 5k, 7k, and 9k
(startup)



Problem Description:
The first step when simulating a design in PROsim or ViewSim is to initialize
all the flip-flops.  To do this, the global signal must be asserted, time
simulated, and the global signal de-asserted.  The global signal is attached to
all the flip-flop simulation models and therefore must be used during both
functional and timing simlations.


Solution 1:

The following is a table of global signals and their polarities:

     Family   Signal   Operation   Active
     ------------------------------------
     XC2000    GR	Reset	    Low
     XC3000    GR	Reset	    Low
     XC4000    GSR     Set/Reset    High
     XC5200    GR	Reset	    High
     XC7000    PRLD    Set/Reset    High
     XC9500    PRLD    Set/Reset    High

NOTE:  The operation is based on the type of flip-flop that has been used.
For XC2000, XC3000, and XC5200 designs, only reset flip-flops can be used.
For XC4000, XC7000, and XC9500 designs, either set or reset flip-flops can
be used.

The following demonstrates how to assert a global signal for an XC3000 device:

Viewsim>> l GR
Viewsim>> sim 100ns
Viewsim>> h GR

If you do not assert the appropriate global signal, all the flip-flops in the
design will not function properly.  All the outputs will have the value `X'
which is the `UNKNOWN' value.  It is also recommended that all of your
external signals are assigned before the reset is asserted.

This solution applies to all Viewlogic simulation tools.  It also does not
matter if you have the "STARTUP" block included in the design.



Solution 2:





End of Record #128