Answers Database

Quicksim II: Could not find a registered simulation model, NULL model will be inserted


Record #1262

Product Family:  Software

Product Line:  Mentor

Problem Title:
Quicksim II: Could not find a registered simulation model, NULL model
will be inserted



Problem Description:
Quicksim may issue the following warning upon invocation:

//  Warning: Instance: '/GIVE_ME_AN_E'
//	  Could not find a registered simulation model with label: 'xc4000'
//	  NULL model will be inserted. (from: Analysis/Digital Simulation
Utilities/Dsim 85)

In some cases, the label for which Quicksim is searching may not be related
to a device family:

//  Warning: Instance: '/UNABEL'
//	  Could not find a registered simulation model with label:
'default/lca_technology'
//	  NULL model will be inserted. (from: Analysis/Digital Simulation
Utilities/Dsim 85)


Solution 1:

A bug in Fncsim8 and Timsim8 version 5.2.1 may cause these programs to
write out an incorrect simulation viewpoint when a design targets an
XC4000L device.  If you look at your fncsim8.log or timsim8.log file, you
will see a line that reads:

   pld_dve_sim design xc4000

Fncsim8 or Timsim8 is trying to write a simulation viewpoint for an XC4000,
but the design is expecting it to be written for an XC4000E, since the "E"
and "L" parts are functional equivalents.  Fncsim8 and Timsim8 only specify
the xc4000e argument if the device suffix is "E"; they do not do the same
if the suffix is "L".

A patch is available on the Xilinx FTP site that fixes Fncsim8 and Timsim8
by allowing them to recognize XC4000L parts as devices which use the
XC4000E library components.  (It also fixes Men2XNF8, which suffers from
similar problems.)  The patch can be downloaded from:

   ftp://ftp.xilinx.com/pub/swhelp/mentor/men_4kl.tar.Z

A README file is included.  Once the patch is installed, delete the
"default" simulation viewpoint underneath the top-level component
directory, then rerun Fncsim8 or Timsim8.  See Solution 766, "How to delete
a design viewpoint in Mentor 8," for more information.



Solution 2:

This can be caused by an incorrectly written simulation viewpoint for the
design, which usually comes about after a design is retargeted for a new
device family.	The solution is to run PLD_DVE_Sim on the design,
specifying the correct part family, from either PLD Design Manager or the
command line.  An XC4000 design, for example, would use:

   pld_dve_sim blanking_design xc4000

If a default viewpoint already exists, you will need to FIRST delete that
viewpoint before you can run PLD_DVE_Sim.  See Solution 766, "How to delete
a design viewpoint in Mentor 8."

Note: If Timsim8 -o was used to create the simulation model, be sure to run
Timsim8 instead of PLD_DVE_Sim.  This is because Timsim8 -o links timing
information into the viewpoint after it runs PLD_DVE_Sim.



Solution 3:

This error may be given on an ABEL module, or any other "black-box" module
that represents an XNF file.

When a design contains an ABEL module or other module that represents an
XNF file, Fncsim8 must generate a schematic for this block using the
GEN_SCH8 utility.  The component that represents this simulation schematic
is placed in the same directory as the ABL or XNF file referenced by the
FILE property on the symbol.  If a full directory path is not included,
then the ABL or XNF file is assumed to be in the MGD working directory,
referenced by $MGC_WD.	If the ABEL or XNF-referencing component is in a
different location from the corresponding ABL or XNF file, then the
resulting schematic will not be linked (registered) to the symbol,
resulting in the NULL-model message.

To avoid this problem, make sure that an ABL or XNF file referenced by a
design component resides in the same directory as the component.



Solution 4:

Another situation with a non-family model label may occur:

//  Warning: Instance: '/TYPECAST'
//	  Could not find a registered simulation model with label:
'lca_technology'
//	  NULL model will be inserted. (from: Analysis/Digital Simulation
Utilities/Dsim 85)

This may be caused by having the MODEL=lca_technology property on one or
more Xilinx primitives set to type "string" instead of type "expression".
The "lca_technology" in the MODEL setting is supposed to be replaced by the
family technology (e.g., xc4000e); this is what happens when the property
is of type "expression".  However, if the property is of type "string",
Quicksim interprets the "lca_technology" literally, instead of using the
correct family name in its place as it should.

To fix this, go to Design Architect and select a component about which
Quicksim is complaining.  (It should be a Xilinx Primitive.)  Then, select
Report -> Object from the menu bar.  The report Design Architect gives you
will tell you what type of MODEL property the component has.  (The MODEL
property should have a value "lca_technology".)  If the MODEL property is
of type "string", then proceed with the following steps.

1. Select Right Mouse Button (RMB) -> Select All -> By Property

2. In the Select By Property dialog box, enter the following information:

   Name: MODEL	 Value: lca_technology

   Then click OK.  This should select all components with a MODEL property
   set to "lca_technology".

3. Select RMB -> Update -> Symbol.  This brings in the Xilinx component with
   the (hopefully) correct MODEL property type.

4. Select Report -> Object from the menu bar.

At this point, the component's MODEL property should be of type
"expression".  If this is the case, check and save the sheet.  Then try
running Quicksim again.

If the component still has type "string", try this:

1. Select RMB -> Select All -> By Property

2. In the Select By Property dialog box, enter the following information:

   Name: MODEL	 Value: lca_technology

   Then click OK.  This should select all components with a MODEL property
   set to "lca_technology".

3. Select RMB -> Properties -> Modify

   Select the MODEL property in the dialog box, then make sure its
   parameters are set to:

   Value: lca_technology   Type: expression

4. Try Report -> Object again.

You should see your MODEL property set to type "expression".  Check and
save your sheet, then run Quicksim again.



End of Record #1262