Preface

The Virtuoso^® UltraSim Simulator User Guide is intended for integrated circuit designers who want to use the Virtuoso UltraSim^™ Fast SPICE simulator to analyze the function, timing, power, noise, and reliability of their circuit designs.

This manual describes the following topics:

Licensing in Virtuoso UltraSim Simulator

Virtuoso UltraSim Licenses

Starting with the MMSIM 11.1 release, Cadence offers a base product plus MMSIM option licensing model. The Virtuoso^® UltraSim^® Circuit simulator is the base product, which offers the features shown in Table A-1 :

 

Table A-1  Virtuoso UltraSim^® Simulator

Features

Analog and Mixed Signal verification

Solver option/modes: A, S, MX, MS, DA, DF, and DX

Parasitic stitching

Parasitic reduction

Voltage regulator options

Static and dynamic device checks

Reliability analysis

AHDL Linter

The Spectre MMSIM options offered with the base product are shown in Table A-2. Both base product and options are accessible by using an a la carte license or Spectre MMSIM tokens.

 

Table A-2  Spectre MMSIM Options to Virtuoso UltraSim

Product Option	Description
Spectre Power option	An option used to run EMIR analysis with Virtuoso UltraSim simulator.
Spectre CPU Accelerator option	An option used to enable multi-core simulation up to 16 cores with Virtuoso UltraSim simulator base product. A quantity of 1 Spectre CPU accelerator option enables multi-core simulation for up to 4 cores and a quantity of 2 enables multi-core simulation for up to 16 cores.

Note: For additional details on licensing, pricing, and packaging contact your account manager.

The following documents give more information about Cadence token licenses and the FLEXlm^™ license manager.

License Checkout Order

The default license checkout priority for the Virtuoso UltraSim simulator is an a la carte license first and then Spectre MMSIM tokens. You can change the order of priority by using the +lorder command-line option. To make it easier to specify license names with the +lorder option, mnemonic license names are provided. Table A-3 shows the mnemonic license names and the corresponding license features.

 

Table A-3  Mnemonic License Names and Corresponding License Feature

Mnemonic Name	License Feature
MMSIM	Virtuoso_Multi_mode_Simulation
ULTRASIM	ULTRASIM_L

Using the mnemonic names mentioned above, the default license checkout order for features in the Virtuoso UltraSim simulator base product is:

ULTRASIM:MMSIM

Mixing of a la carte license and Spectre MMSIM tokens is not allowed. Therefore, the checkout order for the Spectre MMSIM options follows the checkout order of the base product.

Following is an example of specifying a customized checkout order, where an attempt is made to checkout the Spectre MMSIM tokens before the a la carte license:

+lorder MMSIM:ULTRASIM

Suspending and Resuming Licenses

You can direct UltraSim to release license(s) when suspending a simulation job. This feature is beneficial when you are using simulation farms wherein the licenses in use by a group of lower priority jobs might be needed for a group of higher priority jobs.

To enable this feature, start UltraSim with the +lsuspend command-line option. You can then suspend the simulation and release all the licenses in use by pressing Ctrl Z on your keyboard. If you want to resume a suspended simulation, enter fg.

Note: Pressing Ctrl Z will release the license only if you have used the +lsuspend command-line option. If not, pressing Ctrl Z will stop the simulation but the license will not be released. In addition, these keystrokes might not work if you have changed the default key bindings.

Tracking Token Licenses

You can use the UltraSim log file or the lmstat UNIX shell command to track token license activity.

UltraSim Log File

The UltraSim log file shows the license checkout status. For example:

Connecting to License Server ... Done.

Successful checkout of ULTRASIM_L license with total wait time of 0 sec.

lmstat Utility

The lmstat utility can be used to track token license activity. This utility reads the license.file and displays specific information when using the following options.

 

Option	Description
-a	Display all of the information
-c license_file	Use "license_file" as license file
-f [feature_name]	List usage information about specified (or all) features
-i [feature_name]	List information about specified (or all) features from the increment line in the license file
-S [DAEMON]	Display all users of DAEMONs licenses
-s [server_name]	Display status of all license files on server node(s)
-t timeout_value	Set connection timeout to "timeout_value"
-v	Display FLEXlm version, revision, and patch

For more information on lmstat, refer to the Cadence License Manager manual.

Related Documents for Virtuoso UltraSim Simulator

For additional information about the Virtuoso UltraSim simulator and related products, refer to the following manuals:

Typographic and Syntax Conventions

The following typographic and syntax conventions are used in this manual.

Commands

command_name [argument(s)]

argument types: keyword | value | tag = keyword | tag = value

 

Table A-4  Virtuoso UltraSim Argument Types

Argument Type	Definition
keyword	Keywords are the identifiers in a card that are defined by the Virtuoso UltraSim simulator.
value	Values are user-defined. These include elements names, node names, expected values, and value arguments to tags. They are shown in italics to emphasize that they are user-defined, as opposed to keywords and tags that are defined by the Virtuoso UltraSim simulator.
tag	Tags are identifiers in a card to which a value or keyword can be assigned. An example are the tags for element instance parameters (for example, MOSFET W, L, AS, AD). Tags can have values or keywords as arguments, as specified by the command syntax.

 

Table A-5  Virtuoso UltraSim Symbol Types 

Symbol Type	Definition
bar |	Represents the word OR, so you can choose between arguments.
ellipsis ...	Allows you to specify multiple arguments.
brackets [ ]	Indicates the enclosed argument is optional.
parentheses ( )	Indicates there is a choice between the enclosed arguments (two or more), and is only used when a command uses several groups of arguments.

In the following example, the statement specifies a Cxx capacitor, and n1 and n2 nodes. The c and m keywords have values assigned to them to specify the capacitance and multiplier factors, respectively (keywords are optional and are defined by square brackets). The values are displayed in italics to emphasize that the values are user-defined.

Cxx n1 n2 [c=value] [m=value]

In this Spectre format example, the usim_opt speed command expects a 1 or 2 as a value argument.

usim_opt speed=1|2

Note: A period (.) is required when using SPICE language syntax (for example, .usim_opt speed).

Syntax

Note: Do not leave a space between the number and suffix (for example, 10m, 1e-5sec).