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Performing Circuit and Device Checks

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ADE Assembler provides an interactive user interface where you can define circuit or device checks that are performed using the simulation results. The violations of these checks are highlighted on the Checks/Asserts view on the Results tab. You can view and analyze the violations by using the various features of this view, such as, filtering violations using the built-in or custom filters, finding the critical instances or nets on the schematic, or highlighting the violation results on the waveforms. Next, waive or resolve the violations as per your requirements, and rerun simulations to verify the results.

This chapter describes how to use the tools and features in ADE Assembler to perform circuit and device checks, and to resolve violations:

• An Introduction to Checks and Asserts
• Adding Checks and Asserts
• Filtering Violations
• Running Simulations and Viewing Violations

An Introduction to Checks and Asserts

This section provides an introduction to the types of checks supported by ADE Assembler. It also introduces the Checks/Asserts tree in the Data View assistant pane.

Checks

Checks (or circuit checks) enable you to analyze typical design problems, such as high impedance nodes, leakage paths between power supplies, setup and hold timing errors, power issues, connectivity problems, or extreme rise and fall times.

Circuit checks are of two types shown below.

For more details on the circuit checks that can be performed by the Spectre simulator, refer to Circuit Checks in Spectre Circuit Simulator and Accelerated Parallel Simulator User Guide.

Asserts

Asserts (or device checks) are used to perform checks on design parameters, node voltages, element currents, model parameters, operating point parameters, and expressions. In Spectre, the assert and checklimit statements are used to define and run device checks.

For details and examples on the device checks that can be performed by the Spectre simulator, refer to Device Checks in Spectre Circuit Simulator and Accelerated Parallel Simulator User Guide.

Dependency on Simulators

In ADE Assembler, you can perform all the circuit and device checks that are supported by the MMSIM 14.1 ISR11 or later releases. The checks should be defined using the required syntax and keywords, and can include wildcard characters, subcircuits, and instance scoping. Spectre writes the results of these checks into the SQLite database in XML format. ADE Assembler reads that data and displays it in tabular format on the Results tab.

Setting up Checks and Asserts Analysis

To set up checks and asserts:

1. Select and expand Checks/Asserts in the Data View assistant of ADE Assembler.
   All tests defined in the current maestro cellview are displayed under this node. By default, the check boxes for all tests are deselected. Tests that are disabled in the Tests node are disabled in this tree as well.
   
   If the enableDochecklimitFromDataView environment variable is set to t, the tool automatically updates the dochecklimit check box on the Checks tab of the Simulator Options form for the enabled tests under the Checks/Asserts node in the Data View assistant.
2. In the Checks/Asserts node, select the check boxes next to the tests for which you want to enable all the defined checks.
3. Expand the tree for a selected test.
4. Expand the Cellviews node under that test node to view the names of the schematic cellviews in that tests.
   For each schematic cellview, the tool displays the total count of checks and asserts defined in that schematic.
   
   
5. If the number of cellviews in your design is large, use the commands in the context menu of the Cellviews node to show or hide only those cellviews that contain checks:
   • Show Cellviews without Checks
   • Hide Cellviews without Checks
     
     
6. Select or clear the check boxes next to the schematic name for which you want to include the checks in the analysis.

You can define checks for cellviews in the Checks/Asserts assistant. For more details, see Adding Checks and Asserts.

Adding Checks and Asserts

Checks can be added in the following two ways:

• By using the Checks/Asserts assistant in the Virtuoso Schematic Editor window
• By copying the Checks/Asserts from One Cellview to Another
• By importing asserts from included text files
• By defining global device checks using the Device Check Options form

While you are adding checks and asserts in the Checks/Asserts assistant, you can also verify how they will be added to the netlist to be used in simulations. For details, see Viewing Netlists for Checks and Asserts.

Adding Checks using the Checks/Asserts Assistant

To add checks for a test, perform the following steps:

1. In the Data View pane, expand the Checks/Asserts tree.
   The names of all the tests defined in the current view are listed in this tree.
2. Expand the test tree for which you want to define checks.
3. Click Click to edit checks.

The schematic view of that cell is opened in a new tab.

By default, the Checks-Edit workspace is opened. This workspace shows the Checks/Asserts assistant pane on the left.

To add new checks for this test, perform the following steps:

1. In the Checks/Asserts assistant, click the checks drop-down list, and choose the type of check you need to create. For example, Circuit Checks – Dynamic.
   
   If the drop-down list is disabled, ensure that the constraints view is editable. If not, use the Make Editable command in the Checks/Asserts assistant, as shown below.
   
   The list of dynamic checks for which templates are available in Spectre are shown in the submenu.
   
   
   The check is added to the list of constraints in the Checks/Asserts assistant. Its corresponding parameters are displayed in the constraint parameters pane.
   There is no list of checks for Device Check. For this type of checks, you can directly provide parameters in the Editor pane.
   
   Any custom or default system constraint created in the Constraint Manager assistant can be propagated automatically to the Checks/Asserts assistant. For information about how to enable the automatic propagation, see Propagating Constraints to the Checks/Asserts Assistant in Virtuoso Unified Custom Constraints Configuration Guide.
2. Move the pointer over a check name in the top area of the assistant to view its definition and parameters in a tooltip.
   
   If the Editor pane is not visible, click Checks/Asserts Editor ( ) on the assistant toolbar.
   
3. Edit the check parameters as required. You can define the scope for a check by setting the Node, Device, and Inst fields.
   Either type the names of nodes, devices, and instances, or directly select these from the schematic.
   
   
   To apply a check for all the nodes or instances, enter * in the respective field.
   If a field value for a parameter is unchanged, it will use the default values for that parameter as defined in the simulator file. The default values can be found in two ways:
   • By using the spectre -help <checkName> command, as shown below.
     

     spectre -help assert

     spectre -help dyn_highz

   • By moving the pointer over any check parameter in the Editor pane. The definition and default value for a parameter is displayed in the tooltip.
4. Repeat steps 1 to 3 to add more checks.
5. Click Save in the toolbar to save the checks.
   
   It is required to save the checks to ensure they are netlisted correctly. If you run simulation without saving changes in the constraints view, ADE Assembler displays a message and prompts you to save changes.
   The Checks/Asserts — <testName> — Cellviews tree lists all the cellviews contained in the design under test. The numerical value next to each cellview shows the count of checks defined for each. To edit the checks for a cellview, right-click it and choose Edit Checks. The cellview is opened in the schematic view where you can add or edit checks in the Checks/Asserts assistant.
   
   An example displaying a circuit check and a device check is shown below.
   
   
   The checks and asserts defined for a cell using the Checks/Asserts assistant are stored in a special partition of the constraint view for the cell. These checks will be netlisted using the subcircuit parameter to keep the scope of the check to the cellview in which it is created. These checks are included in the simulation whenever that cell is instantiated in a design.

Copying Checks or Asserts

If the check or assert you need to create for a cellview already exists for another cellview instantiated in the design, you can copy that and customize it, if required.

To copy a check or assert, perform the following steps:

1. Right-click the source cellview from which you need to copy the check or assert, and choose Edit Checks.
   
   
   The constraint view of the cellview is opened in a new tab and the checks/Asserts assistant is displayed.
2. Right-click one or more checks and asserts to be copied and choose Copy Checks/Asserts from the context-sensitive menu.
   
   
   The copied check or assert is saved in the memory.
3. Reopen the maestro cellview tab.
4. Right-click the cellview to which you need to copy or reuse the copied check or assert, and choose Edit Checks.
5. The constraint view of the target cellview is also opened in a new tab and the Checks/Asserts assistant is displayed
6. Ensure that the constraint view is editable. If not, click Save Checks/Asserts – Make Editable.
7. Right-click anywhere in the checks/asserts pane and choose Paste Checks/Asserts.
   The copied check or assert is added to the cellview. You can view and edit its parameters in the parameter editor pane of the Checks/Asserts assistant.
   
   

Importing Asserts from Text Files Included in the Setup

If you have defined device checks or Spectre asserts in model files, you can include those files for a test.

To import device checks, perform the following steps:

1. In the Data View pane, expand the Tests tree.
2. Right-click a test and choose Model Libraries.
   The Model Library Setup form is displayed.
3. Click <Click here to add model file> to view the Browse button.
4. Click Browse and select a model file that contains the definitions of device checks.
   
   
5. (Optional) If you want to view or edit the asserts, select the name of the model file and click Edit/View Selected Files.
   
   
6. Click OK to apply the changes and close the form.

The asserts included from the model file will now be included in the netlist and used in simulation runs.

Defining Global Device Checks

Using the Device Checking Options form, you can specify the global device check options, such as start and stop times for a transient analysis and default severity for various Spectre analyses.

To open the Device Checking Options form:

1. Right-click a test and choose Options – Analog from the context menu.
   The Simulator Options form appears. For more information about how to use this form, see Setting Spectre Options.
2. Open the Check tab.
3. Select the yes check box for dochecklimit to enable device checks.
4. Click the Options button available at the bottom of the Check tab.
   The Device Checking Options form appears, as shown in the figure below.
   
   

When you open this form, the Transient tab is open by default. You can also use this form to specify the global device check options for various analyses.

The following fields are displayed on the Transient tab:

• Start Time for Device Checks–Specify the beginning time at which device checks are to be enabled or disabled for transient analyses.
• Stop Time for Device Checks–Specify the end time at which device checks are to be enabled or disabled for transient analyses.
• Severity–Select the default severity level for the message that is displayed when Spectre reports violations for the device checks that are enabled for transient analyses. The available options are: None, Error, Warning, Notice, and Fatal.
  The specified severity level overrides the severity level specified for individual checks in the Checks and Asserts assistant.
  
  If you set the severity to None, the severity level specified for individual checks in the Checks and Asserts assistant will be used.
• Check Windows–Specify the time windows when device checks will be enabled. In the Begin and End columns, specify the begin and end times for each time window, one per line in the table.
• Enable All Checks–Select this check box to enable all the device checks for transient analyses.
  
  If this check box is not selected, only the device checks that are enabled for transient analyses in the Checks and Asserts assistant are used for transient analyses.
• Disable All Checks–Select this check box to disable all the device checks for transient analyses.

The remaining tabs, DcOp, Dc, Ac, Sp, Noise, and Pz, include only three fields as shown in the figure below:

Viewing Netlists for Checks and Asserts

While you are creating or editing checks and asserts in the Checks/Asserts assistant, you can also view how they will be added to the netlist for simulation. You can do this in two ways:

• Viewing netlist statements for all the checks/asserts in a text window
• Viewing the netlist preview for an individual check in the tooltip

Viewing netlist statements for all the checks/asserts in a text window

You can generate the netlist for all the checks and asserts defined at the current design hierarchy level by using the Netlist Checks/Asserts command in the Device Check drop-down menu on the Checks/Asserts assistant toolbar. This command opens a netlist window that shows all the checks defined at the current level.

For each design level, you need to run this command separately to view the netlist at that level.

Viewing the netlist preview for an individual check in the tooltip

To preview the netlist for a single check, move the mouse over the check name in the Checks/Asserts assistant. A tooltip will be displayed where you can view the netlist statement.

If the netlist for a particular check at the subcircuit level is not valid, appropriate warnings are displayed, as shown below.

Next Steps

After creating circuit checks, the next steps are to:

• Define violation filters and specifications on the Outputs Setup tab
• Run simulations
• View violations on the Results tab

Filtering Violations

Violation filters provide a way to visualize the different metrics for checks, such as the number, duration, or any user-specified categories of violations. Each violations filter can have its own specification and is treated like any other output.

To create a violation filter, perform the following steps:

1. On the Outputs Setup tab, click Add new output — <testName>— Violation Filter to add a new output to show violation filters for checks or asserts.
   
   
   A new row is created with its type set as violations.
2. Enter a name in the Name column for the violation output.
3. Double-click the Details column for this row.
   
   
   The following three drop-down lists are displayed:
   • The first drop-down list is the type of operation you want to perform. For example, you can select Count to count the number of violations. Other operations available in this drop-down list are Avg, Min, Max, or Sum.
   • The second drop-down list specifies the field you want to access within the violation result. For example, for the Avg such as Duration or PeakValue. If the first value is Count, the second value defaults to *. Otherwise, the choices in the second list vary depending on the item select in the third list.
   • The third drop-down list shows the list of checks defined for the test. Choose a check on which you want to run the operation selected in the first drop-down list. You can select an individual violation type, for example, Dynamic HighZ Node Check or a grouped category, such as Dynamic Checks or All Checks/Asserts. The second list of fields is updated depending on the selection in this list.
     
     
4. Select values from the drop-down lists to build an expression for the violation filter.
   Example expressions:
   • Count 'Device Checks'
   • Max 'RMS(W)' on 'Dynamic Subckt Port Power Check - Port Power Report'
5. Add a specification for the violation in the Spec column for the output.

Running Simulations and Viewing Violations

After adding checks in the Checks/Asserts assistant and defining violation filters in the Outputs Setup pane, you can run a simulation to run the checks on the simulation results. After the simulations of all points and corners are complete, the Detail results view shows a consolidated report of the violation filter expressions defined in the Outputs Setup tab. For example, Count reports the number of violations of the specified type.

If no violations are found, the result for the violation filter shows No violations. When violations are reported, the status is either pass or fail.

The following table lists the possible result values for the violations type of outputs:

Result Value	Description
<count of violations>	Indicates that the simulation was run and found a number of violations for this output.
No violations	Indicates that the dochecklimit device checking option on the Checks tab of the Simulator Options form is disabled or The check or is disabled in the constraint view
undefined	The given type of check is not defined or is disabled in the maestro cellview. For example, if the static type of checks are not defined in the maestro cellview, as shown below. In this case, the count 'Static Checks' output shows the result value as undefined.
Canceled	If a simulation is canceled before completion, ADE Assembler looks for violations in the results database. If found, violations are displayed on the Results tab. Otherwise, it displays Canceled. In this case, you can click the drop-down button next to the command on the Results tab and select Partial Data to re-evaluate results using the partially complete simulation data. If partial data is available, Assembler loads the violations from that data. It also displays a warning icon next to the values to indicate that they are based on partial data.
disabled	Indicates that no checks or asserts was run, and no SQL database was generated. This could be because: The Checks/Asserts check box in the Data View assistant is disabled or an error was found in the checker definition

The violation count value for each corner is a hyperlink. Click any value with hyperlinks to display the detailed results that contributed to this value. The net- or instance-wise details are opened in Checks/Asserts results view. With an aim to resolve violations, you can use the hyperlinks in that detailed view, find the violating nodes or instances, waive violations, or add comments.

The Checks/Asserts results view provides a lot of controls to customize the display of violation details, as shown below.

To check or edit the details of any device check directly from this view, click on the corresponding instance name in the Inst/Net column of the results table. The schematic of the instance is opened in a new design tab within the ADE Assembler window. The Checks-Debug workspace of the schematic view shows the Checks/Asserts assistant where you can view or edit the details of a device check.

Related Topics

refreshViolationPerCorner

Exporting Checks/Asserts Results

You can export the results displayed in the Checks/Asserts results view into a CSV file. For this, click Export Outputs to CSV File on the toolbar. The Export Results form is displayed. Specify a file name and choose a file type as .csv or .html. Click OK to export the results.

For Checks/Asserts results, the tool exports the data in batch mode with the default set of 10000 rows in a batch. You can change the batch size by setting the exportBatch environment variable. While exporting data, the tool shows a progress bar at the bottom of the Results tab. After the data is successfully exported, a message is displayed to report the number of rows exported to the CSV file.

Related Topic

exportBatch

The following sections provide details about how to customize the violations display:

• View itemized violations details
• Waive violations
• View cumulative violation details
• View summary of violations
• View instances with violations on schematic
• Create a custom violation filter
• View violation in ViVA XL graphs
• View violation reports in Web browser
• Viewing results of device checks

Viewing Itemized Violation Details

In the itemized view, the details of each violating net or instance for a given test/design point/corner combination are displayed in the Checks/Asserts results view. The names of the test for which the results are displayed appears at the top. You can select a different test from the Test drop-down list.

Customizing the Display of Violations in the Checks/Asserts Table

You can customize the view of the Checks/Asserts table in the following ways:

• Hide the columns you do not want to see. For this, use the Hide Column command from the context-sensitive menu of the Checks/Asserts table.
  You can use the Show All Columns command to show the hidden columns.
• Change the order in which columns are displayed. For this, select the column you want to move, drag it to the location where you want to place it.
• Apply a field or column filters to view the selected violation data. Columns such as Point, Corner, or Analysis Name have drop-down filters that you can use to select a specific value to filter data.
  Columns such as Checker Name, Inst/Net, Time (s), Duration (s), and Comments provide enhanced filters where you can type in the filter criteria using specific values and wildcard characters. Specify a criterion and press Enter to view the filtered rows.
  
  To use a particular value from a column as the filter criterion for that column, right-click the value and choose Send to Column Filter. The selected value appears in the Filter cell of the column, and only the rows containing that value are shown in the outputs table.
  
  Note the following important points about the column filters:
  • You can apply filters in multiple columns together.
    The following example shows how column filters have been used to view all the violations for corner C0_2 where Checker Name contains step and Time (s) is between 85p and 5n.
    If you are not using comparison operators, the numerical values are compared like strings.
    
    
  • You can use numerical comparison operators, such as > or <, as shown for the Time (s) column in the above example.
  • You can use filtering options from the context-sensitive menu of the cell in which you applied a filter. These options are same as the filtering options in other result views.
    
    
    In the Message, User Message, Comment, and Expression fields, you can use the Any of the words filtering option to filter the rows that contain any of the multiple strings specified in the Filter cell.
  • You can choose filters from the drop-down list. As shown in the example given below, the list shows available values including the previously used filters and the unique values in that column.
    
    
  • You can clear the previously used filters for a column by using the Clear Search History command in the context-sensitive menu of that column.
    
    
  • You can save the current set of filters in the Checks/Asserts table with a name. For this, specify filters in all the required columns, type a name in the drop-down list for violation filter selection. Right-click the drop-down list and choose Save.
    
    
    The filters are saved in the .cadence/dfII/maestro/check-filters directory and are available for use when you reopen the cellview later.
    Later, you can reapply a saved filter by selecting it from the list of violation filters. If not required, you can delete a saved filter by using the Delete command in the context-sensitive menu of the drop-down list.
    The saved filters are also available in the Customize Violation Filters form, where you can modify them further.
  • You can hide the filters by using the Hide Filters command from the context-sensitive menu of the column headers in the Checks/Asserts table.
    
    If required, you can choose to waive a few violations by using the Waive Violation(s) command in the context-sensitive menu of the violation rows. While you mark a violation as waived, you can also add a comment providing the reason or other information about that. These comments are visible in the the Comment column (the right-most column in the Checks/Asserts table).

Waiving Violations

When you waive a violation, all the relevant violations that occur under the same check/assert, on the same design object and in the same analysis are waived. If there are certain violations that can be ignored, you can choose to wave those off. For example, you can choose to waive all the violations that have the start time before 5n.

To waive a violation, perform the following steps:

1. Click the header of the StartTime (s) field to sort the values in ascending order.
2. Hold the Shift key and select all the rows that have values less than 5n. Right-click anywhere in the selected rows and choose Waive Violation(s). The Waive Violation(s) form is displayed.
   
   
3. Add an appropriate comment in the Comment field.
4. You can choose to waive:
   1. The violations under the selected time points by selecting the selected time point(s) option.
   2. The violations across all time points by selecting the all time point(s) option.
   
   For this example, ensure that the selected time point(s) option is selected.
   Additionally, you can use the environment variable waiveViolationsByCorner to waive only the violations under the same design point and corner.
5. Click OK.

For the waived violations, the Status field shows the status as Waived. and the Comment field shows the comments you added on the Waive Violation(s) form.

You can later review and clear these waivers by using the Clear Waiver(s) command in the context-sensitive menu of the violation rows.

Importing Waiver Status

To import the waiver status for violations from some other combination of test, design point, and corner, perform the following steps:

1. Click Apply waiver status from another test and/or history on the toolbar.
   The Import Waiver Status form is displayed.
   
   
2. From the History and Test lists, select the names of the history and test from which you need to import waivers.
3. (Optional) Change the criteria for the start time value defined in the Apply waiver when violation start time within field.
   This field controls whether a waiver will be applied or not by comparing the violation start time in the current results and the violation start time in the imported waiver. If the difference in the two values is less than the value specified in this field, the waiver is applied, otherwise it is skipped. This is useful where a violation occurs across multiple corners/points or runs, but the start time varies slightly due to differing circuit conditions.
4. Click OK.
   ADE Assembler identifies the violations for which waivers can be applied and shows a summary in the Import Waiver Status Summary window, as shown below.
   
   
5. Click OK to import the violations.
   The waivers are imported and applied to the same violations in the current test, corner, and design point combination. The Status and Comment fields are also updated.

View Cumulative Violation Details

Selecting the Cumulative check box shows the cumulative results across time where a row is shown for each unique check. The Count column for each check shows the number of times for which a violation occurred for a particular net or instance.

If you click the hyperlinks in the Count column, a table is displayed at the bottom of the Checks/Asserts view that lists all the time points when the violation occurs and other details of the check that differ at each time point.

View Summary Violation Details

Selecting the Summary check box shows the count for each check or assert violation across all instances for each combination of corner and analysis name.

View Instances with Violations on Schematic

If you want to view which nets or instances in the schematic view are violating a check, click an instance or a net name in the Instance column. The schematic view is opened in a new tab within the ADE Assembler environment, as shown below.

The violating net or instance is highlighted and zoomed into. The zoom scale is controlled by the autoZoomScale environment variable. You can disable the automatic zooming by setting the adexl.gui zoomToProbedInstOrNet environment variable to nil.

The schematic view shows the lower-level subcircuit that contains the selected net or instance.

Also see: adexl.gui descendIntoSubcktForShowingInstOrNet

Creating Custom Violation Filter

By default, the drop-down list to select a violation filter shows the three main types of checks, Device Checks, Dynamic Checks, and Static Checks; and the checks for which violations exist are listed under their appropriate types, as shown below.

If required, you can create your own custom violation filters with different criteria and save them so that they can be reused for the same or different results.

To define and save a custom filter, perform the following steps:

1. Click Edit or Create custom violation filter ( ) on the toolbar to open the Customize Violation Filters form.
   
   
2. Specify values in the following fields to create a custom filter:
   

   Form Field	Description
   Filter Name	The name of the filter
   Description	The description for the custom filter
   Shows	The type of checks to be displayed by this filter.
   Available Fields	The list of fields or columns available for the selected check type. This list varies for different types of checks.
   Cumulative	Specifies if the filter results should be cumulative.
   Where	Specifies the filter criteria. To define this criteria based on the values in a field or column, click the column name in the Available Field list and click the left arrow. The field name is added to the Where field. You can now build an expression to define the filter criteria.

   
   An example of a custom filter that checks the duration of a violation is shown below.
   
   
   Another example of a custom filter that filters the device checks where violations are more than 10% above the maximum limit is shown below.
   
   
3. Click Save on this form to save these filter settings in a custom filter.

Important Points to Consider for Custom Filter Syntax

• Instance and net names must use the simulator namespace, not the schematic namespace. For example, I8.I0.MP1is correct, whereas /I8/I0/MP1 is incorrect.
• Query operators are case insensitive
• Strings can be in single or double quotes
• If the field names contain spaces or special characters, they must be enclosed in double quotes.

Query Operators for Custom Filters

Custom filters support all SQLite operators. Some of the commonly used operators are listed in the table given below.

Operator	Definition	Example
=, ==, !=, <>	Equal, not equal	"Inst/Net" = 'I18.NM0'
IS, IS NOT, NOT	Equality operators. Use this to query the Status column	"Status" IS NOT "Waived"
>, <, >=, <=	Greater than, less than, greater than or equal, less than or equal	"Duration (s)" > 20n
BETWEEN	Between an inclusive range	"Time (s)" BETWEEN 10n AND 30n
IN	List of possible values	"Checker Name" IN ('vgs_nch', 'vgs_pch')
LIKE	Searches for a case insensitive pattern. % is used to define wildcards before and after the pattern.	"User Message" LIKE '%exceeds%'
GLOB, MATCHES	Case sensitive string matching that uses * and ? wildcards	"User Message" GLOB '*g45?1svt*VGS*' "User Message" MATCHES '*g45?1svt*VGS*'
CONTAINS	Shortcut for GLOB '*foo*'	"User Message" CONTAINS 'exceeds'
STARTSWITH, ENDSWITH	Shortcut for GLOB 'foo*', GLOB '*foo'	"Inst/Net" STARTSWITH 'I18' "Inst/Net" ENDSWITH 'NM0'
AND, OR	Combines multiple search expressions	"Status" IS NOT "Waived" AND "Time (s)"

Viewing Violations in ViVA XL

For violations that occur on nets, ADE Assembler lets you:

• Click the hyperlinks in the Time(s) column of the Checks/Asserts results view to plot the time and duration for which a particular result was violating.
• Click the hyperlinks in the StartTime(s) column of the results view for device checks to plot the values given in the Message column.
  To enable this feature:
  • Set the option wfdebug=assert in the Additional Arguments field, in the Miscellaneous tab of the Simulator Options form. This also ensures that the signals to be plotted are automatically saved in the outputs setup.
  • Ensure that you use Spectre 21.1 ISR15 or higher release versions.

The transient analysis result for that net is displayed in the Virtuoso Visualization & Analysis XL window. The start and end times for the violation are marked with vertical markers and the violation area is highlighted. You can also see how the given value varies with time. A bookmark also shows the check details, as shown the figure given below.

View Violations in Browser

In the Detail results view, right-click the result of a violation filter and choose any one of the following commands to view results in a browser:

• View Netlisted Checks/Asserts: Opens a browser to display the checks and asserts as they are netlisted. Checks for each cellview are displayed in a separate tab, as shown below.
  
  
• View Dynamic/Static Violation Report: Opens a browser to display the XML results for static and dynamic circuit checks in separate tabs, as shown below.
  
  

envSetVal("adexl.results" "checksAssertsViewTool" 'string "firefox")

Viewing Only Device Checks

Asserts or device checks are used to perform checks on design parameters, node voltages, element currents, model parameters, operating point parameters, and expressions.

To view the results of the performed device checks, select Device Checks from the drop-down menu.

The following fields appear:

Field Name	Description
Status	Waiver status for violations.
Point	Number of sweep points.
Corner	Name of the corner.
Checker Name	Name of the assert.
Analysis Name	Name of the analysis.
Instance	Name of the instance.
Model	Model or subcircuit name related to the device check.
Count	The number of times for which a violation occurred for a particular net or instance.
First Time(s)	Start time of the first violation.
Cumulative Duration (s)	Sum total of the time duration of the violations for a given net or instance.
Max Peak Value	Maximum peak value
Max Margin	Margin of the maximum peak value violation.
Max Violating Ratio	Violation ratio of the maximum peak value violation.
Max Peak Time	Start time of the maximum peak value violation.
Max Peak Duration (s)	Time duration of the maximum peak value violation.
Model	Model name of the device.
StartValue	Start value of the violation.
Margin	Difference between the violation start value and the minimum or maximum parameter values.
StartTime (s)	Start time of the violation.
Duration (s)	Duration of the violation.
Duration (%)	Duration percentage of the violation, which is calculated as follows: Here, Duration is the duration of the violation and the Transient Analysis Length is the stop time specified for the transient analysis.
EndTime (s)	End time of the violation.
EndValue	End value of the violation.
AvgValue	Average value of the violation.
Message	Message that Spectre writes to the log file for the start of the violation.
Max Message	Message that Spectre writes to the log file for the maximum peak value violation.
Max Dissatisfied	The part of a boolean assert expression that was not satisfied for the maximum peak value violation.
ViolationType	upper when maximum value is violated. lower when minimum value is violated.
PeakStep (s)	Time step at peak value.
PeakValue	Peak value. In an assert check of Boolean type, the peak value is not printed by default. Use extreme=yes in the assert statement to enable printing of peak value in this column.
Dissatisfied	The part of a boolean assert expression that was not satisfied.
ViolatingRatio	Percentage of violation detected above or below the specified minimum or maximum value in the checker definition. To view this field, set the following Spectre option: sqldb_violating_ratio=yes This field can also be viewed on selecting a dynamic mosv violation filter.
Min	Minimum value in the checker definition.
Max	Maximum value in the checker definition.
Expression	MDL expression that is checked.
Level	Severity level of the message if the check fails. It can be one of the following values: notice or warning: The simulation continues after the message is displayed. error: Spectre aborts the analysis when the first error-level violation occurs. fatal: Spectre aborts the simulation when the first fatal violation occurs. Default value: warning
User Message	Message extracted from the message= parameter. Any hypertext links given in this field are displayed as hyperlinks.
Comment	Comments added to the Waive Violation(s) form.

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