Product Documentation
Virtuoso Schematic Editor User Guide
Product Version IC23.1, November 2023

6

Automatically Creating Cellviews

This chapter discusses the following topics:

Features of Creating Cellviews

You can automatically

The software uses the TSG program to generate a symbol when you choose either Create – Cellview – From Cellview or Create – Cellview – From Pin List.

Automatically Creating a Cellview from Another Cellview

You can automatically create a new cellview from an existing cellview. For example, you can automatically create a symbol from a schematic. Automatic cellview creation can be useful for both top-down and bottom-up design approaches.

To create a cellview from another cellview,

  1. From the view, choose Create – Cellview – From Cellview.
    The Cellview From Cellview form appears.
    By default, the software initializes the form with information about the cellview currently open (the default cellview).
  2. Use a different cellview as the source of the port/pin information by changing the Library Name, Cell Name, and From View Name fields.
  3. Change the To View Name or Tool / Data Type field to change the cellview to be created.
    If either the From View Name cyclic field or the Tool / Data Type cyclic field does not contain the desired view or conversion function, you must modify the schViewToPinListReg list or the schPinListToViewReg list, which are defined in your schConfig.il file, which is described in Virtuoso Design Environment User Guide.
  4. Display the cellview in a new window by turning on the Display Cellview button.
  5. Edit various cellview creation options by turning on the Edit Options button.
  6. Click OK.
    When generating a symbol, the Symbol Generation Options form appears if you turned on the Edit Options button and the cellview is being newly created or replaced.
    If a cellview already exists with the same name, a dialog box prompts you to either replace the cellview, modify it (symbol cellview only), or cancel the command.
    From this point, the exact behavior of the command depends on the type of data being created.
If a symbol view has been created from a schematic view that contains nets that have a defined sigType property (by default “signal”) and pins, then each symbol pin will inherit a sigType property that has the same value of the corresponding net.

Replacing an Existing Symbol Cellview

You can replace or modify existing symbol cellviews. You can only replace (not modify) all other types of existing cellviews.

  1. From the schematic window, choose Create – Cellview – From Cellview.
    The Cellview From Cellview form appears.
  2. In the To View Name field, type symbol.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    Replacing the symbol cellview does the following:
    • Discards any modifications you may have made to that cellview
    • Creates only the pins, properties, selection box, labels, and other graphics; all schematic instances, schematic wires, and HDL body text are lost
    • May alter the position of pins in the new symbol cellview
  4. Click Replace.
    The Symbol Generation Options form appears.
  5. Click OK.
    The Overwrite Base Cell CDF dialog box appears.
    The existing cellview is deleted and a new one is created.
  6. Click Yes.

Modifying an Existing Symbol Cellview

You can replace or modify existing symbol cellviews. You can only replace (not modify) all other types of existing cellviews.

  1. From the view, do one of the following:
  2. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    Note: Before clicking Modify, be aware that modifying a symbol cellview will:
    • automatically edit the cellview with a minimal amount of changes to the current pin locations, graphics, and properties within the symbol cellview.
    • delete pins that are no longer needed.
    • add pins that do not yet exist in the new cellview.
    • add pins near the bottom of the cellview. Use the symbol editor to reposition these new pins and to adjust any symbol graphics. The system determines attributes of the new pins by the currently active TSG template file (see Loading and Saving a TSG Template File).
    • add or update cellview properties and terminal properties.
    • annotate the changes that were made in note format at the bottom of the cellview and in the Command Interpreter Window (CIW).
    • not delete cellview or terminal properties.
  3. Click Modify.
    The symbol cellview is automatically edited and saved.
    The Overwrite Base Cell CDF dialog box appears.
  4. Click Yes to update the base cell CDF with new simInfo port information (see Figure 6-3).

Examples of Replacing and Modifying Pins on a Symbol

The following three figures show the difference between choosing Replace and Modify.

Figure 6-1 illustrates an original symbol that was created using Create – Cellview – From Cellview from a schematic that had the pins { a bb ccc dddd eeeee f gg hhh iii k ll mmm }.

The following changes were then made to the schematic:

All three figures show pin a at the exact same location, (X,Y) = (0,0) which is the origin point of the symbol. By default, TSG puts the top-most left pin at the origin of the symbol.

Figure 6-1 The Symbol

Figure 6-2 The Symbol after Choosing Replace

After a Replace, only pin a is in the exact same position as the original pins. All other unaffected pins are in new locations for the following reasons:

The modified cellview has all of the unaffected pins {a ccc dddd eeeee f gg hhh k ll mmm} at their original locations. The new pins {wwwwww, zz, ii} have been placed at the bottom of the cellview, outside of the bounding box of the original symbol. The pin and pin names {bb, iii} have been deleted, but the graphic pin line (pin stub) remains to show the position of the pins that were deleted. If necessary, you can delete these graphic pin lines using the symbol editor. Also shown is the note used to describe the changes that were made to the symbol.

Automatically Creating a Cellview from a Pin List

A pin list can be any list of input, output, I/O, or switch pins. You can create a cellview from existing pins, such as those from the basic pin library, or you can create the cellview from new pin names.

To create a symbol cellview from a pin list,

  1. From the view, choose Create – Cellview – From Pin List.
    The Cellview From Pin List form appears.
  2. Type the names of the pins that you want to appear in the automatically created cellview. Separate each pin name with a space.
  3. (Optional) To use a different cellview as the source of the port/pin information, change the Library Name, Cell Name, and View Name fields.
    If either the View Name field or the Tool / Data Type cyclic field does not contain the desired view or conversion function, you must modify the schViewToPinListReg list or the schPinListToViewReg list, both of which are defined in your schConfig.il file, which is described in Virtuoso Design Environment User Guide.
  4. (Optional) To display the cellview in a new window, turn on the Display Cellview button.
  5. (Optional) To edit various cellview creation options, turn on Edit Options.
  6. Click OK.
    When generating a symbol, the Symbol Generation Options form appears if you turned on Edit Options and the cellview is being newly created or replaced.
    If the cellview already exists, a dialog box prompts you to either replace the cellview, modify it (symbol cellview only), or cancel the command.
    The system generates the specified cellview from the pin information you enter on the form.

Automatically Creating a Cellview from an Instance

To create a cellview from an instance,

  1. From the view, choose Create – Cellview – From Instance.
  2. Click an instance in your design window.
    The Cellview From Instance form appears.
  3. Change the options on the form, if needed.
  4. Click OK.
    The system generates the specified cellview from the instance you selected. When you turn on Display Cellview, the system displays the cellview in a new window.

Creating a Cellview from the Canvas (Make Cell)

You can create a new cellview from objects within a specified canvas area by selecting that area, and using the Make Cell command. This process excludes the selection of pins.

To create a cellview from the current window:

  1. In Virtuoso Schematic Editor XL, choose Edit – Hierarchy – Make Cell.
  2. Draw a rectangle on the canvas over the objects to be included. The cursor turns into an icon if an invalid object is selected.
    The Make Cell form appears.
  3. (Optional) Adjust the selection by using the options in the Cut area field.
  4. (Optional) Edit the destination by changing the Library, Cell, and View fields.
  5. Select or deselect the Simplify iterated names check box.
  6. Select or deselect the Place symbol check box. Deselecting it places the new cell directly in the current schematic:
  7. Select or deselect the Remove duplicate symbol pins check box. This is only available when Place symbol is selected.
    If any incorrect selections are made, the form displays an error message and the OK button is unavailable. Resolve any issues, for example, remove any pins from the selection. When all issues are resolved, the OK button becomes available.
  8. Click OK.
    The newly created cell is placed on the canvas.
  9. Click and drag the mouse to move the symbol cell the canvas.
  10. (Optional) Press the 5 key on the keyboard or select Edit – Route Flight to route the connections.

Editing Symbol Generation Options

The Symbol Generation Options form displays the property and attribute settings that the text-to-symbol generator (TSG) uses to generate symbols. The software loads the default form settings from a template file, which you specify using the tsgTemplateType environment variable.

This section discusses the following tasks:

Adding, Changing, and Reordering Pin Names

To add, change, or reorder pin names,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview.
  4. To space pins further apart, add one or more asterisks ( * ) between the pin names in the Left Pins, Right Pins, Top Pins, and Bottom Pins fields.
  5. Click OK.
    This setting results in the following:

Editing Pin Attributes

To edit the attributes of a pin,

  1. From the view, do one of the following:
    • Choose Create – Cellview – From Cellview.
      The Cellview From Cellview form appears.
    • Choose Create – Cellview – From Pin List.
      The Cellview From Pin List form appears.
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. Select List from one of the Attributes cyclic fields.
    The Left, Right, Top, Bottom Pin Attributes form appears.
    The banner title on the form indicates left, right, top, or bottom pin attributes.
  5. Use the Direction cyclic fields to change the direction of the pins.
  6. Use the Pin Graphic cyclic fields to change the graphic of the pin.
  7. Click OK.

Excluding or Including Inherited Connection Pins

To exclude or include inherited connection pins in a symbol view:

  1. Choose Create – Cellview – From Cellview.
    The Cellview From Cellview form appears.
    By default, the software initializes the form with information from the current cellview (in the Library Name, Cell Name, and View Name fields) and the Cellview From Cellview form.
  2. In the To View Name field enter name of the symbol view to be created.
  3. Click the OK button.
    The Symbol Generation Options form is displayed.
  4. Choose whether or not to Exclude Inherited Connection Pins, or name specific inherited connection pins to be excluded.
    Some design flows will require pins with inherited connections to be explicitly shown on the symbol view, whereas other flows will require pins with inherited connection attributes to not be shown. To facilitate both cases the Exclude Inherited Connection Pins section allows you to specify whether all pins with inherited connections are to be excluded during symbol generation, or only a named set. The (Exclude) Only these option will be pre-seeded with the list of all the pins that show inherited connection attributes, and you can manually edit this list.
    See also the tsgExcludeInhConnPins and tsgExcludeInhConnPinsNames environment variables.
  5. Click OK to generate the new symbol view.

Editing Pin Label Defaults

You can use the Labels tab in the Editor Options form to control and override pin label properties such as font and justification settings.

  1. Select Options – Editor to display the Editor Options.
  2. Click the Labels tab.
  3. Amend the options in the Pin Label Overrides section as required.
    You have to first of all check the appropriate Override option, then you need to choose what you want to override this option With. For example, to apply an overbar, you will need to check both the checkboxes associated with this option, one to choose to override the Overbar option, and the other to apply the overbar.
    For more information see the Labels tab in the Editor Options form.

Click the OK button to apply the pin label overrides.

The above pin label options store their values in schematic environment variables, with two variables applicable for each option. One variable controls whether or not to override the associated symbol value, while the other provides the overriding value.

For more information see:

Loading and Saving a TSG Template File

The TSG template file contains the default property and attribute settings that appear on the Symbol Generation Options form. The software loads the TSG template file the first time you use one of the Create Cellview commands to automatically generate a symbol. You use the tsgTemplateType environment variable to specify the TSG template file.

To load or save a TSG template file,

  1. From the view, do one of the following:
    • Choose Create – Cellview – From Cellview.
      The Cellview From Cellview form appears.
    • Choose Create – Cellview – From Pin List.
      The Cellview From Pin List form appears.
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Load / Save.
    The Symbol Generation Options expands to display the template data fields.
  5. In the Load / Save Symbol Template Configuration section, type the path to the TSG template file.
  6. Click Load or Save.
    The system initializes the Load / Save Symbol Template Configuration section of the form with the values from the specified TSG file.
    The software builds all subsequent symbols using the new values.

Editing Symbol Attributes

To edit symbol attributes,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Attributes.
    The Symbol Generation Options form expands to display the symbol attributes options.
  5. Edit the attributes.
    The symbol origin can be specified as topLeftPin, bottomLeftPin, or centerLeft in the Symbol Generation Options form or using the text-to-symbol generator (TSG) origin setting.
    • If the symbol origin is topLeftPin, the top-most, left-most pin is used.
    • If the symbol origin is bottomLeftPin, the bottom-most, left-most pin is used.
    • If the symbol origin is centerLeft, the origin is the middle of the left-hand side of the symbol box.

  6. Click OK.

Editing Symbol Labels

To edit symbol labels:

  1. From the view, do one of the following:
    • Choose Create – Cellview – From Cellview.
      The Cellview From Cellview form appears.
    • Choose Create – Cellview – From Pin List.
      The Cellview From Pin List form appears.
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Labels.
    The Symbol Generation Options form expands to display the label options.
  5. Edit the symbol labels.
  6. Click OK.

Creating a New Label

To create a new label,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Labels.
    The Symbol Generation Options form expands to display the data that can be edited.
  5. In the Label cyclic field, choose new.
  6. Choose the desired Label Choice and other options.
  7. In the Name field, type the name of the new label.
  8. In the Apply To field, specify which objects the label attaches to.
  9. Click Add.
    The new label name is added to the list of labels that will automatically be created during symbol generation.

Deleting Labels

To delete a symbol label from the Label cyclic field,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Labels.
    The Symbol Generation Options form expands to display the label options.
  5. In the Label cyclic field, choose the name of the label you want to delete.
  6. Click Delete.
    The label name no longer appears in the Label cyclic field.

Modifying Label Attributes

To modify label attributes,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Labels.
    The Symbol Generation Options form expands to display the label options.
  5. In the Label cyclic field, choose the name of the label you want to modify.
  6. Make any desired changes to the various label display attributes or label location fields.
  7. Click Modify.
    The label is modified.

Editing Properties

To modify edit properties,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Properties.
    The Symbol Generation Options form expands.
  5. Edit any property.
  6. Click OK.

Creating a New Property

To create a new property,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Properties.
    The Symbol Generation Options form expands.
  5. In the Property cyclic field, choose new.
  6. In the Name field, type the name of the new label.
  7. In the Apply To field, specify which objects the label attaches to.
  8. Click Add.
    The new property name is added to the list of properties that are automatically created during symbol generation.

Deleting Properties

To delete properties,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Properties.
    The Symbol Generation Options form expands.
  5. In the Properties cyclic field, choose the name of the property you want to delete.
  6. Click Delete.
    The property no longer appears in the Properties cyclic field.

Modifying Property Attributes

To modify property attributes,

  1. From the view, do one of the following:
  2. Turn on Edit Options.
  3. Click OK.
    If the symbol cellview to be created already exists, the Create Cellview dialog box appears.
    1. Click Replace.
      The Symbol Generation Options form appears.
      By default, the software initializes the form with information from the current cellview and the Cellview From Cellview form.
  4. In the Symbol Generation Options form, turn on Edit Properties.
    The Symbol Generation Options form expands.
  5. In the Properties cyclic field, choose the property name you want to modify.
  6. Make any desired changes to the various property display attributes or property location fields.
  7. Click Modify.

Specifying Symbol Generator Pin Sorting

Pin sorting is valid only when you create a symbol from a schematic.

When symbols are automatically created, TSG sorts the pins either alphanumerically by pin name (default) or geometrically according to the pin’s relative position in the source schematic view.

To specify how TSG sorts the pins,

  1. From the view, choose Options – Editor.
    The Editor Options form appears.
  2. In the Command Controls section of the form, set the Symbol Generator Pin Sorting option to alphanumeric or geometric.
  3. Click OK.
    Automatic symbol generation now uses the specified pin sorting method.
    You can change the default (alphanumeric to geometric) by editing the ssgSortPins environment variable. The system uses this variable when you choose Options – Save Defaults. It is also available as arguments to the schGetEnv and schSetEnv procedural interface SKILL functions.

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