Virtuoso Layout Editor User Guide -- 1. Virtuoso Layout Editor Overview

Virtuoso Layout Editor User Guide, Product Version 5.0

1

Virtuoso Layout Editor Overview

This chapter contains these topics:

Using the Virtuoso Layout Editor

About the Command Interpreter Window

About the What's New Window

Starting the Layout Editor

Using the Library Browser to Open Files

Using the Open File Form to Open Files

Overview of Cellviews

The Parts of a Virtuoso Layout Editor Design Window

Making Cellviews Editable

Using the Virtuoso Layout Editor

You use the Virtuoso^® layout tools to prepare custom integrated circuit designs. The layout editor is the base editor in the Virtuoso set of tools.

The layout editor lets you perform the following tasks:

Create and edit polygons, paths, rectangles, circles, ellipses, donuts, pins, and contacts in layout cellviews

Place cells into other cells to create hierarchical designs

Connect a pin or group of pins in a net internally or externally

Automate each stage of the design task using the Virtuoso XL Layout Editor

Create special parameterized cells (called pcells) containing data that you want to modify quickly or that you want to set with Cadence^® SKILL language commands

About the Command Interpreter Window

The Command Interpreter Window (CIW) is the first window that appears when you start a Cadence design framework II (DFII) workbench. The CIW is used in these ways:

To display menus containing commands and tools for general, non-tool-specific operations

To enter SKILL commands

To display messages and warnings

About the What's New Window

There are two What's New windows displayed by layout editor.

The What's New in 5.0.0 window is displayed when the CIW is opened. It describes the general changes made to the Design Framework II between releases.

The About What's New window is displayed when a cellview window is opened. It highlights new features and enhancements in each release of the Virtuoso design environment.

If you do not want these windows to open each time you display the CIW or a cellview window you may stop them from opening.

Turning Off the What's New Window

To turn off the Command Interpreter Window (CIW)'s What's New in 5.0 window, do one of the following:

Choose the Edit - Off at Startup from the Edit pulldown menu on the What's New in 5.0.0 window

Add the following line to your .cdsenv file

ddserv showWhatsNew string "5.0"

To turn off the Virtuoso Layout Editor's About What's New window, do one of the following:

Choose the Edit - Off at Startup from the Edit pulldown menu on the About What's New window

Add the following line to the .cdsenv file:

layout showWhatsNew string "5.0"

You can display these windows at any time (even if you have turned off the startup display) by choosing Help - What's New from the CIW or by choosing Help - What's New from a layout editor window.

Editing the What's New Window

The About What's New Window text is a concatenation of .txt files located at your_install_dir/tools/dfII/etc/tools/layout. If you modify the text of any of the .txt files, you can rebuild the Whatsnew.txt file in Unix (you can change the order of concatenation or even add your own files) The following is a C shell example:
rm -f Whatsnew.text
cp layout.txt Whatsnew.txt
foreach file ("layout.txt" "vxl.txt")
echo ""   >> Whatsnew.txt
echo ""   >> Whatsnew.txt
cat $file >> Whatsnew.txt
end
Starting the Layout Editor

To start the Virtuoso Layout Editor software, you must type the name of an executable in an xterm window. Basic layout editor workbench executable names include

layout - includes the layout editor, Diva^®interactive verification product , plotting, and physical translators

layoutPlus - includes all of the above, plus the Virtuoso Compactor and Virtuoso XL

You may have other executables that start the layout editor, depending on what you have installed.

For example,

To start the layout editor and the interactive verification products, type

layout &

To start the layout editor with the compactor in the Tools menu, type

layoutPlus &

The optional ampersand (&) starts the Cadence software in the background of this window. This means you can use the xterm window for other tasks while the layout editor software is running.

After you type the appropriate command, the window displays a list of the Cadence software products it is checking out. The software is finished loading when the CIW appears.

Running Layout Editor in 64-Bit

To run 64-bit software,
Install the 64-bit version of software to the same location as your 32-bit software. Ask your Cadence software administrator to install it, if necessary.
Verify that all required patches are installed by running the System Configuration Checking Tool script, checkSysConf. This script is in your local installation of Cadencesoftware, at the following location:
your_install_dir/tools/bin/checkSysConf IC500
IC500 is a parameter expected by the script.

The System Configuration Checking Tool is also available on the SourceLink^SM online customer support system.

All required patches must be installed for the 64-bit executables to work correctly.
Set the environment variable CDS_AUTO_64BIT {ALL|NONE|"list"|INCLUDE: "list"|EXCLUDE:"list"}to select 32-bit or 64-bit executables.

ALL

Invokes all applications as 64-bit, where available. The list of executables available are in:
your_install_dir/tools/bin/64bit

NONE

Invokes all applications as 32-bit.

"list"

Invokes only the executables included in the list, if available, as 64-bit. list is a list of case-sensitive executable names delimited by comma(,), semi-colon(;), or colon(:).

"INCLUDE:list"

Invokes all applications in the list as 64-bit, where available.

"EXCLUDE:list"

Invokes all applications as 64-bit, where possible, except the applications in the list.

Examples:
setenv CDS_AUTO_64BIT "pipo,layout.exe"
setenv CDS_AUTO_64BIT "EXCLUDE:si"
If you do not set this environment variable then the 32-bit executable is invoked by default.

All 64-bit executables are controlled by a wrapper executable. The wrapper invokes the 32-bit or 64-bit executables depending on how the CDS_AUTO_64BIT environment variable is set, or whether the 64-bit executable is installed. The wrapper also adjusts the paths before invoking the 32-bit or 64-bit executables.
Launch the executables through the wrapper only.

Example:
your_install_dir/tools/dfII/bin/layout
The wrapper you use to launch the executables is in your_install_dir/tools/dfII/bin.

The 32-bit executables are found in your_install_dir/tools/dfII/bin/32bit.

The 64-bit executables are found in your_install_dir/tools/dfII/bin/64bit.
Do not launch the executables directly from your_install_dir/tools/dfII/bin/64bit or from your_install_dir/tools/dfII/bin/32bit directory.

Using the Library Browser to Open Files

You can open the Library Browser from forms that contain a Browse button. When you need to specify a library name, the Library Browser lets you look though the libraries specified in your cds.lib file and set the library, cell, and view names for the form that opened it.

      To open the Library Browser, click on the Browse button in a form.

Using the Library Browser

You can use the browser to choose the library, cell, and view for the form that opened the browser.

To choose a library,

      In the Library list, click on the library you want.

The library name appears above the list, and the other lists are updated to reflect the categories, cells, and views contained in that library.

To choose a cell or view,

      Click on the cell or view name you want.

The cell and view names appear above the lists and in the form that opened the browser.

Using Categories

You can categorize cells in a library so that you do not have such a long list in the Library Browser. Categorizing cells is also a useful way to keep track of groups of cells that describe specific sections of your design. You can

Use the Library Manager to create cell categories

Show categories in the browser

Remove categories in the browser

To show the cell categories,

      Set the Show Categories button on.

To remove the cell categories,

      Set the Show Categories button off.

Using Filters

You can use categories or the View Filter By form to specify which cells and views you want to see.

      To filter the cell and view lists by a category, click on an entry in the Category list.

To filter the cell and view lists using the View Filter By form,

Click on the Filters button in the browser.

In the View Filter By form, type characters and wildcards in the text field and click OK.

The form is closed and the browser lists are filtered and updated.

About Libraries

You store cells such as inverters, NAND gates, or NOR gates in a library. Each library keeps a catalog of all cellviews together with the path to the data files. The library is associated with files that define common information such as mask layer names and design rules.

There are two types of libraries: design and reference.

A design library contains the cells and views you are working on. You and your design team might share the same working design library.

A reference library contains well-verified cells and views with read-only privileges. Reference libraries are frequently shared within a group or company.

Using Reference Libraries

A reference library contains master cells that other designs use. These master cells are protected from editing so they remain consistent between designs.

To use reference libraries, you

Create a reference library and set its file access permissions so that other design groups can read its cells

Add the reference library path to each user's cds.lib file

Using the Open File Form to Open Files

The Open File form lets you open a cellview in a design window. You can open a layout cellview in read-only mode without a license, but you do not have any editing capabilities without a license.

There are two ways to open cellviews.

In the layout editor cellview window, the Window - Open command closes the current cellview and replaces it with a new cellview.

In the CIW, the File - Open command opens another window containing the new cellview.

The Open File form is documented in the Design Framework II Help manual.

Opening a Cellview

To open a cellview,

Choose either Design - Open from the cellview menu banner or
File - Open from the CIW.

In the Open File form, choose the library from the Library Name field.

The Cell Names list changes to reflect the cell names in the selected library.

Choose one of two ways to select a cell name:

Click on a Cell Name in the list

Type a name in the Cell Name field

In the View Name field, choose a view name.

Click OK.

If you are opening a managed file, you might be asked if you want to check out the file.

Creating a New Cellview

To create a new layout cellview,

Choose File - New - Cellview from the CIW.

In the Create New File form, choose the library from the Library Name cyclic field.

Type a cell name in the Cell Name field.

Type layout in the View Name field.

To set Tool, do either of the following:

Press Tab to automatically choose Virtuoso

Choose Virtuoso from the Tool cyclic field

Click OK.

If you want to create a managed file, you need to check in the file after you close it.

You can have the View Name and Tool fields automatically update one another by setting specific environment variables. For information about these environment variables, see the deNew SKILL function documentation in Cadence Design Framework II SKILL Functions Reference.

About the Create New File Form

The Create New File form lets you create a new cellview.

The Create New File form is documented in the Design Framework II Help manual.

Saving a Cellview

As you edit a cellview, your data exists only in virtual memory. You need to periodically save your data to disk. The Save command copies the design from virtual memory to disk.

      To save your cellview edits to disk, do one of the following:

Choose Design - Save.

Press F2.

Click on the save icon in the icon menu.

About the Save As Form

The Save As command lets you save the current cellview to disk with a new name.

Library Name sets the name of the library to which you want to save the new cellview.

Cell Name sets the name of the cell for the new cellview.

View Name sets the view name. For the layout editor, this is usually layout.

Saving a Cellview Under a Different Name

To save a cellview under a different name,

Choose Design - Save As.

In the Save As form, enter the library, cell, and view names you want to use.

Click OK.

A copy of this cellview is created under the library, cell, and view name specified. The layout editor continues to edit in the original cellview rather than switching to the new cellview.

Depending on how your check-in defaults are set, you might be asked if you want to check in the file. If you are not asked and you want to create a managed file, you need to check the new file in manually.

Closing a Cellview

When you are finished editing a cellview, you can close it.

To close a cellview,

Choose Window - Close [Control-w].

If you edited the cellview and have not yet saved it, a dialog box warns you that you have not saved your edits.

To save your edits to disk, click Yes.

If this is a managed file, you might be asked if you want to check in the file.

Quitting After Saving All Edits

After you have saved all your edits to cellviews and you want to quit the Cadence software,

Choose File - Exit from the CIW.

The Exit dialog box appears.

Click Yes.

All the Cadence software windows close.

If there are any checked-out managed files, you might be asked if you want to check in the file.

Quitting and Saving Edits

If you have not saved all edits to cellviews before you choose the Exit command, you are prompted to save data as you quit.

Choose File - Exit from the CIW.

Click OK in the Exit dialog box.

Fill in the Save Cellviews form as follows.

Click OK.

All the Cadence software windows close. If there are any checked-out managed files, you may be asked if you want to check in the file.

Overview of Cellviews

You create the physical layout of a chip design in a layout cellview.

A cell is the basic design object from which you build a chip or system. Each cell can include layout, schematic, and symbolic data representing a part of your chip design.

Different types of cell data are displayed in different views. For example, you can create layout, schematic, and symbolic views of an inverter. So a layout cellview is the layout view of a cell.

As shown below, you edit or create a layout of your nand2 cell with the layout editor by opening a layout cellview.

The Parts of a Virtuoso Layout Editor Design Window

The following is an example of a Virtuoso Layout Editor window.

Window Title

The top of the window contains information about the cell you are viewing.

Status Banner

The status banner displays information about the cursor, selection, points, and command.

Menu Banner

The menu banner displays the layout editor menus. You can click on an item in the banner to display a menu of commands.

Icon Menu

The icon menu appears on the left side of design windows. You can start common commands quickly by clicking on an icon. To see the command name, move the cursor over the icon. In read-only mode, the editing icons are not displayed.

Cursor and Pointer

Use the mouse cursor to enter points or select design objects. Use the pointer to choose menu items or options in command forms.

Design Area

In the design area, you create and edit objects: paths, polygons, and other shapes for your physical layout. You can turn the grid on and off in the design area. You use the grid to help create objects.

Mouse Settings

The mouse settings line shows what clicking the left, middle, or right mouse button does for the current window and command state.

Prompt Line

The prompt line shows instructions from the current command.

Making Cellviews Editable

To make a cellview editable,

      Choose Design - Make Editable

You can change a cell so it is read only (you cannot edit it).

To make a cellview read only,

      Choose Design - Make Read Only

When the cellview is set to read only, this command is replaced by Design - Make Editable, which, when chosen, returns the cellview to edit mode. Design - Make Editable works only if the UNIX permissions on the file are set to enable write.

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`ALL`	Invokes all applications as 64-bit, where available. The list of executables available are in: `your_install_dir/tools/bin/64bit`
`NONE`	Invokes all applications as 32-bit.
`"list"`	Invokes only the executables included in the list, if available, as 64-bit. `list` is a list of case-sensitive executable names delimited by comma(,), semi-colon(;), or colon(:).
`"INCLUDE:list"`	Invokes all applications in the list as 64-bit, where available.
`"EXCLUDE:list"`	Invokes all applications as 64-bit, where possible, except the applications in the list.