Exporting IFF Schematic Files from DFII

This chapter describes the procedure for exporting an Intermediate File Format (IFF) schematic file from the Cadence CIW.

IFF Schematic Export from DFII

Before attempting to export an IFF file from DFII, refer to Before Using the IFF Translators.

The basic procedure for exporting an IFF schematic file from DFII can be broken down into several simple steps:

1. Accessing the Framework Output Transfer Form
2. Specifying the File Name and Setting Export Options
3. Completing the Export

Exporting an IFF Schematic File

This section describes the procedure for exporting an IFF schematic file from Design Framework II using the IFF Translator from the Cadence CIW. It is a recommended practice to export only design schematic information. This implies excluding everything else from the export process such as simulation control blocks as well as any other elements that do not map directly to Advanced Design System. Such elements should exist at the top cell (symbol) view. To avoid complications, descend one level into this symbol view before beginning the export process.

The menu items described in this section are only available after the .cdsinit file has been configured for an Intermediate File Format file transfer between DFII and ADS. For more information, refer to Before Using the IFF Translators.

Accessing the Framework Output Transfer Form

To access the schematic export tools, launch your export from the Cadence Command Interpreter Window (CIW).

1. In a terminal window, change to the appropriate directory.
2. Run Cadence by typing the appropriate command (typically icms or msfb ). The Cadence Command Interpreter Window (CIW) appears.
   

Cadence CIW Window

1. From the Cadence CIW, choose IFF > Export IFF . The Framework Output Transfer Form appears.
   

Specifying the File Name and Setting Export Options

In the Framework Output Transfer Form , specify the file name, enter the library and output cell names and supply other basic information needed by the translator.

Output File Name

In the Output File Name field, enter the full path and file name of the IFF file generated in Virtuoso Schematic Composer that you want to export into Advanced Design System.

Output Library Name

In the Output Library Name field, enter the name of the library containing the cell you want to export. If you are exporting the entire library, enter the name of the library you want to export. The library name will default to the library name of the cell that was in the last active schematic window.

Output Cell Name

In the Output Cell Name field, enter the name of the Cadence cell that you want Cadence to export. The cell name will default to the cell name of the cell that was in the last active schematic window.

Type of Hierarchical Transfer

There are four choices available from the Type of Hierarchical Transfer section of the Framework Output Transfer Form . For design exports, it is recommended that the second button is selected so that the output IFF file contains only hierarchical blocks of the design and none of the library parts. For detailed information on each of the selections, refer to the descriptions below.

The design Only When this option is selected, only the schematic and symbolic views of the top-level design are exported. No hierarchy is translated. For this option to function properly, all of the instances used in the design must have library elements that already exist in one of the libraries available in ADS.

The design and its parts found in the same library When this option is selected, the schematic and symbolic views of the open design are exported. Additionally, all schematic and symbolic views of cells (included in the cell) in the same library as the open design are output into the IFF file. Any instance of reference library cells (that is, cells from a library other than that of the open design) are not exported. For this option to function properly, all of the cells placed from other libraries must already exist in one of the libraries available in ADS.

The design and its parts except those found in HP_excludeLibs When this option is selected, the schematic and symbolic views of the open design are exported. Additionally, the schematic and symbolic views of any instance encountered in the design are exported unless the instance belongs to a library appearing in the HP_excludeLibs list. For this option to function properly, any cell placed from a library listed in HP_excludeLibs must already exist in one of the libraries available in ADS.

Caution The design and its parts except those found in HP_excludeLibs is the default setting for this form. Exporting with this option set may cause simulation problems in Advanced Design System and should be avoided. This setting is typically used for establishing a reference library in ADS.

The entire library When this option is selected, the schematic and symbolic views of the open design are exported. The schematic and symbolic views of all other designs in the library are also exported, whether the cells have been placed in the open design or not. Nothing from any other library is exported.

This option is provided so that reference libraries from Cadence can be moved into Advanced Design System. After the file has been exported, it will still be necessary to perform simulation setups on all components. The steps required to build a functional ADS version of any Cadence reference library is complex and currently undocumented as discussed in Understanding Component Library Requirements. For information on creating compatible component libraries for use with IFF, refer to Getting Help.

Simulator to use for pin ordering

The Simulator to use for pin ordering field is used to designate the simulator to use for component pin ordering. Enter (spectreS) since ADS models are typically translated from Spectre subcircuit models. The default value is (spectreS) .

Export standard connectors as components.

The IFF translator normally converts ports and grounds to an Advanced Design System equivalent. When this option is selected, ports and grounds are not translated to ADS equivalents. This requires that the Cadence port or ground be transferred as a library component. When the Export standard connectors as components option is selected, all standard connectors are translated as components in ADS. The default setting for this option is deselected.

Exclude these libraries in Hierarchical Export

Components listed in the Exclude these libraries in Hierarchical Export field are not hierarchically exported. Thus, no symbol or schematic information is created for these components. Instance data is still generated.

Do not export these properties when encountered

The properties listed in the Do not export these properties when encountered field are not included in symbols or instance records. This option is useful for suppressing Cadence system properties.

Export Component Parameter Modifiers from CDF

When the Export Component Parameter Modifiers from CDF option is selected, component parameter modifiers contained in the Cadence Component Description Format (CDF) are exported to Advanced Design System. The default setting for this option is deselected.

Completing the Export

After you have completed the Framework Output Transfer Form , click Apply in the Framework Output Transfer Form to save your settings or Defaults to retain the default settings. You can also click Cancel to abort the export operation. Click OK to begin the translation.

After the translation begins, all export log information is displayed in the Cadence Command Interpreter Window (CIW). One of the log lines will display what was created. Any warnings or error messages encountered during the translation are also displayed in the log messages.

Additional Export Options

This section describes some of the additional options available from the Cadence CIW IFF command menu.

Export library data for formsets

This section describes the selections available from the Export library data for formsets dialog box. When the menu command IFF > Export cyclic data for formsets is selected from the Cadence CIW, the Export library data for formsets dialog box appears.

Note This dialog box was created exclusively for library customizing and should not be used without consulting Agilent Technologies Solution Services. For more information, contact your Agilent Technologies sales representative.

Data File Name

The data file is a Cadence file that can be utilized by the Library Translator, a custom tool available from Agilent Technologies Solution Services. The file name entered into this field contains information about all of the cyclic fields for a given library. Do not enter a file extension when entering the file name as two separate files are created during the export. One will have a .dat extension, which is a semi-binary representation of the cyclic fields, which will be used in the Library Translator so that a you can choose what formset a Cadence parameter will utilize. The second file will have a .ael extension that will contain the ADS Application Extension Language (AEL) code necessary to create the needed forms and formsets for the ADS environment.

Library Name

This field is used to enter the name of the library that you want to export cyclic field data from.

Prefix all form names with

In some cases, it may be necessary to prefix the form names with the library name or the library and cell name. This field enables you to designate a prefix in order to generate unique form and formset names.

As an example, if you were exporting data from the analogLib and generic_foundry libraries, both of these libraries contain a cell named npn that has a parameter called region . In analogLib , the values are on and off . In generic_foundry , the values are on , off and reverse . When the formsets are generated, if the formset name is npn_region , the analogLib and genericLib components could not be used simultaneously in ADS as formsets would overlap. It is necessary to prefix the formset names so that they will be unique. This is done by specifying analogLib as the prefix when exporting the analogLib library, and specifying generic_foundry when exporting the generic_foundry library. Now, the formset name for analogLib would be analogLib_npn_region , and the formset name for generic_foundry would be generic_foundry_npn_region .

Configure IFF Variables

This section describes the selections available from the Configure IFF Variables dialog box. When the menu command IFF > Configure IFF Variables is selected from the Cadence CIW, the Configure IFF Variables dialog box appears.

Scaling Factor for Cadence to Target System

When transferring cells from Cadence to Advanced Design System, the Cadence symbol sizes tend to be about one half the size of ADS symbol sizes. This results in poor quality schematic resolution. This scaling factor can be used during an export to improve the resolution by using the default value (200) to make all Cadence symbols and schematics twice the size in ADS. Additionally, during an import, all values are reduced to 50% of their original size.

Exclude these libraries in Hierarchical Export

This field enables you to specify a set of libraries that should not have symbols and schematics included in hierarchical exports. The primary purpose of excluding libraries is that when a reference library is used in Cadence, a duplicate of that library must be created in ADS. The duplicate library contains all of the simulation setup data that is not contained within the Cadence library. If the components from the reference library are output into the IFF file, new components without the necessary simulation setups are created in ADS and the design will not simulate.

As an example, lets say that you have a design in a library mylib called myschematic . Within this design, you place an instance of the cell res from the analogLib library. If you specify analogLib in the Exclude these libraries in Hierarchical Export field, and then proceed to perform a full hierarchical export, the symbol for mylib myschematic is exported and the schematic mylib myschematic is created in the IFF file. However, the symbol for analogLib is not placed in the IFF file because it has been designated as being excluded. If analogLib is not specified in the exclude library list, the symbol for analogLib res is created in the IFF file. Note that if analogLib res is created as a symbol, it is up to you to create the proper simulation setup for the component when it is imported into ADS.

Note This field matches the field found on the IFF export dialog.

Do not export these properties when encountered

This field is provided primarily so that Cadence system properties can be omitted from the IFF export if desired. It's main purpose is to avoid clutter in the property fields of instances. You can decide if you want to omit properties that are not necessarily Cadence system properties, or whether you want to have the properties translated.

Export standard connectors as components

This checkbox enables you to specify how to translate connectors. A connector in this context is defined as a pin or a ground component. In Cadence, this means basic ipin , basic opin , basic iopin , analogLib gnd , analogLib gnda , and analogLib gndd . When any of these components are encountered, and this checkbox is deactivated, the components are converted into the ADS equivalent components (either Port for the basic pins or Ground for the analogLib ground component). Because the ADS components are shaped differently from the Cadence components, it may be more desirable to transfer the components without converting them into ADS equivalents ensuring that the schematic will look identical to its Cadence representation. Activate this checkbox if you want to translate your connectors as Cadence components.

Note The analogLib Design Kit for ADS contains all of these components and they are already setup to function properly as the default ADS connectors. If you want to activate this checkbox, it is recommended that the factory generated analogLib Design Kit be used in the ADS environment.

Framework Software Version

This section describes the Framework Software Version dialog box. When the menu command IFF > About is selected from the Cadence CIW, the Framework Software Version dialog box appears.

This dialog box displays:

• The IFF for Cadence version number.
• The Agilent Technologies Copyright information.
• Revision information for the init.il , cdsin.il and cdsout.il files.
• Information on where to obtain the latest version of the mdsinit.il file.
  Use this information when contacting Agilent Technologies for technical support.