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Exporting Design Data

The remainder of the Export Control panel is used to initiate writing of a design data file to disk. A number of options are available when writing a file with this panel. Unlike the settings described above, these settings apply only to files created with this panel.

The currently selected tab at the top of the panel specifies the output format to use. Details of the format selections are described below.

GDSII
This choice will create a GDSII (Stream) file of the current editing cell and its descendents. Upon pressing Write File, the name of the file for the GDSII output is requested from the user. The user can add a ``.gz'' extension, or remove the extension if already present, to control whether or not gzip compression is used. The GDSII layer numbers and datatypes are as given in the technology file.

Xic will ensure that cell names included in the GDSII file conform to the standard (upper and lower case, digits, `_', `$', `?' only, up to 32 long in GDSII Release 3).

All layers that are to be written to the GDSII file should have a GDSII output mapping specified. This can be added to the technology file with a text editor, or interactively with the Edit Tech Params button in the Attributes Menu. By default, a layer needed for output that does not have a mapping will terminate the operation. However, if the Skip layers without Xic to GDSII layer mapping check box in the GDSII page of the Export Control panel is checked, or equivalently the variable NoGdsMapOk is set (with the !set command), then such layers will be ignored (producing no output).

OASIS
This choice will create an OASIS file of the current editing cell and its descendents. Upon pressing Write File, he name of the file for the OASIS output is requested from the user. The layer numbers and datatypes are as given in the technology file. These are the same as for GDSII.

All layers that are to be written to the OASIS file should have a GDSII output mapping specified. This can be added to the technology file with a text editor, or interactively with the Edit Tech Params button in the Attributes Menu. By default, a layer needed for output that does not have a mapping will terminate the operation. However, if the Skip layers without Xic to GDSII layer mapping check box in the OASIS page of the Export Control panel is checked, or equivalently the variable NoGdsMapOk is set (with the !set command), then such layers will be ignored (producing no output).

CIF
With this choice, the current editing cell and its descendents will be written to a CIF file. Upon pressing Write File, the user is prompted for the name of the file for CIF output.

The extension syntax used for cell name specification and labels, and whether the layer directives use indexing or names, are settable with the CifOutStyle variable and/or the CIF page menus in the Export Control panel.

CGX
With this choice, the current editing cell and its descendents will be written to a CGX file. Upon pressing Write File, the user is prompted for the name of the file for CGX output. The user can add a ``.gz'' extension, or remove the extension if already present, to control whether or not gzip compression is used.

Xic Cell Files
This choice will unconditionally write to native-format files the hierarchy of the current editing cell. It can be used to transform a hierarchy input from a supported archive format file into Xic native format.

When Write File is pressed, the user is given the option of setting the directory which will receive the created files. If no directory is given, the files will be created in the current directory. While the prompt is in effect, a pop-up containing a tree listing of the directory hierarchy rooted in the current directory appears. The user can select a directory in the listing, or type the directory path on the prompt line. If a directory path is given and the final directory does not exist, it will be created, if possible. Pressing Esc will abort the operation.

After the cell writing is complete, a library file will be written in the current directory, given the name of the top-level cell suffixed with ``.lib''. This file will have references to each of the new files created, with the top-level cell name listed first, and the others listed in alphabetical order. This library may be placed in the search path to gain access to the new files through the library mechanism, in which case the directory containing the files need not be in the search path.

The remaining controls are described below.

Cell Name Mapping
This group of controls manages the cell name aliasing feature. This does not apply to native cell file output.

A subset of the windowing operations is available. From this panel, windowing is only available when flattening.

Conversion Scale Factor
The Conversion Scale Factor provides an entry area where a scale factor to be applied during the write operation can be entered. Values of 0.001 through 1000.0 are acceptable. This will apply to output initiated from this panel only.

Don't convert invisible layers
There are separate check boxes that apply to physical and electrical modes. When active, only layers that are currently visible, as selected with button 2 in the layer table, will be written when writing output using this panel. This is the method by which certain layers can be eliminated from generated output. When this button button is not active, all Xic layers will be written.

This feature can also be enabled by setting the variable SkipInvisible with the !set command.

Strip For Export
When the Strip For Export button is active, converted output will contain physical data only, and will contain no Xic extensions. Further, the Strip For Export check box implicitly enables the same functionality as Include Library Cells (see below), so that the file will not contain unresolved library cell references. Additionally, parameterized cell and standard via sub-masters will be included in output, as if the corresponding check boxes were also checked. The Strip For Export box should be checked when creating a file for use in generating photomasks. Note that the electrical information can never be recovered from a stripped file.

Within Xic, archive file representations consist of two sequential records in each file. The first record is the physical information, and the second record contains the electrical information. These files should be compatible with other CAD systems, as these files are generally expected to have only one record, and consequently the electrical information may be ignored. However, one should not count on this. When the Strip For Export button is active, Xic will convert only the physical information when explicitly (i.e., using the operations from the Export Control panel, and not the Save and Save As buttons) converting to an archive format. The Strip For Export setting also applies to the ToArchive, script function. This creates a file which should be an absolutely conventional physical layout file.

This mode can also be enabled by setting the boolean variable StripForExport with the !set command. The variable tracks the state of the check box.

Include Library Cells
When checked, cells with the LIBRARY flag set are written to the output file. Ordinarily, these cells are expected to be resolved through the library mechanism and are not written to the output file.

This tracks the state of the WriteAllCells variable.

Include parameterized cell sub-masters
When this check box is checked, output saved to disk files will include sub-master cells. Ordinarily, sub-master cells are not included, as they will be re-created when the file is read. However, when exporting to a system that does not support the pcells in use, the sub-masters must be written if the file is to have any value. With the sub-masters present, the cells/instances will look like normal cell placements.

This applies when writing all output, except when using the Save and Save As buttons in the File Menu, and the equivalent text accelerators and including the prompts when exiting the program. It is also ignored when using the Save script function.

Xic native pcells are only supported in Xic. OpenAccess-based pcells might be supported by other systems, that is certainly the intent of the Ciranova PyCells. Even if another system supports the OpenAccess PyCells, it may not have the logic to rebuild the pcells coming from a GDSII or other file source. In that case one will probably have to ship the OpenAccess library files.

The StripForExport variable and the equivalent check box will have the same effect when set.

The PCellKeepSubMasters variable tracks the state of this check box.

Include standard via cell sub-masters
When checked, standard via cell sub-masters are included in the output file. This will be required when sending output to another system, as this implementation is specific to Xic. An exception may be systems that share an OpenAccess database with Xic. If the cells are written to the OpenAccess database, the standard vias should translate properly, and be recognized by other tools (e.g., Virtuoso) that share the database.

This applies when writing all output, except when using the Save and Save As buttons in the File Menu, and the equivalent text accelerators and including the prompts when exiting the program. It is also ignored when using the Save script function.

The StripForExport variable and the equivalent check box will have the same effect when set.

The ViaKeepSubMasters variable tracks the state of this check box.

Consider ALL cells in current symbol table for output
When checked, all cells in the current symbol table, not just the hierarchy of the current cell, will be output as if they were part of the hierarchy. The usual filtering of library and sub-master cells is retained. The resulting file may have multiple top-level cells.

The write is actually initiated with the Write File button. The name of the output file will be prompted for on the prompt line. The Dismiss button retires the panel.

Cell files can also be written to disk using the Save and Save As commands in the File Menu. However, if scaling or other options available in this panel are required, the file must be generated from this panel.

When generating an archive file and an error occurs. the archive file will normally be deleted. However, if the variable KeepBadArchive is set (with the !set command) the output file will be given a ``.BAD'' extension and retained. This file should be considered corrupt, but may be useful for diagnostics.


next up previous contents index
Next: The Advanced OASIS Export Up: The Export Cell Data Previous: CGX Settings   Contents   Index
Stephen R. Whiteley 2017-11-08