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The Convert Menu: Data Format Conversion

In addition to the native cell-per-file format, Xic has interoperability with the archive file formats listed below. These file types can be read into Xic directly with the Edit command, and generated with the Save As command. The Convert Menu provides for setting format-specific conversion parameters, and contains other conversion commands.

Under Unix/Linux, except for the ``Solaris'' distribution, files are opened in 64-bit offset mode. This enables files larger than 2Gb to be processed.

Native Xic cells use a CIF-like ascii format, with one cell per file. This is the default format used by Xic, but is not particularly efficient with respect to input/output speed and disk space.

In addition to the native cell-per-file format, Xic supports a number of archive formats, which can contain one or more cell descriptions.

GDSII
The GDSII (Stream) format is an industry-standard binary file format for cell hierarchies and libraries. Xic can read Format Release 3-7 files, and write either Format Release 7 or Format Release 3 (which is readable on systems supporting Format Release 3-7). GDSII files that have been compressed with the GNU gzip program or equivalent can be read directly, and similarly compressed GDSII output can be generated by Xic.

CGX
The CGX (Computer Graphics eXchange) format is a public-domain binary archive format developed by Whiteley Research Inc. Similar in structure to GDSII, the advantages are more efficient data representation for reduced file size and ease of parsing for faster read/write. Although presently available only in Whiteley Research products, it is anticipated that the format will eventually be supported by other vendors. CGX files that have been compressed with the GNU gzip program or equivalent can be read directly, and similarly compressed CGX output can be generated by Xic.

OASIS
The Open Artwork System Interchange Standard (OASIS) is a new standard for mask layout data being developed by the SEMI organization. This is a binary format which features more compact representation and thus smaller files than GDSII.

More information is available from www.wrcad.com/oasis.

WARNING: This is a prototype capability built from SEMI Draft Document 3626 2003/04/23 but adheres to the final published specification. The current implementation and documentation are preliminary.

That being said, the present status of OASIS support in Xic (and XicII) is fairly complete:

  1. Xic can read any spec-conforming OASIS file.
  2. OASIS output from Xic is readable by any other spec-conforming tool.
  3. Exceptions to the above are bugs, please report!

CIF
The CIF format, though a bit archaic, is still popular. Xic supports a number of selectable dialects and extensions.

The Convert Menu entry brings up a submenu containing commands which perform explicit translations and other manipulations and diagnostics.

The table below lists the commands found in the Convert Menu, and gives the internal name and a brief description.

Convert Menu
Label Name Pop-up Function
Export Control exprt Conversion - Export Export files
Import Control imprt Conversion - Import Import files
Convert convt Conversion Direct conversions
Read Into Current readc none Import data
Text Editor txted Text Editor Text edit cell file
Edit Parameters adgds Conversion Parameter Editor Edit GDSII layer map

The Edit command in the Edit menu can be used directly to read files in the supported formats for editing. When a cell is written to disk, it is by default written in the format of origin, though a format change can be coerced in the Save As command by supplying a file extension. Thus, there are alternatives to using many of the commands in the Convert Menu.

During a conversion, a log file is written by the converters. This file contains a record of messages emitted during the conversion. If during a conversion an error or warning message is emitted, a file browsing window containing the log file will appear when the conversion is complete, though this can be suppressed by setting the NoPopUpLog variable. These messages also appear on the prompt line during the conversion. The file browser is a read-only version of the text editor window, and has a number of associated keyboard commands, including word searching. See 1.4 for a listing of these commands.

On GDSII and OASIS input, if there is no specified mapping for a given layer and datatype, an attempt is made to map to the existing Xic layers, and if that fails, a new layer is created.

When reading CIF, layer names are matched to those defined in the current technology in a case-insensitive mode. This differs from native and CGX file types, which use case-sensitive matching. Layers found in the file which do not match any in the technology are created, using default parameters.



Subsections
next up previous contents index
Next: Cell Name Aliasing Up: xicmanual Previous: The Edit Layers Button:   Contents   Index
Stephen R. Whiteley 2006-10-23