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File Format Selection

A drop-down menu at the top of the panel selects one of four types of input:

Layout File
The source file is a normal layout file in one of the supported archive formats. The various input file formats are recognized automatically.

Cell Hierarchy Digest Name
Input will be read through a Cell Hierarchy Digest, as listed in the Cell Hierarchy Digests panel.

Cell Hierarchy Digest File
Input will be read through a Cell Hierarchy Digest found in a file on disk, as was generated from the Save button in the Cell Hierarchy Digests panel.

Native Cell Directory File
Input will consist of native cell files found in a given directory. All cells found in the directory that do not have a ``.bak'' file extension or duplicate a device library name, regardless of any hierarchical relationship or lack thereof, will be translated and concatenated into an archive file.

When translating CIF files, or from native cell files using Native Cell Directory, four-character CIF-style layer names found in the input must be mapped to layer and datatype numbers when output is in GDSII or OASIS format. If the layer exists in the layer table and the GDSII StreamOut parameter has been set, that mapping will be used. The StreamOut parameter is normally set in the technology file, but can also be set from the Tech Parameter Editor from the Edit Tech Params button in the Attributes Menu. When not mapped via an existing layer in the layer table, if the CIF layer name is a four-digit hex number, it will be interpreted as ``LLDD'' to obtain the GDSII layer and datatype numbers. If not in this form, a new layer number and datatype will be internally generated, using the UnknownGdsLayerBase and UnknownGdsDatatype variables.

When using Native Cell Directory, the directory can contain an alias file (see 14.3) that can be used to map native cell names to new names in the output. This file must be named ``aliases.alias'', and is never generated by Xic. It must be prepared by hand or some other means if needed. Each line contains the native cell name followed by the name to use in output, separated by white space. The Read Alias check box in the Format Conversion panel, or (equivalently) the InUseAlias variable must be set in order for the alias file to have effect.

The output format is selected through the tabs arrayed below the Input Source buttons. Each tab, when selected, displays a page that may contain format-specific settings. These pages are very similar to corresponding pages in the Export Control panel, and the settings in the two panels track. The Format Conversion panel provides some additional choices and options, however. The differences are described below.

The output format is GDSII. When the Input Source is set to Layout File, this page contains an Input File Type menu. This menu contains two choices: archive and gds-text. The latter choice enables back-conversion to GDSII of the ASCII representation previously generated from a GDSII file using the ASCII Text output format tab. The archive menu choice should be selected when reading normal layout data.

The header of a GDSII file optionally contains information about fonts, reference libraries, and other things. This information is saved in a file named ``gds_header_props'' in the same directory as the output files, when converting to native files only. The file is subsequently ignored by Xic, as this information is not used by Xic.

The output format is OASIS.

The output format is CIF.

The output format is CGX.

When translating to CGX format, the multi-box capability of BOX records in CGX is not used. However, this feature is used when CGX files are written from memory. Thus, reading a hierarchy into Xic and writing out a CGX file will probably result in a smaller CGX file than using the direct conversion.

XIC Cell Files
The output will be written to a family of native-format cell files.

When the selected output format is Xic Cell Files, the input will be converted to a number of native cell files, one for each cell defined in the input. The same result can be obtained by reading the input file into the database with the Open command, and then using the Export Control panel to generate the Xic files.

The output will be converted to an ASCII text representation of the input file format, for GDSII, OASIS, and CGX input. This may be useful for debugging problematic layout files. The ASCII text format produced for GDSII can be back-converted to GDSII through use of the gds-text selection in the Input File Type menu of the GDSII page. The ASCII representation of OASIS files can be back-converted to OASIS with tools available from Anuvad. The two check boxes that appear on this page apply when translating OASIS:

OASIS text: print offsets
This sets/unsets the state of the OasPrintOffset variable, and when active the first token of each printed record contains the offset in the file or containing CBLOCK record. When not active, offsets are not printed.

OASIS text: no line wrap
This sets/unsets the state of the OasPrintNoWrap variable, suppressing line breaking when active. In this case, each record will use a single (possibly very long) line. When not set, lines are broken and indented.

Note that the Input Source choice will affect the availability of output format tabs, in particular if other than Layout File is selected, the available tabs are GDSII, OASIS, CIF, CGX.

Below the output format selection tabs, there are two tabs which alter the lower half of the panel. The Setup page provides some format-independent settings. The Convert File page provides the button to actually start the process.

next up previous contents index
Next: The Setup Page Up: The Format Conversion Button: Previous: The Format Conversion Button:   Contents   Index
Stephen R. Whiteley 2022-05-28