This technology file keyword is used to import Cadence Virtuoso ascii technology and display resource (DRF) files into Xic. The syntax is
ReadCds filename
This can appear anywhere in the technology file, and will cause Xic to read information from the Cadence startup file given in filename. This should be a full path to the file, unless the file is in the library search path.
Presently, there are two types of Cadence startup files that are understood: the Display Resource File, and the ASCII Technology File. Although the names may vary, the display resource file in one installation is named ``display.drf'' and the technology file is named ``techfile.txt''. It is also possible that the data are combined into a single file. In this case, the display resource information should come first.
The display resource file must be read first, i.e., there should be two calls to ReadCds, first with the display resource file, then for the technology file. A minimalist Xic technology file can consist of these two statements only, or just one statement if the files are combined. This will set the layers and their colors, fill patterns, and some of the electrical information.
When a technology file is written with the Save Tech command, it will have the usual format and the ReadCds lines are not included in the new file.
The files are collections of ``nodes'', as understood by the Lisp parser (see 16.18.3). A named node has the form
name( data ... )The data are other Lisp nodes, strings, or numerical data or expressions. This can occupy arbitrarily many lines in the file. There can be no space between the node name and the opening parenthesis.
The files consist of one or more successive Lisp nodes, with names that are defined by Cadence. A node which consists of a list of nodes is termed a ``class''. Most of the top-level nodes which appear in the ASCII technology file are actually classes. The nodes that are defined by Cadence for these two files, and are understood by Xic are described in the sections below.