next up previous contents index
Next: Inductance/Resistance Extraction Interface Up: Xic Variables Previous: Extraction Menu Commands   Contents   Index


Capacitance Extraction Interface

The following variables apply to the capacitance extraction interface described in 16.17.1. Most of these are associated with entry fields in the Cap Extraction panel (see16.17.2), which is brought up with the Extract C button in the Extract Menu.

FcArgs
Value: string.
This variable can be set to a string, which will be included in the argument list when capacitance extraction is initiated through the interface, with the Run Extraction button in the Run page of the Cap Extraction panel, or through the !fc command. The variable tracks the FcArgs text entry area in the Run page of the Cap Extraction panel, from where the variable is most conveniently set or edited.

If the interface detects that FasterCap from FastFieldSolvers.com is being used, and this entry is empty, the default argument string

-b -a0.01
will be imposed. A ``-b'' option will always be added if missing from the FasterCap arguments list, as this argument is necessary for correct FasterFap operation in this mode. The ``-a'' option is almost always used, as it specifies auto-refinement, however it is technically not necessary and won't be imposed if not given, except in the case where no arguments are given at all.

FcForeg
Value: boolean.
If this variable is set, then the Run Extraction button in the Cap Extraction panel Run page will initiate a process running in the foreground. If not set, jobs are run in the background, so that the user can continue using Xic while the run is in progress.

It is not clear why there would be any reason to run in the foreground, except possibly for debugging.

This variable controls, and is controlled by, the setting of the Run in foreground check box in the Run page of the Cap Extraction panel from the Extract Menu.

FcLayerName
Value: string.
The capacitance extraction interface uses a special layer for masking of objects to be included in the capacitance extraction run. By default, this layer is named ``FCAP''. If any shapes exist on this layer in the current cell hierarchy, all objects will be clipped by these shapes before capacitance extraction. If no shapes are found on this layer, then all objects in the current cell hierarchy will be included in capacitance extraction.

If this variable is set to the name of an existing layer name in the layer table, that layer will do the clipping.

FcMonitor
Value: boolean.
If this variable is set, then the standard output from the running capacitance extraction program is printed in the console, in addition to being saved in a file. The console is the shell window from which Xic was started. This allows the user to monitor the run, and abort if something isn't correct.

This will also apply if the program is being run in the foreground, however operation is a bit different. In this case, a ``| tee'' is added to the command string ahead of the output file name. There are two implications: the text will be block buffered, and therefor won't appear in the window immediately, and in Windows, there is no native tee command so that the operation may fail. However, a tee command is provided with the Cygwin tools, and there are other sources. In the normal case of running in the background, output will again be block buffered under Windows, but there is no requirement for a tee command.

This variable mirrors the state of the Out to console check box in the Run page of the Cap Extraction panel from the Extract Menu.

!! 071814

FcPanelTarget
Value: real number 1e3 - 1e6.
When not using a capacitance extraction program that provides automatic refinement, such as FasterCap from FastFieldSolvers.com, this provides a crude panel refinement capability. This variable provides a number, and the interface will attempt to split all panels into equal area pieces, where the total number of pieces is the number given. The refined panels are output into the list file, which consequently can grow large.

When not set, no such refinement is done. It should not be set for normal use of FasterCap, but is needed if using the Whiteley Research version of FastCap or similar.

!! 071814

FcPath
Value: directory path string.
This variable can be set to a full path to the capacitance extraction program executable.

If this is not set, Xic will attempt to use ``/usr/local/bin/fastcap'' as the FastCap program (or ``/usr/local/bin/fastcap.exe'' in Windows). If this executable does not exist, Xic will attempt to find ``fastcap'' (or ``fastcap.exe'' in Windows) in the shell search path when running in the foreground, and background runs will fail.

This tracks the setting of the text entry field in the Run page of the Cap Extraction panel.

FcPlaneBloat
Value: real number 0.0 - 100.0.
If set to a positive value, the substrate is modeled to extend horizontally outward by this value beyond the bounding box of the extracted geometry. See the discussion in the interface description in 16.17.1 for more information. If not set, no dimensional change is assumed.

FcUnits
Value: units string.
This variable can be used to specify the length units used in generated capacitance extraction input files. The variable can be set to a string consisting of one or the abbreviations ``m'' (meters), ``cm'' (centimeters), ``mm'' (millimeters), ``um''" (microns), ``in'' (inches), and ``mils''. The long form word will also be accepted. This variable is most conveniently manipulated with the choice menu found in the Cap Extraction panel Params page.


next up previous contents index
Next: Inductance/Resistance Extraction Interface Up: Xic Variables Previous: Extraction Menu Commands   Contents   Index
Stephen R. Whiteley 2017-04-09