next up previous contents index
Next: FastCap/FastHenry Interface Up: Xic Variables Previous: Convert Menu   Contents   Index


Extraction Menu Commands

The !set keywords below affect the commands found in the Extract Menu.

EraseBehindTerms
Value: boolean or ``all''.
If set, the area inside the bounding box of terminals made visible by the Show Terminals command is erased, to promote visibility of the text. If set to ``all'', all terminals are erased behind, otherwise only the cell's formal terminals are erased behind.

TermTextSize
Value: integer 6-48.
This variable can be used to set the height, in pixels, of the text used in rendering terminals and cell labels in electrical mode. If not set, the default is 14.

TermMarkSize
Value: integer 6-48.
This variable can be used to reset the pixel size of the cross used as a terminal mark. If not set, the default is 20.

LayerSearchUp
Value: boolean.
When set, the layers are searched from bottom to top in the extraction functions. Otherwise, layers are searched from top to bottom. This affects the association of terminals to layers, and the layer selected in the Show Paths and Quick Paths commands in the Extract Menu.

ExtractOpaque
Value: boolean.
When set, Xic will ignore the OPAQUE flag and perform extraction normally on cells with this flag set. The OPAQUE flag would otherwise suppress extraction on the contents of the cell. This flag is set in the Flags property of physical cells.

FlattenPrefix
Value: string.
In extraction, physical subcells whose name begins with the string value of this variable are flattened into the parent cell for extraction purposes.

Note: in releases of Xic prior to 2.5.19, this variable was named ``PnetFlattenPrefix''.

GroundPlaneGlobal
Value: boolean.
When set, every object in every cell on a clear-field ground plane layer is assigned to group 0. If not set, only the largest area group on this layer, in the top-level cell, is assigned to group 0.

GroundPlaneMulti
Value: boolean.
When set, a layer specified as GroundPlaneClear in the technology file will be inverted, and the inverted version used for grouping and extraction. The MultiNet keyword which optionally follows GroundPlaneClear in the technology file effectively sets this variable. If this variable is unset, then no inversion takes place, and the absence of the GroundPlaneClear layer is taken to indicate ground (group 0). This variable has no effect unless a GroundPlaneClear layer exists.
Note: This replaces the HandleTermDefault variable which existed in earlier Xic releases.

GroundPlaneMethod
Value: integer 0-2.
This sets the method used to invert the ground plane for grouping and extraction, if the MultiNet keyword has been applied to a GroundPlaneClear layer in the technology file. The possible values are integers 0-2, which have the same meaning as the integer that optionally follows MultiNet in the technology file (see 11.1.1).

NoMergeParallel
Value: boolean.
Setting this variable suppresses merging of parallel-connected devices during extraction. This applies to all devices, and supersedes the Merge directive in the device blocks or the technology file.

NoMergeSeries
Value: boolean.
Setting this variable suppresses merging of series-connected devices during extraction. This applies to all devices, and supersedes the Merge directive in the device blocks of the technology file.

NoMeasure
Value: boolean.
This turns off the extraction of parametric data for devices in the extraction system. This is mainly for debugging, but may save time if the user is interested in topology only. The measurements can be time consuming.

QpathGroundPlane
Value: integer 0-2.
This variable controls how the Quick Paths command uses the inverted ground plane. An inverted ground plane is created while grouping under extraction, if enabled. The choices are

0 Use the inverted ground plane if available
1 Create the inverted ground plane if necessary, and use it
2 Never use the inverted ground plane

The default behavior is to use the inverted ground plane if it already exists, as for ``0'', if this variable is unset.

NoEnet
Value: boolean.
If set, the netlist is skipped when writing output in the Dump Elec Netlist command. This variable corresponds to the net check box available in that command, with inverse logic.

EnetSpice
Value: boolean.
If set, SPICE output is included in the file produced from the Dump Elec Netlist command. This variable corresponds to the spice check box available in that command.

EnetBottomUp
Value: boolean.
When set, the electrical netlist file (produced by the Dump Elec Netlist command) order will be leaf-to-root, i.e., subcells will be listed first. If not set, the reverse order is used.

NoPnet
Value: boolean.
If set, the extracted netlist listing is skipped in output from the Dump Phys Netlist command. This variable corresponds to the net check box available in that command, with inverse logic.

NoPnetDevs
Value: boolean.
If set, the extracted device listing is skipped in output from the Dump Phys Netlist command. This variable corresponds to the devs check box available in that command, with inverse logic.

NoPnetSpice
Value: boolean.
If set, the SPICE listing of extracted devices is skipped in output from the Dump Phys Netlist command. This variable corresponds to the spice check box available in that command, with inverse logic.

PnetBottomUp
Value: boolean.
When set, the physical netlist file (produced by the Dump Phys Netlist command) order will be leaf-to-root, i.e., subcells will be listed first. If not set, the reverse order is used.

PnetShowGeometry
Value: boolean.
If set, the net field (if activated) in the file produced from the Dump Phys Netlist command will include a listing of the objects that comprise the wire net. The listing is in modified CIF syntax where 1000 units per micron is used. This variable corresponds to the show geometry check box available in that command.

PnetIncludeWireCap
Value: boolean.
If set, the spice field (if activated) in the file produced from the Dump Phys Netlist command will include capacitors representing the computed wire net capacitance to ground. The Routing layers must have the Capacitance keyword applied in the technology file. The added capacitors have a special prefix ``C@NET'' which allows them to be subsequently recognized as wire net capacitors by Xic. This variable corresponds to the include wire cap check box available in that command.

PnetListAll
Value: boolean.
In files produced with the Dump Phys Netlist command, references to subcells that are flattened or wire-only are normally not listed. If this variable is set, these cells are included in the listing, which may be useful for debugging. This variable corresponds to the include all devs check box available in that command.

SourceAllDevs
Value: boolean.
In the Source SPICE command, ordinarily only devices which have fixed (user-specified) device names will have properties updated. This is to avoid errors, since the internally generated names can change, and may not match those in the SPICE file. If this variable is set, the default action is to update all devices. This variable corresponds to the all devs check box available in that command. The variable is also used by the !source command.

SourceCreate
Value: boolean.
In the Source SPICE command, if this variable is set, the default action is to create missing devices. Otherwise, device parameters may be updated, but no new devices are created. This variable corresponds to the create check box available in that command. The variable is also used by the !source command.

SourceClear
Value: boolean.
In the Source SPICE command, if this variable is set the default action is to discard the existing contents of the electrical part of the cell before updating. This variable corresponds to the clear check box available in that command. The variable is also used by the !source command.

NoExsetAllDevs
Value: boolean.
In the Source Physical command, if this variable is set, only devices that have a permanent (user-supplied) name will be updated. If not set, all devices will be updated. This variable corresponds to the all devs check box available in that command, with inverse logic. The variable is also used by the !exset command.

NoExsetCreate
Value: boolean.
The default behavior of the Source Physical command is to create missing devices. Setting this variable will change the default action to no device creation. This variable corresponds to the create check box available in that command, with inverse logic. The variable is also used in the !exset command.

ExsetClear
Value: boolean.
When set, the electrical cells are cleared before updating with the Source Physical command. This implies create, i.e., new devices will be created since the cell is empty. This variable corresponds to the clear check box available in that command. The variable is also used in the !exset command.

ExsetIncludeWireCap
Value: boolean.
When set, computed routing capacitors will be updated or created in the electrical database when using the Source Physical command. These capacitors have a name prefix of ``C@NET''. This variable corresponds to the include wire cap check box available in that command. The variable is also used in the !exset command.

NoPermute
Value: boolean.
When this variable is set, the association algorithm will not attempt to iterate through the combinations when searching for a solution. Many circuits do not require a permutation search, however some circuits, and in particular circuits where the wiring is incomplete, may require a lot of time for the permutation search. Of course, if a permutation search is needed and not performed, LVS will fail. This variable is mostly for debugging, or for cases where association is not needed.

Permutes are also skipped if a device or subcircuit is found that can not possibly be associated.

RLSolverDelta
Value: floating point > = 0.01.
It this value is set, the resistance/inductance extractor will assume this grid spacing, in microns. The number of grid cells enclosed in the device will increase for physically larger devices, so that larger devices will take longer to extract. If this variable is set, the other RLSolver variables are ignored. Setting this variable may be appropriate if all resistors are ``small'' and dimensions conform to a layout grid.

RLSolverTryTile
Value: boolean.
If set, the extractor will attempt to use a grid that will fall on every edge of the device body and contacts. The device and contact areas must be Manhattan for this to work. If such a grid can be found, and the number of grid cells is a reasonable number, this will give the most accurate result.

RLSolverGridPoints
Value: integer 10-100000.
When not tiling (RLSolverTryTile is not set), this sets the number of grid points used for resistance/inductance extraction. This number will be the same for all device structures, so that computation time per device is nearly constant. Higher numbers give better accuracy but take longer. The value used if not set is 1000.

RLSolverMaxPoints
Value: integer 1000-100000.
When tiling (RLSolverTryTile is set), the maximum number of grid cells is limited to this value. If the tile is too small, it will be increased in size to keep the count below this value, in which case the tiling will not have succeeded so there may be a small loss of accuracy. Using a large number of grid points can take a long time. The value used if not set is 50,000.


next up previous contents index
Next: FastCap/FastHenry Interface Up: Xic Variables Previous: Convert Menu   Contents   Index
Stephen R. Whiteley 2006-10-23