Placement Mode

This section lets you specify the placement mode of schematic instances and components.

As In Schematic

Generates the selected schematic instances and pins together in the layout view. By default, the components are placed in the same relative positions as in the schematic. However, you can change the alignment, spacing, and orientation of the components by using the options in the form. You can chain and fold mfactored components, both generated and partially generated.

You cannot change the instance properties or pin attributes in this mode.

Array

Generates the selected components as ungrouped objects, a Modgen, a mosaic, or a group array. Irrespective of their type, the arrays that you generate are XL-compliant. By default, the row-column spacing is DRC correct, but you can choose to modify the row, column, or spacing values for an array, as appropriate. For Modgens, mosaic,and group arrays, you can modify these values even after the array is generated. But, for instance arrays, if the row, column, or spacing values are modified, the array must be regenerated.

Array placement mode cannot be used to place pins.

Environment variable: generateModgens

Individually

Generates each of the selected schematic components one at a time in the layout view. When generating instances, the form shows the name and master of the instance currently being generated; when generating pins, the form shows the name of the pin currently being generated and lets you change the attributes of that pin.

The Chain option is not available in Individually mode. To chain multiple devices, select the Chain option in As In Schematic mode or use the Generate Chained Devices command.

Chaining and Folding

This section lets you specify the options for chaining and folding of transistors.

Fold

Automatically divides MOS transistors into folds to optimize utilization.

If the disableFolding environment variable is set and the folding threshold for the component type is set to 0, folding is disabled.

Environment variables: initDoFolding, disableFolding

Chain Folds

Automatically chains the individual folds of a transistor. For the Chain Folds option to be available, only the Fold check box must be selected. If you select the Chain check box as well, Chain Folds is disabled.

NMOS Fold Threshold

Specifies the maximum size of the folded NMOS transistor. This value defaults to the folding threshold value set on the connectivity source component. Changing this value overrides any folding threshold value defined in the component type.

PMOS Fold Threshold

Specifies the maximum size of the folded PMOS transistor. This value defaults to the folding threshold value set on the connectivity source component. Changing this value overrides any folding threshold value defined in the component type.

The NMOS Fold Threshold and the PMOS Fold Threshold options are available only when the Fold check box is selected. The NMOS Fold Threshold and the PMOS Fold Threshold fields are disabled if the fold threshold value for all the component types is set to 0 and the disableFolding environment variable is set.

Folding is prevented and a warning issued if the disableFolding environment variable is set and the component type fold threshold value is set to 0, but the fold threshold value on the form is > 0.

Chain

Automatically abuts the selected set of MOS transistors to form a chain.

The Chain option is available only for instances in As In Schematic mode. The transistors to be abutted must be set up for abutment first.

Interdigitate Chains

Automatically identifies nodes that qualify as pseudoparallel connections and defines them during chaining and abutment. A pseudoparallel net connects nodes that are always at the same voltage, so that current does not pass through the net.

This option does not control the automatic identification and creation of pseudoparallel nets during manual abutment. To do that, select Create pseudoparallel connections on Generation tab of the Connectivity form.

Environment variable: lxAllowPseudoParallelNets

Alignment

This section lets you change the alignment and spacing between the selected components before you place them in the layout view.

See Aligning Objects by using the Align Toolbar.

Align Left

Aligns the left edges of the selected components.

Align Vertical

Aligns the vertical center lines of the selected components.

Align Right

Aligns the right edges of the selected components.

Align Top

Aligns the top edges of the selected objects.

Align Horizontal

Aligns the horizontal center lines of the selected objects.

Align Bottom

Aligns the bottom edges of the selected objects.

Align Spacing

Spaces the components evenly, separated by the distance specified in the text field. If you switch off this option, the components are aligned but retain their original spacing.

Orthogonal Spacing

Additionally spaces the components perpendicular to the align direction, with each successive component offset by the distance specified in the text field.

Design Planning

This group box is available only when you have the Layout EXL or higher license checked out.

Virtual Hierarchy

Lets you generate a virtual hierarchy for the selected schematic instance, which can be accessed using the DESIGN PLANNING category in the Navigator assistant. By default, the option is OFF.

When set to nil, the selected schematic instance is generated as a regular layout instance.

Unplaced

Opens the Instance/Pin List, which lists each component in the schematic for which there is no corresponding instance or pin in the layout.

When you select a device from the list, the form displays properties set for that device.

When you select a pin, the form shows the options described in Generate Selected Components - Pin Options Form.

Orientation buttons

This section lets you change the orientation of the selected instance.

Rotate

Rotates the component 90 degrees counterclockwise.

Sideways

Mirrors the component on the y axis (flips it horizontally).

Upside Down

Mirrors the component on the x axis (flips it vertically).