Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Load Template File Form

Name is the user defined name of the template file.

Filter allows you to specify a letter or keyword to filter the partition names.

Load sections loads the I/O Pins section of the template file.

Existing data either Merges or Replaces the template file.

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Placement Planning Form (Assisted CMOS)

Partition lets you select a partition that was created from the Partitioning form.

Select From Layout allows you to select a partition from the layout window.

Style lets you select and load one of the available styles.

Assisted CMOS lets you define rows with full flexibility for device or cell-level placement styles.

Style File is used if you do not find the style you want to load then you can load a user defined style.

Browse opens the Open File form.

Load loads the file specified in the Style File field.

Load Row Template For activates the buttons and fields for the template file.

Entire Design loads the template for the entire design.

Selected Partition loads the template for the partition that you have selected.

Template File is the template file created from theDesign – Save To Template command.

Browse opens the Open File form.

Load loads the specified template file.

Region are used as boundaries within which to apply the parameters specified in the form. Once the rows are created the regions no longer exist, but you can still manipulate the rows. You can draw rows outside the region.

Region Shape determines the shape of the region.

Rectangle creates a rectangular region.

Origin X sets the X coordinate of the lower left corner of the lowest numbered row (region) being edited.

Origin Y sets the Y coordinate of the lower left corner of the row (region).

Width lets you enter the width of the row you want (larger than the height if you want horizontal rows).

Height lets you enter the height of the row you want (larger than the width if you want vertical rows).

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Polygon creates a polygonal region.

Points field appears after selecting the polygon option. Type in the coordinates, or when using the Draw option the points are updated in the Points text field.

Draw lets you use the mouse to specify the corners of a rectangle in the layout cellview.

The rectangle sets the placement region and the X, Y, Width, and Height fields are filled in with the appropriate values.

Update updates the region.

Delete removes the drawn region.

Properties are for the pins.

Allow For Pins secures a space from the boundary edge equal to the size of the pin plus the spacing rule. This prevents rows from overlapping pins.

Allow Region To Expand allows you to not decide on the size of the region. Therefore rows can grow beyond the chose region if they need to. The direction of growth is determined by the user.

Horizontally draw stretch rows in a horizontal direction.

Vertically draw stretch rows in a vertical direction.

Allow Partition To Expand applies the same concept to the partition boundary. Rows would be able to offshoot beyond the partition boundary.

Row allows you to create rows.

Row Name allows you to type a name for your row(s). If you do not specify a row name, the default row name is assigned, starting with Row1, Row2, etc.

Direction is the default direction for rows, either Vertical or Horizontal.

Utilization:

Within Row is how much of a row should be used by the components vs. how much should be left for routing. Specify either 100% Utilization or Specify %.

Between Row is how much of the region should be occupied by rows vs. how much should be left for routing channels. Specify the option Provide Row Spacing or

Specify %.

Number of Rows allows you to specify Maximum or Specify by typing in the text

field the number of rows.

Rails allows you to specify information for power and ground pins.

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Power Rail

Layer allows you to specify the layout on which the rails are drawn.

Width allows you to specify the width of the supply rails.

Net Name allows you to specify the net to which the rows belong.

Ground Rail

Layer allows you to specify the layout on which the rails are drawn.

Width allows you to specify the width of the supply rails.

Net Name allows you to specify the net to which the rows belong.

Rail Pattern specifies how N and P devices alternate between rows or how cells alternate. The patterns that you can use are N-P-P-N, P-N-N-P, N-P, or P-N.

Position controls the relative position of rails with regard to rows. Specify either Inside,

Outside, or Center.

Row Spacing Within N-P Pair controls the distance between the N-P pair.

Minimum N-P Component specifies component spacing rule between N and P components.

Components

PMOS

Width Threshold is the maximum width allowed after MOS device folding is performed. The default value comes from the CDF data for the device. If the threshold value is 0, the value of the Fold Threshold option set in the Edit Component Types form is used.

Diffusion Spacing sets the minimum spacing required between adjacent MOS chains. This value affects the estimation of the number of rows required.

NMOS

Width Threshold is the maximum width allowed after MOS device folding is performed. The default value comes from the CDF data for the device.

Diffusion Spacing sets the minimum spacing required between adjacent MOS chains. This value affects the estimation of the number of rows required.

Align Components controls the relative alignment of devices in adjacent rows.

Inside aligns the P and N devices that are aligned toward each other.

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Outside alignment aligns the devices away from each other.

Center aligns the devices with the row center line.

Allow Chaining determines that components will be chained.

Stack Partition Parameter sets the device stacking partition parameters.

Max Chain Size sets the maximum number of devices in stack.

Layout Generation allows you to control whether components would have to be regenerated if necessary or only missing components would be added.

Regenerate All regenerates all components.

Generate Only Missing Components generates only missing components.

Preserve Constrained Objects is used with only the Regenerate All option. The constrained objects are not deleted.

Estimates creates the rows but does not generate any layout components.

Calculate Estimates gives you an estimation of the pmos and nmos devices within a row.

Update Layout updates the current layout with the assumption that you do not want to change any of the parameters.