Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Information About Forms

■Auto Placer Form

■Partitioning Form

■Choose Component Types Form

■Pin Placement Form

■Load Template File Form

■Placement Planning Form (Assisted CMOS)

■Placement Planning Form (Assisted Standard Cell)

■Placement Planning Form (Assisted Mixed CMOS/Standard-Cell)

■Placement Planning Form (Manual User-Defined)

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Auto Placer Form

Group CMOS Pairs is used with CMOS designs that have been generated with chaining.

This option does not work with devices that have been manually abutted because clustering needs chaining information.

Group M factor Devices automatically adds a grouping constraint for complimentary MOS devices that have a M (multiplication) factor from the schematic.

Place Selected Objects Only places only the objects in the selected set. If this option is not selected, all objects in the cellview are placed.

Allow Rotation rotates the components as a part of optimization. If this option is turned off, the components are moved, not rotated.

ECO Mode places any components you had left unplaced outside the design boundary but does not touch the placement of components that are already placed inside the design boundary.

Global Placement places components without regard to their initial placement. Overlap violations between components might be ignored. The placer optimizes global objectives such as total wire length. Typically, you would select this option the first time you place a design or to discard previous unsatisfactory placement results.

Optimize Placement performs a detailed placement. This option lets the placer run until the objective cost is achieved.

Runtime controls how long the optimizer tries to optimize to achieve the best possible placement. Choices are quick, moderate, and optimized.

Run Spacer within Rows adds/subtracts space within each row.

Run Spacer between Rows adds/subtracts space between each row.

Reserve Space For Routing (%) lets you indicate the percentage of extra space you want added, above what the routing channels between rows should occupy, to improve routability. Use this option with the Run Spacer between Rows.

Insert Filler Cells fills the spaces where there are no components in the rows with the filler cells you defined in the Component Types form.

Insert Substrate Contacts inserts substrate contacts in the rows based on a pre-specified minimum and maximum contact spacing value. This option is only available with the standard/ mixed cell placement.

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Save As lets you specify a new library, cell, and view name for the placed cellview. By default, this option is disabled. If you do not select this option, the current and placed names are the same and these fields are grayed out.

Important

Be sure to save the placed (output) cellview to disk before translation if you want to preserve any edits that are still in memory.

Edits to the output cellview are not saved to disk automatically before placement. To discard the changes the placer makes, do not save the output cellview. However, this also discards any edits in memory.

■When you let the placer update the source layout cellview.

■When you specify a different cell or view name, but that cellview happens to be open and modified in another window.

Library sets the new library for the placed cellview.

Cell sets the new cell name for the placed cellview.

View sets the new view name for the placed cellview.

Browse displays a library browser to let you choose the new name.

Open Window displays the placed view in a new window after placement, if it is not already displayed. Otherwise, the system updates the output view in an existing window.

Rules File lets you type the name of a rules file.

Set File opens the Open File window, which displays the files on your system so that you can choose a rules file.

Job Host

Local runs the placer on the local host which is the default setting.

LBS submits the placement job to the LBS (Load Balancing Service) which schedules the placement job according to your settings and the availability of computing resources. The final placement session will run on the selected host using the dfII working directory for data read/write.

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Partitioning Form

Select allows you to set up the partitioning environment.

Component allows you to select a component in the layout window and have the component name be highlighted in the Partitioning form.

Partition allows you to select a partition in the layout window and have the partition name be highlighted in the Partitioning form. This option must be turned on when you are attaching a shape on a soft fence to an existing partition.

Note: You must click on the Link button and then click inside the layout window to have the selected component/partition be highlighted in the Partitioning form.

Link links the Partitioning form to the cellview in the context of partitioning. For example, the

Link option allows you to select components or partitions in order to highlight them in the Partitioning form.

Choose or type a Partition name adds the name of a new partition or allows you to choose from a list of existing partition names. If the Partitioning form is linked and any shape is already attached to the partition, the partition is highlighted in the layout window.

Create Partition adds a new partition from the Choose or type a partition name in the text field.

Delete Partition deletes the partition. If there are any components assigned to this partition, they are assigned to the boundary by default.

Attach Shape attaches a shape to the current partition. The shape must be only on the softFence layer. The shape must already exist in the layout. If this shape is already assigned to another existing partition, then the shape is detached from the previous partition and attached to the current partition.

Detach Shape detaches the selected shape from the current partition.

Template allows you to specify a template file name. Typing a name in the text field enables the load button and the template file is loaded to the form.

Browse allows you to browse/specify a template file name using the Open File form.

Load loads the partition information from the template file specified in the Template text field in to the Partitioning form.

Display by defines what will be displayed in the component browser.

Flat Instances displays instances that have no hierarchy.

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Hierarchical Instances displays instances at the top level of the hierarchy.

Note: If your design is hierarchically flat, then the display will appear the same for both

Flat and Hierarchical Instances option. This is because the Hierarchical Instances option displays top level instances and Flat Instances displays leaf instances. Top level and leaf instances in a flat design are the same.

Component Types displays the component types used with the instances.

Source master displays the names of all the master symbols existing in the layout.

Target master displays the names of all the master layouts existing in the layout.

All displays all partitions and their components.

Boundary displays components that are placed in the boundary.

Partition displays the components belonging to a specific partition.

Sort by sorts information by component (Name) or Partition. When sorting partitions, all partitions are first sorted, then components in each partition. You can click on either the

Component Name or Partition Name cyclic field to sort.

Select type in a search patter to select the corresponding components in the component browser.

Filter allows you to filter components from what is already selected in the component browser.

Reset set allows you to clear the highlighted set.

Add to set allows you to add to a new selected set to an already existing set. For example the existing highlighted set is aX aY aZ aP aQ. You select b* in the component browser, then select Add to set and click OK. The new highlighted set is all of the components including a* and b*.

Remove from set allows you to remove any other selected elements from the preselected set. For example if you type in the Select fieldap and then click Ok the new highlighted set is aX aY aZ aQ.

Limit to set allows you to highlight a subset of components from the highlighted set. For example if you type in the Select fieldaY and click OK the new highlighted set is aY.

OK invokes the action based on correct Filter options.

Component and Partition Browser displays components and their current partitions.

Target Partition is the name of the partition that you want components to be assigned to.

Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Move assigns the selected instances from the component browser to the current partition.