Soft Block Mode

Soft Block mode lets you define the soft blocks that will be created by the Floorplan – Generate Physical Hierarchy or the Generate Abstract From Symbol commands. You select the instances to be included and define boundary, pin, and blockage parameters for the block you want to create. You can also remove the parameters from an existing soft block to prevent it being created when the physical hierarchy is generated.

Generate Physical Hierarchy (GPH) is the equivalent of a hierarchical Generate All From Source command. It generates instances from source at different levels of hierarchy, including soft blocks that are defined with type LAYOUT.

In order for the bus terminal and bus bit order (ascending or descending) information to be transferred from the schematic to the layout, you need to set the environment variable, createImplicitBusTerminals, before running GPH. This creates implicit bus terminals and bus order information in the layout view, derived from the bus terminals and bit order information in the schematic cellview. In addition, this avoids the need to run verilogAnnotate before referencing the layout cellview when:

• • Running verilog2oa
  • When importing another verilog design into Innovus

See createImplicitBusTerminals.

Further, for the implicit bus information to be carried to the abstract, the abstract must be generated with the bus annotation option enabled. This can be achieved by setting the AnnotateBusInAbstract option to “True” in the Abstract Options file.

See Bus Annotation in Abstract Generator.

Unlike the GPH command, Generate Abstract From Symbol command generates soft blocks that are defined with type ABSTRACT.

Use Configure Physical Hierarchy in Soft Block mode to define soft blocks before initial generation or if you need to make more radical changes (by, for example, generating new soft blocks or flattening others that you no longer require). If you want to make changes to existing soft blocks that do not require the physical hierarchy to be regenerated, use the Edit Soft Blocks command instead. See Soft Block Editing.

You define a soft block by selecting a component in the soft block Instances table and specifying the following in the Attributes pane.

• The type of soft block that will be created.
• The height, width, area, or shape of the place and route boundary.
• The length, width, layer purpose, and signal type of soft pins.
• Routing and placement obstructions inside the block.

Alternatively, you can load soft block parameters directly from another layout cellview using the Initialize Soft Block Parameters Using Physical View command.

You also need to define parameters for the top-level instance so that the Generate Physical Hierarchy command has the information it requires to generate the boundary and pins. The top level instance has type LAYOUT, which cannot be changed.

Related Topics

Setting the Cell Type

Defining Soft Block Parameters

Specifying the Boundary

Specifying I/O Pins

Specifying LayerHalo Obstructions

Specifying Cover Obstructions

Loading Soft Block Parameters from Another Cellview

Saving and Loading Soft Block Parameters to a Floorplan File

Generating the Physical Hierarchy

Creating a Physical Binding

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