What's Good About DEHDL-CM Physical and Spacing Constraints? You'll need SPB16.2 to see!

That's right - the SPB16.2 release now includes support for Physical and Spacing (P&S) Constraints from within the Design Entry HDL Constraint Manager.

Prior to this release, you could only set electrical constraints in Design Entry HDL Constraint Manager (CM). Beginning with the SPB16.2 release, in addition to electrical constraints, you can use Constraint Manager connected to Design Entry HDL to create, view, edit, and assign physical and spacing (P&S) constraints to a net or group of nets. You also have the option to switch between read-only and edit modes for P&S constraints.

Physical and spacing constraints impact the physical layout of a PCB board or of a SiP, and are therefore usually captured and modified during the layout design stage by the layout engineer. However, stack-up information and some physical and spacing constraints are usually finalized during the design capture stage itself. For example, physical constraints, such as minimum line width and maximum line width, which have an impact on the manufacturing as well as the functioning of the design, are available. Such constraints can be entered during the design stage, and later on modified in physical layout. Similarly, information such as layers to be used by signal groups, and also trace proximity - these are often decided at an early stage of the development. In the SPB16.2 release, the layer stackup and P&S constraints can be imported via a technology file into the front-end Constraint Manager, or fed back from the board via Import Physical.

So now in the SPB16.2 release, the following operations are possible in DEHDL Constraint Manager:

• Ability to enter, view and/or modify Physical and Spacing constraints
  
• Ability to apply Constraint Sets on the objects of Physical and Spacing worksheets
  
• Ability to override (directly set) values to constraint objects, aligning with the back-end
  
• Ability to apply Physical & Spacing Constraints at all hierarchy levels
  • Note: It is recommended that the layer stackup of lower-level blocks is the same as the layer stackup for the root design. The layer stackup defined at the top level is the winning stackup, and if none is found at the top level, the stackup coming from lower level blocks is ignored.
    
• Ability to modify Physical and Spacing Constraint Sets defined in the back-end
  
• Technology file import/export. (note layer stackup can be defined in the back-end only, but it can be viewed in the front-end)

Because of potential issues in a mixed release environment (e.g. a 16.2 Front End with a 16.01 Back End), be advised that  the Constraint Manager Enabled flow requires the same release across the Front-End/Back-End flow.

Also note that any front-end design that utilizes the CM-enabled flow and which has been migrated to 16.2 is not backwards compatible with 16.01 or earlier releases.

As always, I look forward to any suggestions or questions you may have on this topic.

Jerry "GenPart" Grzenia