Stats

  • Locked Locked
  • Replies 1
  • Subscribers 144
  • Views 13654
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Constraint info

psill000

I am trying to get info on constraints for schematics/layout.

I started reading the cadence pdf files on constraints.

What key sections or functions should I read?

What are the capabilitdies of constraints?

Areas of interest for macros currentlyK

  • pin layer and placement
  • define wire tracks nets, widths and spacing
  • instance placement ( standard cells )

If there are other areas I should investigate, please let me know.

Paul

  • Hi Paul

    Usage of constraints is quite simple. We just need to know the following key points:
    - There are 3 classes of constraints (electrical, placement and routing). You are most probably more concerned with placement and routing constraints
    - wire widths, spacing, etc can be defined using "Process Rule Overrides" constraints
    - Placement of instances can be controlled using distance, alignment, orientation, etc constraints
    - "Constraint manager" assistant can be used to add the constraints
    - Constraints can be added in schematic (or layout) and propagated to layout (or schematic)
    - "Circuit prospector" assistant can be used to quickly identify different devices, circuit modules (e.g. current mirror) so that constraints can be added to them

    You can try the following RAK (Rapid Adoption Kit) to have a better idea of creating and using constraints:

    IC 6.1.6 Constraint Driven Custom Design(22 Nov 2016)  
    "The constraint-driven flow enables you to capture and transfer design requirements formally through the Constraint Management System, and then use automatic and interactive tools to enforce the requirements in the layout to ensure convergence on design goals. Constraints can be verified between front and back to ensure that the layout is using them as intended and that they have been implemented correctly. Finally, the system also enables storing and reusing of constraints across designs or projects. Last Tested Release: IC 6.1.6.500.12 (ISR12)"


    Best regards
    Quek

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.