Stats

  • Locked Locked
  • Replies 4
  • Subscribers 125
  • Views 2582
  • 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

How to Find the drawn net("MET1" "drawing") in the layout.

ShrikantTI
Requirement is that I need to find if there are any existing nets or paths in the layout so that I can connect the rest except those paths. Another issue is that when i draw the path the skill command does not recognize it as net until there net expression is given unlike in schematic it takes a predefined value. I tried to explore using shapes but did not have much definitive solution. Please can you help? Also how to find which all terminals is the path or net connected? I need to get the name of the terminals from the subblock as the terminals of the subblocks are not visible. Thanks, Shrikant
  • Andrew Beckett

    Shrikant,

    Your question is rather unclear and hard to understand. Please read the Forum Guidelines and see if you can formulate your question more clearly.

    I don't really understand from what you've written what you actually have tried and what you are are trying to achieve.

    Kind Regards,

    Andrew.

  • skillUser

     Hi Shrikant,

    I agree with Andrew that your questions are not clear, however I will try to provide some information that may help you.

    If you are designing in Virtuoso Layout Suite L (VLS-L, or perhaps you are using the older version of the tools, in which case it is named Virtuoso Layout Editor, or VLE) then connectivity is not automatically added to shapes, except perhaps for pins (terminals).  Any shape can be checked for connectivity, look for a "net" attribute on the shape, if it is 'nil' then there is no connectivity for that shape.  For example, let's assume that I selected a path (or pathSeg) in the layout, then I could check connectivity using SKILL:

    
  car(geGetSelectedSet())~>net
  => db:0x1652d512

     If you are looking for connectivity awareness in the tool then your best bet is to use the XL level of the product (VLS-XL in IC61x naming, or the older VXL if using IC5141).  When you use VLS-XL you can start from a connectivity reference like a schematic and generate the layout devices and their connectivity very easily - then when you hook up these devices the tool can aid you in highlighting connected pins on devices, and various other productivity enhancing features.  In either L or XL tiers you can add connectivity to a shape like a path by selecting it, pressing 'q' or Edit->Basic->Properties to open a form that allows you to modify the Connectivity.  In VXL or VLS-XL you can show/hide incomplete nets, so you can easily spot if any connection is missing.

    Hopefully this will help you. As Andrew said though, a more precise question (with information like version number, it's important, which is why we ask for it!) will likely yield a more helpful response.

    Regards,

    Lawrence.

  • ShrikantTI
    Hi Andrew and Lawrence, I have been working on it let me post again once I come with more detailed flow. As now can you tell me what is the significance of the net without figs. When I create path and define connectivity it list in cvid~>nets but suppose I delete the previous path still the cvid~>nets shows this net name but with no figure. What does this mean? The net name exist only virtually will not affect. is there any way to remove them? Also when I create shape(ie path), does it mean that until I define connectivity it will not be considered as net? Thanks, Shrikant
  • Andrew Beckett

    The database can be used to represent logical connectivity either separate from or together with physical geometries. That way you can represent in the database how terminals of devices should be connected despite the fact that the physical routing has not been implemented yet. As you do the physical routing you can associate the geometries with the nets - and then the shapes are marked as being associated with the net. You can show (in the layout editor) flight lines for nets to show the logical connectivity if you wish (this is on the Display Options form) to show lines between pins on instances and also top level pins - assuming that the device has instTerm objects created too to associate the instance terminals with specific nets. Layout XL does this when it creates devices - the connectivity is set up in the database.

    Nets (like most database objects) can be deleted with dbDeleteObject().

    Regards,

    Andrew.

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.