Stats

  • Locked Locked
  • Replies 4
  • Subscribers 125
  • Views 4042
  • 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

LEF generation from abstract is missing class,symmetry, origin information

anandmohan

HI ,

I am trying to generate LEF file of an abstract (top level cell: TOP_CELL). Eventhough LEF is getting generated it is missing the following information.

###################################################
CLASS;
Symmetry ;
SIZE X Y;
FOREIGN TOP_CELL_NAME (0 0) N

ORIGIN (0 0);

#######################################


I am using LEF Version: 5.7
Virtuoso: IC6.1.7-64b.500.7

options  enabled in LEF generation menu window are

1) LEF File Name:  TOP_CELL.lef

2)cells

3)Output cell(s): TOP_CELL

4)Output views : abstract

5) Lef version: 5.7
6)No Technology

7)Generate cell list by: Cells in Design

8)Use GUI Fields


Is there anything wrong in the way LEF is being generated ?.  I am seeing the pin information and blockage layer information  available in the LEF file that was generated.



Regards
Anand

  • Andrew Beckett
    Seems odd. How was the abstract view created?
  • anandmohan
    HI Andrew,

    Abstract view was manually created by copying the pins from layout and placing it in a new view. Apart from pins abstract view had PR boundary and metal blockage layers (created as objects). The pins & layers are placed in same location as in layout.


    Regards
    Anand
  • Andrew Beckett

    Probably the simplest would be to use the abstract generator to build the abstract, but I suspect it's just that you're missing some cellView attributes and a prBoundary object.

    First edit the cellView properties (File->Properties) and fill in the CellType (I suspect yours is "none") - this sets the CLASS, and the Symmetry Type (this sets Symmetry in the LEF):

    Then you need a prBoundary object (not a shape on the prBoundary/drawing layer, but an actual object, as created by Create->P&R Objects->P&R Boundary

    Without this I get some pretty clear warnings in the CIW:

    WARNING: (OALEFDEF-90016): Design ADDFHX1 abs1 does not have a snapBoundary. Searching for a prBoundary.
    WARNING: (OALEFDEF-90017): Design ADDFHX1 abs1 does not have a prBoundary. Searching for a layer-purpose pair.
    WARNING: (OALEFDEF-90018): No shape on layer purpose pair found in the design ADDFHX1 abs1. The ORIGIN, FOREIGN, and SIZE statements will not be printed. Ensure that you have defined the snapBoundary, PRBoundary, or geometry on LPP (boundary, boundary) in the cellview.

    With it, I do get the ORIGIN, FOREIGN and SIZE entries.

    I do find that if you have the prBoundary/boundary layer purpose, it still works, although that's really not the supported flow nowadays. If you've used a different lpp (e.g. prBoundary/drawing) then it doesn't work and you get the warnings above.

    Regards,

    Andrew.

  • anandmohan

    Hi Andrew,

    I followed your instructions and is working fine now. Thank you very much.

    Regards
    Anand

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.