+ Post New Thread
Results 1 to 5 of 5
  1. #1
    Member level 1
    Points: 272, Level: 3

    Join Date
    Jul 2017
    Location
    KANPUR
    Posts
    33
    Helped
    0 / 0
    Points
    272
    Level
    3

    calibre pex warnings: The ground net "VSS/VSSO" defined in PEX NETLIST

    I compared LAYOUT vs CLD netlist of UART design by RTL code and gds exported into Virtuoso.
    There are no error but following warning is coming during PEX in calibre .

    "The ground net "VSS/VSSO" defined in PEX NETLIST statement is not a valid GND net in the design."

    what is the cause of this warning ,How to remove this warning.

    In LAYOUT VSS,VSSO VDD ,VDDO dc supply are used for PADs and VDD ,VSS are common to both for PADs and Chip.
    VSS, VDD are supplied to both Core-Ring and to PAD-ring by PADs defined in PDK for supply to both PAD-RING and CORE-RING.
    scl pdk is used for design.

    •   AltAdvertisement

        
       

  2. #2
    Super Moderator
    Points: 51,886, Level: 55
    Achievements:
    7 years registered
    erikl's Avatar
    Join Date
    Sep 2008
    Location
    Germany
    Posts
    8,091
    Helped
    2667 / 2667
    Points
    51,886
    Level
    55

    Re: calibre pex warnings: The ground net "VSS/VSSO" defined in PEX NETLIST

    Depending on your process (PDK) you might need an extra connection between VSS(O) and GND, either a direct connection or via a SUBSTR-SUBTAP symbol (or similar name).


    1 members found this post helpful.

    •   AltAdvertisement

        
       

  3. #3
    Member level 1
    Points: 272, Level: 3

    Join Date
    Jul 2017
    Location
    KANPUR
    Posts
    33
    Helped
    0 / 0
    Points
    272
    Level
    3

    Re: calibre antenna drc rule check warnings:

    these warning are coming during antenna rule check in calibre.
    these warning are harmful or not.
    how to remove these warnings.
    warnings
    ACUTE angle on layer M2 at location (64.11,0.99) in cell subil_pngatebuff_ESD122.
    ACUTE angle on layer M2 at location (64.11,0.99) in cell subil_pngatebuff_ESD1.
    ACUTE angle on layer M2 at location (64.11,0.99) in cell subil_pngatebuff.
    ACUTE angle on layer AA at location (28.73,325.56) in cell subil_midconer2.
    ACUTE angle on layer AA at location (34.43,317.94) in cell subil_midconer2.
    ACUTE angle on layer AA at location (36.86,315.64) in cell subil_midconer2.



    •   AltAdvertisement

        
       

  4. #4
    Super Moderator
    Points: 51,886, Level: 55
    Achievements:
    7 years registered
    erikl's Avatar
    Join Date
    Sep 2008
    Location
    Germany
    Posts
    8,091
    Helped
    2667 / 2667
    Points
    51,886
    Level
    55

    Re: calibre antenna drc rule check warnings:

    Quote Originally Posted by sanjaysharmaiitk View Post
    ... these warning are harmful or not.
    They are undesired and possibly could provoke a rejection of your design.

    Quote Originally Posted by sanjaysharmaiitk View Post
    how to remove these warnings.
    Usually such warnings (angle < 90° , even just a tiny bit less, invisible) result from usage of an incorrect grid.

    Set the correct grid and re-grid your design. If there aren't too many acute angle warnings, you could do the re-gridding manually.



  5. #5
    Advanced Member level 2
    Points: 5,604, Level: 17
    Achievements:
    7 years registered

    Join Date
    Feb 2008
    Posts
    548
    Helped
    181 / 181
    Points
    5,604
    Level
    17

    Re: calibre pex warnings: The ground net "VSS/VSSO" defined in PEX NETLIST

    "The ground net "VSS/VSSO" defined in PEX NETLIST statement is not a valid GND net in the design."

    It looks like you defined two ground nets but put no spaces or commas etween the names, but the slash - so PEX thinks this is one net name, and says it's invalid (I think ground net names should not contain slashes - slashes are usually used as hierarchy separators).
    Leave only one net as ground (such as VSS), see what happens - to check my theory.



--[[ ]]--