Postprocessing a Magic Design

Cadence and Magic use different file formats for the storage of design data.
Interchange is possible via a common GDS2 stream format.

Procedure

• go to magic directory

    hart<~>$ cd ~/design/fcde/magic/design
  

• translate the top level magic file to cadence format

    hart<~/design/fcde/magic/design>$ do_cmos035_desin <topcell>
  

The Magic layout editor supports simple on-line DRC.
The Cadence layout editor supports a DRC post-processor.

Magic designs must pass the more stringent Cadence DRC before they will be accepted for fabrication.

Procedure

• change to directory containing cadence files

    hart<~/design/fcde/magic/design>$ cd ~/design/fcde/cadence
  

• start cadence

    hart<~/design/fcde/cadence>$ cds
  

• use the library manager for library, cell and cellview manipulation

    Tools -> Library Manager...
  

  within the library browser the left hand mouse button is used for navigating around the library structure while the middle mouse button provides access to the commands used to manipulate the libraries, cells and cellviews.

  • open the imported design for edit

    use the mouse to select Library: fcde, Cell: <topcell> and View: layout then invoke the open command -

      File -> Open...
    

• perform DRC

    Verify -> DRC...
  
      DRC
        Switch Names      [ drc_shape? offgrid?       ]
        Rules File        [ divaDRC.rul               ]
        Rules Library     [ ]  [                      ]
      OK
  

  • If performing a DRC on a full design including black box (abstract) pad cells, you will probably have to perform the DRC on the core area only in order to avoid spurious DRC and ERC errors.

• Certain errors cannot easily be removed by modifying the original magic design. In such cases you will have to modify the mask layers directly using the Cadence layout editor.