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Generating Symbol View

Now the inv cell has layout, extracted, and abstract views. As a lowest level library cell, it needs one other important cell views. Symbol view:
This view is necessary for schematic design entry. It is the symbol which represents the cell. If you perform design entry by verilog netlist, you don't need to generate symbol view.

To generated symbol view for inv:
  1. Start Cadence using "icfb".
  2. In CIW menu, select File -> New -> Cellview ... A create New File form appears. Fill in your library name for Library, "inv" for Cell, and "symbol" for View, and select "Composer-Symbol" for Tool, then Click "OK". This brings out a Composer-Symbol Editing window.
  3. In Composer menu, select Design -> Create Cellview -> From Pin List ... This brings out a Cellview From Pin List form.
  4. Type "a" as Input Pins, "y" as Output Pins, "inv" as Cell Name. Change View Name to "symbol". Unselect Edit Options and click "OK".
  5. Choose Replace if it tells you that the symbol already exists.

    Comment: Pin names in symbol view must be exactly the same as pin names in layout view or you will experience huge problems when doing auto placement and routing.

    Comment: Default power pins vdd! and gnd! should not appear in symbol view.
The symbol view will be generated and brought out in symbol editing window (shown below).

To tailor made your own symbol view, you can use the built-in commands. Open your symbol view, click Add -> Shape -> Line You can then draw your desired symbol view. The bubble can be drawn using the Add -> Shape -> Circle Once you're done, you can delete unwanted lines and move the pins to desired positions. A symbol for inverter can be like this:

You may close symbol window after you modify your symbol view.

Refer to 'Preview Library Development Reference' and 'Composer Design Entry reference' for more information about abstract and symbol generation.
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