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Extract Step in Standalone Abstract Generation
The Extract step is the second step in the abstract generation process, traces the connectivity between shapes and terminals, starting at the pin purpose shapes created in the Pins step. The shapes created during extraction are created on the purpose net at the top level of the extract view.
Abstract Generator performs the following functions during the Extract step:
- Extracts each terminal net, one shape at a time.
- Constructs the correct database model for strong, weak, and must-join pins.
- Creates library process antenna information for custom blocks and standard cells.
- Select one or more cells in the main window and click the Extract button. Alternatively, select Flow – Extract. The Flow – Extract command runs as far the Extract step for the selected cells.
- When you select the command, the Running Form is displayed. Use this form to view and modify the bin options relevant to the Extract step and any prior steps that must be run.
- Click Run to run the step when you are satisfied with the options settings.
The Percent Complete message box reports the progress of the step.
Abstract Generator processes the cells as far as the Extract step, creating an extracted view, along with any of the predecessor views required.
If you have not already generated pins for the selected cells, Abstract Generator automatically runs the Pins step prior to running the Extract step.
You can enable or disable extraction for signal and power nets or specify the extraction to be solely performed for antenna data. The default settings depend on a cell’s bin type, and by default, all bins except the Core bin have extraction turned off. When the Extract step is complete, Abstract Generator places a graphical icon against the cell to indicate the status of the Extract view that was created. Abstract Generator automatically detects shapes placed in WSP regions and ignores these shapes during net extraction. Therefore, no pins are created for such shapes. You do not need to specify extraction limits for antenna data calculation.
Running Form
The Running form appears whenever you run a flow step. The form is a modified version of the Bin Options form but offers access only to those bins and options relevant to the step or steps about to be run.
The label in the title bar indicates which step is about to be run, such as Running Step Pins indicate that the Pins step would be executed. The Step Selector provides access only to the options associated with those steps. The Bin Selector lists only those bins in which the selected cells reside. See Setting Bin Options in Abstract Generator.
Processing Cells in Different States
When you press a toolbar button to perform one of the main flow steps, Abstract Generator checks the selected cells to ascertain which steps have to be run for each cell.
Suppose you have two cells selected in the Cell pane, Cell1 and Cell2. Cell1 has run as far as the Pins step and Cell2 as far as the Extract step. If you now run the Abstract step for both the cells, the following steps also must be run:
Consequently, the Running form will include all the options related to the Extract and Abstract steps. You can access options of a step that has already been run. If you change an option for a step that has already been run for a particular cell, that step and all downstream steps for that cell will become invalid.
In the example above, you can also access the Pins options, even if all the cells have valid pins views. Changing one of the Pins options will render the existing pins and extract views for Cell2 invalid, and these steps will be rerun for that cell.
Related Topics
Specifying Layers and Geometries for Extraction
Exclude Metal Purpose Blockages in Layout Designs
Pins Step in Standalone Abstract Generation
Abstract Step in Standalone Abstract Generation
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