Sonnet - Create Sonnet em View
You must create a Sonnet em View from a layout view of a cell in Virtuoso in order to run a Sonnet simulation on your layout. This way the original layout is not affected. Also, when using only a part of your original layout, it is easier to determine exactly what you are analyzing by having a separate Sonnet em layout.
The definition of a “cell” in the Cadence Virtuoso environment is equivalent to the “circuit geometry” in Sonnet. When “cell” is used in the Sonnet environment, it is referring to the smallest part of the analysis grid used in subsectioning your circuit.
To create the Sonnet em View, you open the layout window and select Launch - Sonnet to load the Sonnet menu. Then in the Sonnet menu, you select Sonnet - Create Sonnet em View, which opens the Create Sonnet em View from Layout View dialog box which allows you to specify parameters for the Sonnet em View you wish to create. While there are advanced controls that allow you to select parts of your layout with a great deal of precision, normally you will just translate the whole cell view and will not have to use the other options. The controls are detailed below.
Device Preset: To streamline the Cadence Virtuoso Interface setup, select a device preset from this drop list to change the default settings to typical settings used for that type of device. The presets available in the list are dependent on how your system administrator has set up your interface. If you do not wish to use all of the settings in a preset, you may make changes before performing the analysis.
This section of the dialog box displays the Library, Cell, and View of the original circuit in Virtuoso. These values are displayed but may not be changed.
The Library, Cell Name and View of the Destination cell, which in this case is the Sonnet em View, are listed in this section of the dialog box. You may edit the library and cell of the destination; however, we recommend keeping the default destination Library and Cell Name.
This section of the dialog box is one of three tabs in the bottom half of the dialog box. This tab allows you to identify what parts of the original layout you wish to include in your em analysis. The contents of the tab changes based on the selection of your Analysis Target.
Whole Cellview: If you wish to select everything in the layout, click on the Whole Cellview button. This option will copy the entire layout into the Sonnet em View.
Selected Objects: Select this option if you wish to choose which objects in the layout are copied into the Sonnet em View. Click on the appropriate button to select that object to copy. A count of selected objects is updated each time you choose an object type. You may also use a SKILL script to select the desired objects by entering the function name in the text entry box to the left of the Execute Function button, then clicking on the Execute Function button. To clear all selected objects, click on the Deselect All button. If no objects were selected when the Create Sonnet em View dialog box was opened, then all objects will be selected by default.
Defined Region: Select this option if you wish to select a rectangular portion of your layout to copy. There are instructions for setting the bounding box in the dialog box. Objects within the bounding box are copied. For objects intersecting the bounding box, you may choose to translate the whole object, or chop off the portion of the object appearing outside the bounding box.
Present Zoom: Select this option is you wish to select the portion of your layout that is presently shown in the layout window. The present view sets the bounding box and objects within the bounding box are copied. For objects intersecting the bounding box, you may choose to translate the whole object, or chop off the portion of the object appearing outside the bounding box.
If you wish to run a SKILL script in the Virtuoso environment, click on the Run Functions tab.
Changes are made to objects when the Sonnet em View is created. You may choose to run a SKILL file before Sonnet makes any changes, such as flattening the layout or you may run a SKILL file after Sonnet makes the changes, such as merging vias. You specify the SKILL file in the upper text entry box and a function name and arguments for the function in the text entry box below if they are required. The specified SKILL file will be run at the appropriate time before the Sonnet em View view is created.
Convert Certain Shape Objects to Polygons: If you wish you may define the number of points used when converting donuts, ellipses and circles to polygons in the translation, click on the Options tab. Enter the number of points you wish to use when you convert the curved shapes. The higher the number of points, the more closely the shape of the polygon adheres to the original object.
Flatten P-cells: Selecting this option invokes a skill function which flattens all P-cells and structures within the hierarchy up to the number of levels entered in the Number of Hierarchy Levels text entry box.
Preserve Pins: Selecting this option carries over all Cadence pins drawn in the layout over into the Sonnet em View. Any that are shape pins with pin purpose, will be converted to ports during the translation.
Preserve ROD objects: Selecting this option preserves any relative object designs (ROD) in your layout and copies them to the Sonnet em view.
Layout Scale Factor: This options allows you to control the size of the Sonnet em View layout by scaling the original design. All of the original circuit dimensions are multiplied by the number entered to create the Sonnet em View circuit. A scale factor of one creates a circuit the same size as the original. You may enter values of less than one to decrease the size of the circuit and greater than one to increase the size. This is a floating point number.