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Electrical Scalar Terminal Editing

At the top of the panel is a Terminal Index numeric entry area. This can be used to change the terminals index number, and therefor order in subcircuit references. The renumbering is a two step process:

  1. The present terminal is removed, and the remaining terminals are renumbered, using unique and contiguous new index values (zero based).

  2. The terminal is reinserted at the given index. The terminal that had that index and those larger will have their index values incremented.

Changing the index of a scalar terminal does not update the multi-contact terminals! The index values used in the bus terminals may require compensating changes.

Just below is the Terminal Name text entry area. This will contain the name of the terminal, which can be edited by the user. The entry can be empty, in which case Xic will generate a name.

The Has physical terminal check box should be checked if the terminal will have a corresponding contact point in the physical layout. Setting this check box will allocate the internal data structure needed to maintain the association. In most cases, this will be required. It is not required if, for example, the user at this point is only concerned with a schematic for simulations. The terminal can be edited and this box checked at a later time, when the user is ready to add a layout. The box is never checked for terminals used in the schematic for special purposes that are perhaps related to simulation, that have no ``real'' implementation in the layout.

When the Has physical terminal check box is checked, the Physical group is un-grayed. There are two controls in this group.

Layer Binding
The Layer Binding menu provides a layer name that is a hint used by the extraction system when placing the physical terminal in the layout. This is set by Xic after extraction, and if correct should not be changed. It is set by the user when a terminal is manually placed, to resolve ambiguity about which layer the terminal connects to.

Location locked by user placement
When a terminal is manually placed, the Location locked by user placement check box will become checked. This indicates that the FIXED flag is set in the terminal. Terminals with this flag set will never be moved by Xic during extraction/association.

The location and layer must be correct or association will fail. Although Xic will automatically place terminals, at times this will fail and the user will have to place some terminals manually to obtain correct or complete association.

Below the Physical group are check boxes for setting some binary options.

Set contact by name only
This check box, when checked, sets the BYNAME flag in the terminal which changes its interpretation in the schematic (it has no effect in physical mode). Ordinarily, a terminal is placed on a ``connection point'' of a wire net in the schematic (i.e., a vertex), or a device or subcircuit contact point. Association of the terminal to that wire net is by location. If there is no underlying connection point, and the terminal has an assigned name, Xic will then attempt to add the terminal to an existing net with a matching name. If this flag is set, then the initial attempt to connect the terminal by location will be skipped. This is useful if the terminal is to be made invisible, to avoid accidental connections. The scalar wire nets can be named with the Node (Net) Name Mapping panel from the side menu (see 7.11).

Set terminal invisible in schematic
This check box, when checked, sets the SCINVIS flag in the terminal which prevents the terminal from being displayed in schematics. This is for terminals that are used only as bit connections for a multi-contact connector. Recall that every bit in a multi-contact connector is a scalar connector, that must exist if a connection is to be established. If connectivity is to be provided only via the multi-contact connector, the individual bits are visually superfluous and clutter the display. However, they can be made invisible in the schematic with this flag. They should probably also have the BYNAME flag set as well, so that they don't make an unintended connection by location. The setting has no effect in physical mode.

Set terminal invisible in symbol
This check box controls the analogous SYINVIS flag, which when set causes the terminal to be invisible in the symbolic representation, if any. This flag will almost always track the state of the SCINVIS flag, but this is not an absolute requirement. It is possible for a schematic to use individual bits for connections, whereas the symbol uses a multi-contact terminal, or vice-versa.

next up previous contents index
Next: Physical Terminal Editing Up: The Terminal Edit Pop-Up: Previous: The Terminal Edit Pop-Up:   Contents   Index
Stephen R. Whiteley 2022-05-28