When the Place button in the panel or in the Edit Menu is active (the two buttons show the same status), and the user is not being prompted for a cell name (the ``master'') to place, the current master can be instantiated at locations where the user clicks (``place mode''). The bounding box of the cell is ghost-drawn and attached to the pointer. The orientation and size of the instance are set by the current transform. If the Cell Placement Control panel is dismissed the place mode, if active, remains active. The place mode can be exited with the Esc key, or by pressing the Place button (either one) a second time. The panel is not popped down when place mode is exited.
From the Edit command in the Edit Menu, if one holds down Shift while selecting one of cells from the history list, the Cell Placement Control panel will appear with that cell added as the current master. This applies to cell names and not the ``new'' entry. This is a quick backdoor for instantiating cells recently edited.
In electrical mode, when a connection point of a device or subcell is near another connection point, it will snap to that location and a small dotted box will be drawn around the point. This facilitates placement of devices and subcircuits in the schematic. While the Shift or Ctrl keys are held, this feature is disabled.
Cells can be placed individually, or as arrays in physical mode. The reference point of the cell, which is the point in the cell located at the pointer, can be set to either the cell's origin, or the lower left corner of the untransformed bounding box, while in physical mode. In electrical mode, the cell reference point is always set to the location of the reference terminal, which is usually the first terminal defined. If the cell has no terminals, the cell origin is the reference point. An electrical cell should always have terminals (assigned with the subct command in the electrical side menu) if it is to be part of the circuit, and not some kind of decoration or annotation.
The cell currently being placed, the ``master'', can be selected in several ways. A list of masters is kept, and can be viewed with the menu button in the Cell Placement Control panel. Pressing and holding button 1 with the pointer on the menu button issues a drop-down menu, whose entries are highlighted as the pointer passes over them. A selection is made by releasing button 1 over one of the selections. Pressing the New button in this menu brings up a dialog box which allows the user to enter a new master name. If a selection can be found in the various panels that provide file or cell selection, that selection is pre-loaded into the dialog as a default. Each of these sources is tested in order, and the first one that is visible and has a selection will yield the default cell name.
The first time the place panel comes up, the user is prompted for the name of a cell, just as if the New menu button was pressed.
The name provided can be a file containing data in one of the supported archive formats, the name of an Xic cell, or a library file. If the name of an archive file is given, the name of the cell to open can follow the file name separated by space. If no cell name is given, the top level cell (the one not used as a subcell by any other cells in the file) is the one opened for placement. If there is more than one top level cell, the user is presented with a pop-up choice menu and asked to make a selection. If the file is a library file, the second argument can be given, and it should be one of the reference names from the library, or the name of a cell defined in the library. If no second name is given, a pop-up listing the library contents will appear, allowing the user to select a reference or cell.
The place panel is sensitive as a drop receiver. If a file name is dragged over the place panel and the mouse button released, the behavior is as if the New button in the masters menu was pressed, and the file name will be loaded into the dialog window.
The number of masters saved in the pull-down menu can be specified with the variable MasterMenuLength, which defaults to 25. This may not be optimum for some screen resolutions, and it does no good if the menu extends off-screen. To set the length to 15, for example, one would type (outside of any command)
!set MasterMenuLength 15This must be entered before the place panel is popped up for the first time. This command would logically be included in a startup script. The list used in the drop-down menu consists of the most recent masters specified, either with the New button, or through the Master button in the Cells Listing or Files Listing panels from the File Menu.
Two mutually exclusive buttons select whether the cell reference point is the cell's origin (Origin button), or the lower left corner of its bounding box (Lower left button). This is the point that is attached to the pointer, and corresponds to where the user clicks to place the cell. These buttons have no effect in electrical mode, as the reference point is always the device or subcircuit's reference terminal.
When the Use Array button is active, cells will be placed as arrays, governed by the currently set array parameters. The array parameters can be entered into the four text fields below, only when the Use Array button is active. Arrays are allowed in physical mode only. If this button is not active, single cells are placed.
When the Replace button is active, existing cells are replaced with the new master when clicked on. and no cells are placed if the user clicks in the area outside of any subcells. When a cell is replaced, the placement of the new cell is determined in physical mode by the setting of the Origin/Lower Left buttons in the place panel. When Lower Left is active, the lower left corner of the replacing cell corresponds to the lower left corner of the replaced cell, otherwise the cell's origins are used. In electrical mode, the reference terminal (the first connection point) is always placed at the same location as the reference terminal of the replaced cell. In either case, any currently active transformations are performed in addition to the transformations of the replaced cell on the new cell.
Cells can be placed or replaced only when place mode is active, i.e., when the Place button in the Cell Placement Control pop-up or the Place button in the Edit Menu is active.
The Dismiss button will retire the Cell Placement Control panel. The place mode, if active, is not terminated, and additional cells can be placed. Place mode is terminated by pressing the Esc key, or by pressing the Place button in the Edit Menu a second time.