Glade Reference
The Schematic Editor is activated when a cellView with viewType 'schematic' is opened. The Schematic Editor is used to create and edit schematics. These can be netlisted for use in a simulator such as Spice, or to create layout in Glade.
A library of symbols must exist in order to place and wire devices in the schematic. A library of simple pins and power/ground symbols is provided in the 'basic' library. This is automatically loaded when Glade starts. The 'basic' library is required by the Create Pin command in schematics.
Schematic entry and editing does not require any specific technology file information - schematics use predefined system layers. For portability, it is recommended that the user does not use non-system layers in schematics or symbols.
The typical steps involved in creating a schematic are as follows:
Schematic editing shares many common menu entries with layout and symbol editing. Those specific to schematic are the Create and Check menus.
Displays the Create Instance dialog, which can be shown or hidden by the F3 key. An outline of the device instance is shown as the cursor is moved.
Creates a wire, starting at the initial point (either the current cursor position, if infix mode is on) or by a first point entered by a left mouse click. Subsequent left mouse clicks add wire end points; use the backspace key to back up an entered point, and use the return key or double click to end a wire. If the wire starts or ends on another wire midpoint, a solder dot is automatically entered at the junction of the two wires. If the wire starts or ends on the endpoint of an existin wire, the two wires will be merged into a single continuous wire. If you click on a pin (either an IO pin or a device pin) or click on a wire, the wire entry is ended. The snap direction can be set in the Create Wire dialog.
Snap Angle sets the snap direction when entering a wire. HV means the wire will be created with a horizontal segment followed by a vertical segment. VH means the wire will be created with a vertical segment followed by a horizontal segment. 90 means the wire will snap to manhattan directions. 45 means the wire will snap to 45 degree directions. Any means the wire can have any direction. Horiz means the wire can only be entered in a horizontal direction. Vert means the wire can only be entered in a vertical direction. Wire Width sets the display width of the wire. A value of 0 or 1 means 1 pixel wide. Net can be used to preset the net name for the wire; it is not necessary in most cases as subsequent Check CellView command will extract connectivity.
Creates a solder dot at the point entered by the cursor. If you want to connect two crossing wires, use a solder dot, else they are assumed to be bridging and not connected.
Creates a label for the wire. The Create Label dialog will be displayed.
The Create Label dialog allows the name of the Label Text (i.e. net name) for the wire to be entered, along with Height, Orientation, Presentation. The Label Use should be 'normal label' label, and the Label Type 'normal'.
Displays the Create Schematic Pin dialog.
A list of Pin Name(s) can be entered, separated by spaces. As each pin is positioned by left clicking, a pin of the first name in the pin name list is created, and that name is removed from the list of pin names. The pin Direction and pin Use can also be specified. Pins can be mirrored or rotated during entry. A pin is actually an instance of a pin from the 'basic' library; if this library cannot be opened when Glade starts an error will be reported and Create Pin will fail.
This command creates a symbol view from the existing schematic.
Create CellView creates a symbol shape, large enough to accomodate the input pins positioned on the left, the output pins positioned on the right, and inout pins on the top of the symbol. NLP labels for the instance name, cell name etc. are created automatically along with a template NLPDeviceFormat property for netlisting.
The Check CellView command must be used after creating or editing a schematic to extract connectivity e.g. for netlisting. Various checks are performed including floating wires, floating pins and shorted wires. If errors are found, the number is reported and markers are written on the marker layer to the cellview.
Displays the marker browser. Errors can be stepped through and are automatically zoomed to.
Clears all marker errors.
Displays the Check Options dialog.
The Check Options dialog sets the Check CellView options. For each option, you can set the check to either ignore the result, issue a warning or issue an error. Floating wires/solder dots checks for any wires or solder dots that are unconnected to device pins or external pins. Floating Input Pins checks for pins with direction Input that are not connected to device pins. Floating Output Pins checks for pins with direction Output that do not connect to device pins. And similarly Floating IO Pins checks for pins with direction Inout that are not connected to device pins. Shorted Output Pins checks for output pins of devices that share a net with other output pins of devices. Duplicate Instance Names checks for instances with the same name.
The Map Devices menu allows mapping a cell in the schematic to a different named cell (usually pcell) in the layout.
In the above dialog, the entries in the Device Name section of the table map a cell such as cnm25modn in the schematic to a cell called cnm25modn_m in the layout. Entries in the Instance Name section can map specific instances of a cell to a different layout cell.
Device mapping can be set up to pre-seed the dialog using entries in the Glade technology file:
MAP cnm25modn TO cnm25modn_m layout ;
MAP cnm25modp TO cnm25modp_m layout ;
MAP cnm25cpoly TO cnm25cpoly_m layout ;
To create a layout view from a schematic, use the Create Layout command.
The target cellView is specified using the Library Name / Cell Name / View Name fields. If Create m factor instances is set, then if a schematic instance has an integer property 'm', then multiple instances of the cell will be created in the layout based on the value of the property, and the m property is not passed to the layout pcell. If not checked, the m property is passed to the layout pcell, if the pcell is required to handle this itself.
Scale Factor is used when the placement method is Schematic. It scales the instance origin coordinates by the factor, so the resulting layout mimics the schematic. The actual value required will depend on the target library cells.
Utilisation is used to create the cell boundary layer in the resulting layout view. The area of all the layout instances is summed, and divided by 100/utilisation%. If Width is specified, the cell boundary will be rectangular with the specified width, and height will be computed from the area/width. If Height is specified, the cell boundary rectangle will have the specified height and the width will be computed from the area/height. If both Width and Height are speciified, then the cell boundary rectangle will use the specified width and height.
Placement method can be one of Schematic, Area or Group. Schematic placement uses the relative coordinates of the schematic instance origins to place the layout cells. Area arranges the layout cells by type (PMOS/NMOS/resistor/capacitor). Group will place cells according to group properties on the schematic.
The pin field allows pin width, side and layer to be specified for each pin. Pins are placed abutting the cell boundary rectangle according to their side.
Create Group takes a selected set of instances and creates a group for group placement in Gen Layout. A property with name "group" and value given by the group name will be created on all the selected instances.
Add to Group will add selected instances to the specified group.
Remove from Group will remove the selected instances from the specified group.
Delete Group will delete the specified group. All instances of that group will have the property named "group" removed.
Rename Group
Rename Group will take an existing group and rename it.
Edit Group allows setting the pattern for the layout of the group's instances.
The instances of the group are displayed as a grid, initially 2 rows. The Rows and Cols spinboxes can be used to change the generated array of devices; the size of the array is always greater than the number of actual instances. Group Name sets the current group to edit. To change positions of instances, left click and drag an instance to a new position; the source and destination instances are swapped.
The group patterns are saved to the schematic cellView as a property with name equal to the group name. The value of this property is a string of the form "I0.0_0_0,I0.1_0_1" etc. where each field delimited by a comma represents the instance name, the row number and the column number, delimited by an underscore.
Link to Layout sets the mapping from schematic to layout. If you have two windows open in MDI mode, one for the schematic and one for the layout, this allows cross probing between layout instances and schematic instances. The corresponding instances are selected in the linked cellview, and are highlighted. Note tha tlayout linking is automatically carried out when Gen Layout is run.
Clears highlighted instances.
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