Selecting Objects

You can use the following methods to select an object in the EPIC window.

Move the mouse over an object in the editing area, and click the left mouse button. This method is usually the easiest.
Display an object list in the EPIC List dialog box, and click the left mouse button on an object.
Type the Select command in the EPIC Command Line dialog box along with the appropriate arguments. See the “Select” section of the “Command Line Syntax” chapter for details.
Use the Find dialog box. See the “Selecting Objects with the Find Dialog Box” section for details.

In some cases, unpolished components for example, you can only select from a list or from the command line, because there is no graphical representation of the object in the editing area.

You can select any of the following objects.

Sites
Site pins
Components
Component pins
Nets
Paths
Macros
Switch box pins
Wires (pinwires, long lines, local lines)
Route lines
Object layers
Constraints
Rats nest lines

When you select an object, it changes color and its name and attribute are displayed in the history section of the window. When you select a used wire (pinwire, long line or local line), the name of the net using the wire is displayed in the history area. When you select a used component pin (or net pin), the history area shows the pin name, the name of the net to which this pin belongs, and the delay time from the net source to this pin.

When you select additional objects, they also change color. You can select multiple objects of the same type and multiple types of objects. However, the objects you select must be appropriate for the action you are performing.

When you select an object that is already selected, it is deselected. In most cases, objects are deselected after a command has been performed on them. For some commands, you can control whether the objects remain selected or are deselected after the command has been performed.

You can perform the Clear command at any time by selecting it from the View menu, entering Clear in the EPIC Command Line dialog box, or by clicking the Clear push button. The Clear command deselects all current selections. It can be helpful if you want to perform an editing function, but suspect that you may have left some extraneous objects selected in the editing area. By using the Clear command before another command, when you select objects, you are starting the operation with no extraneous objects selected. You can also check current selections by looking in the Locator Area, which displays selected objects even if they cannot be seen in the editing area.

After you select the appropriate object or objects, initiate the command through any of the command means available in EPIC: a menu, push button, command alias, “hot key,” command script, or typing the command in the EPIC Command Line dialog box.

Selecting Objects with the EPIC List Dialog Box

The EPIC List dialog box, shown following, displays an alphabetical list of components, nets, paths, layers, constraints, or macro names in your design. By displaying the specific list and selecting entries, which can be scrolled vertically or horizontally, you can perform a number of operations.

Figure 3.5 EPIC List Dialog Box

Use the option button at the top of the dialog box to specify what type of items appear in the list. You can display the following.

Routed and unrouted nets
Placed and unplaced components
Placed and unplaced macros
Layers
Paths
Constraints

If the complete list does not fit in the EPIC List dialog box, a vertical scroll bar appears at the right of the list. If any of the entries are too wide to fit in the dialog box, a horizontal scroll bar appears. You can view wide entries by either using the horizontal scroll bar or by resizing the dialog box. To resize, position the cursor on any corner of the dialog box. With the mouse button pressed, drag the corner to the desired size. For Motif, resizing does not work if your file contains this line.

Mwm*transientDecoration: -resize

Remove the line or comment it out.

You can select list entries as objects to be edited. When you select a name in the list, you select the object with that name, and the object changes color in the editing area. You can then perform all of the same EPIC operations on the selected objects that you could perform if you selected the object directly in the editing area.

The operations you can perform on objects you select from the EPIC List dialog box are as follows.

Menu Option (Workstation)	Menu Option (PC)	Result, if Selected
All Nets	Nets All	Changes the display to a list of all of the nets in the design.
Routed Nets	Nets Rt	Changes the display to a list of all nets that are completely routed.
Unrouted Nets	Nets Unr	Changes the display to a list of all nets that are partially or completely unrouted.
All Components	Comps All	Changes the display to a list of all components in the design.
Placed Components	Comps Pl	Changes the display to a list of those components that have been placed.
Unplaced Components	Comps Unp	Changes the display to a list of those components that are unplaced (not fixed at a particular location).
All Macros	Macs All	Changes the display to a list of all physical macros in the design.
Placed Macros	Macs Pl	Changes the display to a list of those physical macros that have been placed.
Unplaced Macros	Comps Unp	Changes the display to a list of those physical macros that are unplaced (not fixed at a particular location).
Layers	Layers	Changes the display to a list of all EPIC layers.
Paths	Paths	Changes the display to a list of all paths that have been defined within the design.
Constraints	Pcfs	Changes the display to a list of all constraints that have been defined in the .pcf file or have been added during this EPIC session.

Selecting Objects with the Find Dialog Box

The Find dialog box appears when you select the Find button or choose the Find option from the Tools menu. Pushing the option button at the top of the box, and typing in the name of the object (for example, RESET) allows you to select a specific net, component, site, pin, or macro and locate it in the EPIC editing area.

Figure 3.6 Find Dialog Box

Find	Determines the type of object for which you are searching. When selected, it posts this option menu from which you can select a type.
Name	The name of the component, net, site, pin, or macro that is the object of the search.
Auto Pan	Automatically pans to the object of the search, if you are zoomed in when you select Find. Otherwise, the object will only be selected.
Auto Clear	Clears all previous selections; only the item being searched for is selected.

As an alternative to using the Find dialog box, enter the Find command in the EPIC Command Line dialog box. See the “Find” section of the “Command Line Syntax” chapter for details.

Notes About Selecting

You can select objects described in this section using the EPIC List dialog box to display the applicable list, then choose the name of the object(s). You can also select objects by entering a Select command in the EPIC Command Line dialog box see the “Select” section of the “Command Line Syntax” chapter.

You cannot select unplaced components and macros in the editing area, because they are not there. You can select them using the EPIC list dialog box and the Select command line command. A path cannot be selected in the editing area either.
You can select object layers, such as the components layer or the ratsnest layer. Layers are selected in order to change attributes for all layer members, for example, to display all components in green.
When you select a component, net, or macro name in the EPIC List dialog box, it is highlighted and the corresponding object changes color in the editing area. When you select a component, net, or macro in the editing area, it changes color and its name appears selected in the EPIC List dialog box. Selecting a constraint in the List dialog box does not cause a corresponding highlight in the editing area. The only operation that you can run on constraints is TRACE. See the “TRACE” section.
Switch box pins are selectable. When you select a switch box pin, the display shows the allowable connections from the selected pin to other pins within the switch box. You cannot perform any other operations on a selected switch box pin.
You can only display the connections for one switch box pin at a time. All other paths are cleared when a new switch box pin is selected within a single switch box.
When you select a ratsnest line, the entire net containing the ratsnest line is highlighted, and the net is selected.
The following extended selections can be made by pressing the Shift key while you make your selection.
Select a partially or fully routed net by pressing the Shift key while selecting any route segment on the net, just as when you select the net from the EPIC List dialog box.
Bring up the Logic Block Editor by pressing the Shift key while selecting a component.
For architectures that allow route-throughs, highlight all available route-through paths for a site or component pin by pressing the Shift key while selecting the pin.
Select a macro by pressing the Ctrl key while selecting a component contained in the macro.

Adding Objects

When you add objects to your design, these new objects become part of your design's database. Use the Add command to perform these functions.

Create new components
Create a new net
Add a component pin to an existing net
Add a macro to the design
Define a path

You add objects to the database by selecting appropriate objects, then using the Add command.

The Add command can be performed in any of the following ways.

Select Add from the Edit menu.
Select the Add push button.
Enter add in the EPIC Command Line dialog box.

NOTE

Objects cannot be added if the design is in the No Logic Changes Mode. Edit modes are discussed in the “Opening an Existing Design” section of the “Getting Started” chapter.

Adding Components

To add new components to the database use this procedure.

Select vacant sites in which to place the new components.

You can select any type of site, for example, CLB, IOB, tristate buffer, pull-up resistor.
Select Add from the Edit menu.

The sites become components, and these new components can be connected to other components in the device.

The Component Attributes dialog box may appear on the screen for each newly created component. Whether the dialog box appears or not is controlled by the Automatic Post main window attribute, see the “Main Window Attributes” section. Each dialog box shows the name of the new component and the name of the site in which the component is placed.
You can edit the component attributes in the dialog box and click OK or Apply to apply them, or Cancel to close the dialog box and maintain the defaults. See the “Component Attributes” section for details.

Notes on Adding Components

When you add a component, the name assigned to the new component is in the format $COMP_number, where number is a number assigned to each new component. Numbering starts at 0 and increases by one for each new component. For example, if you already have 100 components and you add a component at site HF, the new component is named $COMP_101. The next component, added at site CF, is named $COMP_102, and so on. You can change the component's name by modifying the Component Attributes dialog box.
Any characters special to the EPIC command interpreter must be preceded by a backslash (\) escape character when used in a component name. Special characters are quotation marks (“ or `) * ; ? # - (leading dash). The restriction only applies to commands entered at the command line or those in an EPIC command script file; the special characters may be entered in the Component Attributes dialog box without the escape character.

NOTE
If you use a tool set other than the Xilinx tools, additional naming restrictions may apply.
All components and nets have their own name space and all components and nets must have unique names within their own name space. For example, you can have a component and a net both are named “FRED,” but you cannot have two components named “FRED” or two nets named “FRED.” EPIC prevents you from entering non-unique names within a name space.

Also, the name is required.

When you add a component in EPIC, the component is assigned default programming. To figure out the default programming, you can add the component, select it, then click the Info button. The defaults are listed in the EPIC history area.

Adding a Net

To add a new net to the database use this procedure.

Select all component pins comprising the new net.

Each of the selected pins must be on a placed component (not a site), and the selected pins must not belong to any other nets.
Use the Add command in any of the following ways to add a net.
- Select Add from the Edit menu.
- Select the Add push button.
- Enter add in the EPIC Command Line dialog box.

The selected pins are joined as a net.

After using the Add command, a Net Attributes dialog box may appear for the newly created net. Whether the dialog box appears or not is controlled by the Automatic Post main window attribute. See the “Main Window Attributes” section for details. The dialog box shows the name of the new net, the number of pins and the routing status. You can edit the net attributes in this dialog box or select Cancel. See the “Net Attributes” section for details.

If the Automatic Routing Option is enabled, the new net is routed as completely as possible. If Automatic Routing is Off, ratsnest lines will connect the pins on the new net. For a description of the Automatic Routing option, see the “Automatic Routing Option” section for details.

Notes on Adding Nets

When you add nets, the name assigned to the first new net is $SIGNAL_0; subsequently added nets will be named $SIGNAL_1, $SIGNAL_2, and so forth. You can change this net name by using the Net Attributes dialog box that appears when the net is added.
Any characters special to the EPIC command interpreter must be preceded by a backslash (\) escape character when used in a net name. Special characters are quotation marks (“ or `) * ; ? # - (leading dash). The restriction only applies to commands entered at the command line or those in an EPIC command script file; the special characters may be entered in the Net Attributes dialog box without the escape character.

NOTE
If you use a tool set other than XILINX tools, additional naming restrictions may apply.
All nets and components have their own name space and all nets and components must have unique names within their own name space. For example, you can have a net and a component both of which are named “FRED,” but you cannot have two nets named “FRED” or two components named “FRED.” EPIC prevents you from entering non-unique names within a name space. Also, a name is required.

Adding Component Pins to an Existing Net

To add component pins to an existing net follow these steps.

In the editing area, select the component pins you want to add to the net.

The selected pins must be on a placed component (not a site), and the selected pins must not belong to any other net.
Select the net to which you will add the pins in one of the following ways.
- Display a list of nets in the EPIC List dialog box, then select the net name from this list.
- Select any net pin, ratsnest line, or routed segment on the desired net.
- Enter the Select command in the EPIC Command Line dialog box.
Use the Add command in any of the following ways.
- Select Add from the Edit menu.
- Select the Add push button.
- Enter add in the EPIC Command Line dialog box.
  
  The selected pins are added to the net.
  
  If the Automatic Routing option is enabled, the new net pins will be routed to the net. If Automatic Routing is Off, ratsnest lines will be drawn to the new net pins. For a description of Automatic Routing, see the “Automatic Routing Option” section.

Adding a Macro

Adding a macro to the design is described in the “Adding Macros” section of the “Working with Physical Macros” chapter.

Adding a Path

You can define a path to be used for timing analysis and timing-driven operations. When you add a path in EPIC, a Define Path constraint is applied to the design.

To add a path follow these steps.

Select the nets and components that will comprise the path.
Perform the Add command in this way.
- Select Add Path from the Edit menu.
- Enter Add Path or Add Path [path_name] in the EPIC Command Line dialog box.

The created path includes the nets and components you selected.

After using the Add Path command, a Path Attributes dialog box may appear for the newly created path. Whether the dialog box appears or not is controlled by the Automatic Post main window attribute. See the “Main Window Attributes” section for details.

The dialog box shows the name of the new path and the other path attributes. You can edit this dialog box to modify path attributes or select Cancel. See the “Path Attributes” section for details.

You can also add a path by selecting the two endpoints of the path, that is source pin and destination pins and then executing the Add Path command. When multiple paths exist for the two endpoints, EPIC defines each path.

NOTE

EPIC only enumerates the components and nets of the endpoints in the path attribute. The static timing analysis engine enumerates all intermediate components and nets.

The Define Path constraint you create when you add the path is written into the design's constraint file when the design is saved.