You can view and change a number of attributes for many EPIC objects. You can display attributes for these items.
Some of the attributes you view and change represent constraints applied to the design. If you change these attributes in EPIC, the resulting constraints changes are written into your design's constraints file when you save your design.
To post a dialog box showing object attributes, use the Post Attr command. The command posts the necessary dialog boxes to list the properties of the selected object(s). You can then use the dialog boxes to change the object's properties.
The Post Attr command can be performed in one of the following ways.
If you want to post attributes for more than one object, select all of the objects first. The dialog boxes will appear for all of the selected components when you use the Post Attr command. The dialog boxes appear in the order in which the objects were selected.
You can modify certain properties shown in the dialog box. The rest of the fields in the dialog box are read-only fields; they cannot be modified. To activate changes, click OK, which activates the changes and closes the dialog box or Apply, which activates the changes and keeps the dialog box in view.
Two other EPIC commands are related to object attributes. The Getattr command displays attributes for selected objects in the history window. The Info button on the push button panel also displays attributes.
The Setattr command changes selected attributes for selected objects. The Getattr command provides the same information as posting an attribute box, while the Setattr command makes the same modifications as using the dialog box. You can view or change a specific attribute without displaying and using a dialog box. Both Getattr and Setattr are described in the “Command Line Syntax” chapter.
The Getattr, Setattr, and Post Attr commands are all affected by the Automatic Deselect option. When Automatic Deselect is enabled, selected objects are automatically deselected after the command is executed. If the Automatic Deselect option is disabled, the object remains selected.
The following sections describe how to display and change object attributes using dialog boxes.
To view or change attributes for the main EPIC window, invoke the Post Attr command in one of the following ways.
The Main Window Attributes dialog box appears.
Figure 3.7 Main Window Attributes Dialog Box |  |
| Design Name | Name of the design in the EPIC window. |
| EPIC Version | Indicates the revision level of the EPIC software. |
| Speed | Displays appropriate speeds. Determines the speed (toggle rate) of the part you are editing. |
| Edit Mode | Displays these options: Read Only, Read Write, or No Logic Changes. The default is No Logic Changes for an existing design and Read Write for a new design. Determines what modifications can be made to the design. The Edit Modes are described in the “Main Window Attributes” section. |
| Automatic Deselect | Determines whether the Automatic Deselect option is enabled or disabled. When the option is enabled, selected objects are deselected after a Delay, DRC, EditBlock, Hilite, Setattr, Getattr, or Post Attr command is performed. When the option is disabled, selected objects remain selected after one of these commands is performed. The default is Automatic Deselect Option enabled. |
| Automatic Hilite | Determines whether objects are automatically highlighted. When the option is enabled, delay paths are highlighted after a Delay command, and the net being edited is highlighted after manual routing. When the option is disabled, no automatic highlighting occurs. By default, the option is disabled. |
| Automatic Post | Determines whether a dialog attributes box appears when a new object is created. When the option is enabled, a component, net, path, macro, or external pin attribute dialog box appears after an Add command, and after a route or autoroute operation in which a new net is created. When the option is disabled, no dialog box appears. By default, the option is enabled. |
| Stub Trimming Option | Determines whether the Stub Trimming Option is enabled or disabled. When the option is enabled, only the portion of a routing resource that lies directly on the path between two routed pins displays in the editing area. A portion of a long line or a pinwire are examples. When option is disabled, the entire routing resource taken up by the route, such as an entire long line, displays in the editing area. The default is Stub Trimming Option enabled. |
| Automatic Routing | Determines whether the Automatic Routing Option is enabled or disabled. When enabled, the system automatically routes any unrouted nets created as a result of an editing action, such as placing components, creating new nets, swapping components. The default is Automatic Routing Option enabled. |
| Enhanced Manual Routing | Determines whether the autorouter is called if specified manual route connections cannot be made. When the option is enabled, the Route command attempts to make a connection between user-specified resources. If the connection fails, it autoroutes between those resources. When the option is disabled, no call to the autorouter occurs. By default, the option is enabled. |
| Delay-Based Routing | Determines the type of autorouting done by the autoroute command on selected objects. When enabled, the autorouter takes delay values into account. When disabled, cost-based autorouting is done. Delay-based autorouting takes longer, but can result in better results, especially on a crowded design. By default, the option is enabled. This option has no effect on an Autoroute All operation. |
| Show Constraints | Calls up a dialog box displaying all the global constraints that apply to the design. The dialog box is shown in the following figure. |
If you select Show Constraints from the Main Window Attributes dialog box, the following dialog box appears.
Figure 3.8 Global Constraints Dialog Box | |
| Lock Routing | Applies a lock routing constraint to all partially or fully routed nets in the design. The lock routing constraint specifies that the current routing cannot be changed or unrouted. |
| Penalize Tilde | Applies a Penalize Tilde constraint to the design. This constraint penalizes those delays that are reported as only approximate, signified with a tilde (~) in delay reports by the percentage specified in this field. |
| All Paths Maxdelay | Applies a Maxdelay Allpaths constraint to the design. This constraint specifies the maximum delay for all paths in the design. |
| All Nets Maxdelay | Applies a Maxdelay Allnets constraint to the design. This constraint specifies the maximum delay for all nets in the design. |
| Period | Applies a period constraint to the design, which specifies the clock period for all clock nets in the design. Either a Period or a Frequency should be entered in this dialog box, but not both. |
| HIGH/LOW | Specifies whether the first pulse of the duty cycle is High or Low. The field immediately to the right of this field specifies the duration of the first pulse of the duty cycle. |
| Maxskew | Applies a Maxskew constraint to the design, which specifies the maximum allowable clock skew for all clock nets in the design. |
The Component Attributes dialog box appears when you select a component and perform the Post Attr command.
Figure 3.9 Component Attributes Dialog Box | |
| Name | Name of the component. There is no character limit. |
| Type | Type of component, for example, CLB, TBUF, PULLUP. |
| Designator | Indicates the reference designator of the site in which the component is placed or indicates “unplaced.” |
| Show Logic Strings | Displays the Component Logic Attributes dialog box, which shows the internal programming of the component. Does not apply to components that cannot be programmed, such as XC3000 tristate buffers. |
| Show Constraints | Displays the Component Constraints dialog box, which displays the constraints that are applied to the component. |
When the selected component is a programmable logic block, you can select Show Logic Strings in the dialog box to display a Component Logic Attributes dialog box. This dialog box displays the internal programming of the CLB. However, you cannot edit any fields. Use the logic block editor to modify a CLB. Dialog boxes may differ between device families.
Figure 3.10 Component Logic Attributes Dialog Box (CLB) | |
| Base | Base mode of the CLB |
| Config | State of the CLB, including multiplexers and other logic elements |
| Name | Name of the CLB. |
| F= | Determines the Boolean equation for the F output of the CLB's combinatorial logic section. |
| G= | Determines the Boolean equation for the G output of the CLB's combinatorial logic section. |
Select Show Constraints from the Component Attributes dialog box to display the Component Constraints dialog box.
Figure 3.11 Constraints Dialog Box (Logic Components) | |
| Name | Component name. There is no character limit. |
| Lock | Locks that the component to its current location. |
| Locate | Indicates whether the automatic placement range is an absolute requirement (HARD) or preferable (SOFT). |
| Level | Sets up a priority for the autoplacer to resolve constraint conflicts. |
| Range | Specifies the location of the site or range of sites for the autoplacer. |
| Block | A timing constraint to block the enumeration of all timing paths that go through this component. |
| TSid | Assigns a timing period or frequency to a timing specification. |
The Pin Attributes dialog box appears when you select a site or component pin and perform the Post Attr command. You cannot edit any fields. If the pin you select is a macro external pin, a different dialog box appears. See the .
Figure 3.12 Pin Attributes Dialog Box | |
| Name | Name of the pin. |
| Component Name | Name of the component containing the pin. This scrollable, non-modifiable text field has no character limit. |
| Site Name | Site in which the component containing the pin is placed. |
| Type | Indicates whether the pin is an INPUT, OUTPUT, TRISTATE, or CLOCK pin. |
| Net Name | Name of the net to which this pin belongs. If the pin is unused, NO SIGNAL appears. This scrollable, non-modifiable text field holds up to 50 characters. |
| Show Constraints | Displays a Pin Constraints dialog box, which displays the constraints that have been applied to the pin. |
The Net Attributes dialog box appears when you select a net and perform the Post Attr command. A partially or fully routed net can be selected by pressing the Shift key while selecting any routed segment on the net. An unrouted net can be selected by selecting the ratsnest, by selecting its name from a list in the EPIC List dialog box, or by using the Select command in the EPIC Command Line dialog box.
Figure 3.13 Net Attributes Dialog Box | |
| Name | Net name |
| Route Status | Indicates whether the net is UNROUTED, PARTIALLY ROUTED, or FULLY ROUTED. For VCC and Ground nets, the status is preceded with either PWR or GND. |
| Number of Pins | Indicates how many net pins this net contains. |
| Show Pin List | Displays a Pin List dialog box, which describes the net pins comprising the net and is described following. |
| Show Constraints | Displays a Net Constraints dialog box, which displays the constraints that have been applied to the net. |
When you select Show Pin List, the Pin List dialog box appears. This dialog box describes each net pin on the net.
Figure 3.14 Pin List Dialog Box | |
You cannot edit any of the information in the Pin List dialog box. The Pin List will only display information for net pins on placed components. No pin names or other information will appear for net pins on unplaced components.
| Pin Name | Name of the pin, in the form, reference_designator.pin_name. |
| Pin Type | Indicates whether the pin is an INPUT, OUTPUT, TRISTATE, or CLOCK pin. |
| Delay | Delay time from the net source to this pin. This field is blank if the pin is unrouted. For VCC and ground pins, the delay is indicated with a dash. |
If you select Show Constraints in the Net Attributes dialog box, the Net Constraints dialog box appears.
Figure 3.15 Net Constraints Dialog Box | |
| Name | Net name - this field is non-modifiable, scrollable, and may contain an unlimited number of characters. |
| Lock Status | Indicates whether the net is locked or unlocked. If a net is locked, also indicates whether the net is locked due to a lock net or lock routing constraints. A locked net cannot be unrouted or deleted. Pins and components connected to the net cannot be unplaced, swapped, or deleted. |
| Lock Net | Locks the net by applying a Lock Net constraint. The net cannot be unrouted or deleted. |
| Block | Applies a Block Net constraint to the net, which prevents timing analysis on the named net and on all paths through the named net. |
| Prioritize | When specified, applies a Prioritize Net constraint to the net. The constraint assigns a weighted importance (0-100) to the named net (with 0 as least important and 100 as most important). A net with a priority of 3 or less is not considered critical. |
| Period | When specified, applies a Period constraint to the net, which assigns a clock period for all sequential output and input pins clocked by the net. Enter a period or a frequency in this field, but not both. |
| HIGH/LOW | Specifies whether the first pulse of the duty cycle will be High or Low. The field immediately to the right of this field specifies the duration of the first pulse of the duty cycle. |
| TSid | Assigns a timing period or frequency to a timing specification. |
| Maxdelay | When specified, applies a Maxdelay constraint to the net, which specifies a maximum total delay for the driver-to-load connections on the net. |
| Maxskew | When filled in, applies a maxskew constraint to the clock net. The maxskew constraint specifies the difference between the minimum and maximum load delays on the net. |
The Site Attributes dialog box appears when you select a site and perform the Post Attr command.
Figure 3.16 Site Attributes Dialog Box | |
| Name | Site name |
| Prohibit | Applies a Prohibit Site constraint to the site, which specifies that no component can be placed it. You can exclude a site to reserve it for future use |
The Wire Attributes dialog box, shown in the following figure, appears when you select a pinwire, a local line, or a long line. The dialog box appears whether you select a routed or an unrouted portion of a wire.
Figure 3.17 Wire Attributes Dialog Box | |
| Type | Indicates whether the selected wire is a PINWIRE, LOCAL line, LONG line, SWITCH BOX line, or PROGRAMMED SWITCH. |
| Net Name | This scrollable, non-modifiable field has no character limit. If the wire is used, it indicates the net routed along this wire. If the wire is unused, NO NET appears. |
Macro attributes are described in the “Viewing and Changing Macro Attributes” section of the “Working with Physical Macros” chapter.
The Path Attributes dialog box, shown in the following figure, appears when you select a path and perform the Post Attr command.
Figure 3.18 Path Attributes Dialog Box | |
| Name | Name of the selected path |
| Elements | Names of the components and nets comprising the path. Each line has no character limit |
| Block | Indicates that a Block Path constraint is applied to the path, which blocks timing analysis on the path |
| TSid | Assigns a timing period or frequency to a timing specification |
| Maxdelay | Applies a Maxdelay constraint to the path, which specifies the maximum delay for the path |
| Priority | Lists the priority and the locked attribute for the Q1 net |
An EPIC layer contains all of one type of object, for example, all long lines in the device or all components in the design database. To see a list of all available layers, select Layers in the EPIC List dialog box.
The Layer Attributes dialog box appears when you select any EPIC layer and perform the Post Attr command. Layers cannot be selected in the editing area; they must be selected from the layers list in the EPIC List dialog box or by using the Select command in the EPIC Command Line dialog box.
Figure 3.19 Layer Attributes Dialog Box | |
| Name | Type of object in the layer |
| Type | Indicates what type of layer: BLOCK, WIRE, NODE, or OTHER |
| Color | Determines the color of objects in the layer. If you select this field, an option menu appears, from which you select one of fifteen colors |
