Adding Objects

FPGA Editor GuideChapter 3: Using the FPGA Editor

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 new nets
Add a component pin to an existing net
Add a macro to your design

You can add objects in any of the following ways.

Select Edit Add
Select Add in the User toolbar
Enter add in the Command Line toolbar

Note: Objects cannot be added if the design is in the No Logic Changes Mode.

This section contains the following topics.

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 Edit Add.

The sites become components, and these new components can be connected to other components in your design.

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

Notes on Adding Components

This section includes some additional information on adding component to your design.

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 Properties property sheet.
Any characters special to the FPGA Editor 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 FPGA Editor command script file; the special characters may be entered in the Component Properties property sheet 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 named “FRED,” but you cannot have two components named “FRED” or two nets named “FRED.” The FPGA Editor prevents you from entering non-unique names within a name space.
When you add a component in the FPGA Editor, the component is assigned default programming. To determine the default programming, add the component, select it, and click the Info button in the User toolbar. The defaults are listed in the 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 Edit Add.
- Select Add in the User toolbar.
- Enter add in the Command Line toolbar.
  
  The selected pins are joined as a net.
  
  After using the Add command, a Net Properties property sheet may appear for the newly created net. Whether the property sheet appears or not is controlled by the Automatic Post main window property. See the “Main Window Properties” section for details. The property sheet shows the name of the new net, the number of pins and the routing status. You can edit the net properties in this property sheet or select Cancel. See the “Net Properties” 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.

Notes on Adding Nets

This section includes additional information on adding nets to your design.

When you add nets, the name assigned to the first new net is $SIG_0; subsequently added nets will be named $SIG_1, $SIG_2, and so forth. You can change this net name by using the Net Properties property sheet that appears when the net is added.
Any characters special to the FPGA Editor 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 FPGA Editor command script file; the special characters may be entered in the Net Properties property sheet 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 named “FRED,” but you cannot have two nets named “FRED” or two components named “FRED.” The FPGA Editor prevents you from entering non-unique names within a name space.

Adding Component Pins to an Existing Net

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

In the Array window, 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 List window, 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 Command Line toolbar.
Select Edit Add.

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 your design is described in the “With a Different Name” section of the “Working with Physical Macros” chapter.