Miscellaneous Tips for Using the Schematic Capture Tool

This section describes various tips for creating schematic designs.

Color-coded Symbols

Symbols are color-coded to represent their type.

• Schematic user macros - blue
  
  
• Primitives and empty symbols - red
  
  
• HDL, State Editor, and netlist macros - purple
  
  
• State Editor macros - purple
  
  
• Library macros - black
  
  

These color codes are the default values. If you wish to change the defaults, select View Preferences Colors from Schematic Capture.

Using the Hierarchy Connector

Only use the Hierarchy Connector when specifying pins for a schematic macro. Never use hierarchy connectors on top-level schematic sheets.

Using Input and Output Buffers

Xilinx schematics require that you use input and output buffers between input and output ports. The following figures illustrate incorrect and correct input and output port design.

Figure 4.3 Incorrect Port Design (Without Buffers)

Figure 4.4 Correct Port Design (With Buffers)

Schematic Tabs

Tabs on a schematic sheet facilitate navigation between schematic sheets. The following example shows the tabs that display after opening the schematics for the “lock” project.

Note the LOCK1 and LOCK2 tabs in the lower left corner of the figure. Clicking on the LOCK2 tab navigates to the LOCK2 schematic sheet. For every new schematic sheet added to the design, a new tab displays.

In addition, if you use Hierarchy Push to display the schematic for a component or macro, a new tab also displays in the lower left corner.

Simulate Current Macro

In Foundation 1.5, you can simulate a macro in a schematic design:

1. Select the macro in your design.
   
   
2. Click Hierarchy Push and then double click the design.
   
   
3. After the design displays, select Options Simulate Current Macro. When the Logic Simulator window displays, you can perform a functional simulation of the macro. Refer to the “Functional Simulation” chapter for details.