Ports Tab Window

When you create a constraint from the Ports tab window, the constraint is applied to a specified port. Any constraint created from the Ports tab window overrides a contending constraint created from the Global tab window.

Constraints created from the Ports tab window are used to do the following.

• Lock a user-defined port to a device package pin
  
  
• Set specific Pad to Setup and Clock to Pad constraints for an individual port
  
  
• Specify output slew rate
  
  
• Prohibit the use of I/O locations by the implementation tools.
  
  
• Pullup, pulldown, or keep the input level on a pad net with a tri-state buffer.
  
  
• Specify an I/O Standard (Virtex devices only)
  
  
• Specify a drive strength (in mA) for output ports
  
  
• Group pads
  
  

To open the Ports tab window, click the Ports tab on the main window.

To close the window, click the Global or Advanced tab.

Figure 5.3 Ports Tab Window

Field	Description
Port Name	Identifies the port as defined by the user.
Port Direction	Identifies the direction of the port as input, output, or bidir (input/output).
Location	Specifies a pin location on the package.
Pad to Setup	Specifies a value representing the clock delay and the time allowed for data to propagate from the input to meet the setup requirement at the synchronous element plus the clock delay. The value here will override any value specified for the selected port in the Global tab window. See “Pad to Setup” in the "Using the Constraints Editor" chapter.
Clock to Pad	Specifies a value representing the clock-to-out of the synchronous element plus the propagation time to the pad and the clock delay. The value here will override any value specified for the selected port in the Global tab window. See “Clock to Pad” in the "Using the Constraints Editor" chapter.
I/O Configuration Options	When this box displays a check mark (), a number of columns (depending on the target device) are added to the grid in the Ports tab window, such as FAST/SLOW in the above figure. Click the box to toggle the column configuration. See the “I/O Configuration Options” section in the Using the Constraints Editor chapter.
Prohibit I/O Locations	Disallows the use of I/O sites within PAR (Place and Route) and FPGA Editor. See “Prohibit I/O Locations” in the "Using the Constraints Editor" chapter.