The Ports tab window is used to lock a user-defined port to a device package pin, to set specific Pad to Setup and Clock to Pad constraints for an individual port, to specify slew rate, and to disallow the use of I/O locations by the implementation tools.
Clicking the right mouse button in a row associated with a port name and a column associated with a constraint opens a pop-up window. Making a selection from the pop-up window opens a dialog box which is used to specify a constraint.
To open the Ports tab window, click the Ports tab on the main window.
To save information, click OK from a dialog box.
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 input/output (bidirectional). |
| Location | Signifies a pin location on the perimeter of the chip. |
| Pad to Setup | This is the time allowed for data to propagate from the input to meet the setup requirement at the synchronous element. The value here will override any value specified in the Global tab window. See “Pad to Setup” in the "Using the Constraints Editor" chapter. |
| Clock to Pad | This is the value representing the clock-to-out of the synchronous element plus the propagation time to the pad. The value here will override any value specified 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 checkmark ( ), an additional column appears in the Ports tab window: Fast/Slow. Click the box to toggle the column configuration. |
| Fast/Slow | Enables (slow) or disables (fast) the slew rate control for an individual port. See “I/O Configuration Options” in the "Using the Constraints Editor" chapter. |
| Prohibit I/O Locations | Disallows the use of I/O sites within PAR (the place and route tool) and EPIC (the graphical editor). See “Prohibit I/O Locations” in the "Using the Constraints Editor" chapter. |
