9.6.4 Making I/O Assignments

To make I/O assignment for the Memory Interface instance in the design:

  1. Select the Memory Interface type from the drop-down menu.
  2. From the Ports tab in the Design Tree View, drag the Memory Interface instance and let the mouse hover over one of the Edge_Anchor locations available for the Memory Interface type. A tooltip reports whether it is a legal or illegal location for the Interface instance.
  3. Drop the Interface instance into a legal Edge_Anchor location.
    4. Note: DRC rules are enforced. Drag-and-drop I/O placement that violates the DRC rules are reported in the Log window. For Memory Interface, the DRC checks the Data Width and the Data Rate compliance*. If the specific location cannot accommodate the Data Width or the Data Rate of the Memory interface, no I/O assignment is made. An error is reported in the Log Window with a message that explains why the assignment is not accepted. In the following figure, the DRC error message reports that the ddr3 instance requires 64 ports, but the SOUTH_SE location can accommodate only 58 pins.
    Note: *Data Rate compliance will be enforced in a later release.
    Figure 9-8. DRC Checks in Log Window
  4. Check that no DRC error messages are reported in the Log window and the I/O assignments are accepted (see the following figure). The Lock icon in the Ports tab indicates that the I/O assignment is accepted and locked.
    Figure 9-9. Memory Interface Assignments Accepted