Agilex™ 7 F-Series and I-Series FPGA Memory Subsystem IP User Guide

ID 789389
Date 7/15/2024
Public
Document Table of Contents

8.2.5.6. Propagation of Changes Across IPs within the Memory Subsystem IP

Some IPs within the Memory Subsystem IP have parameters that in case of a change, may enable more options or alter the width of a signal connected to another internal IP.

Changing this type of IP parameter in the Platform Designer does not immediately propagate to dependent IPs. To propagate such changes, follow these steps:

  1. Change the required IP parameters within the Memory Subsystem IP in the Platform Designer window.
  2. Save the system by clicking File > Save. This action triggers subsystem validation; a pop-up window appears, indicating progress.
  3. The system automatically reloads in the Platform Designer view. You can verify that all the changes have propagated.

An example of this behavior would be to change the DQ Width on the external memory interface (EMIF) IP. Because the Memory Subsystem IP always adheres an MSA to each EMIF IP, the width of the AXI4 interface on the exported MSA must have an adequate size to send all the required bits to comply with the specified Burst Length of the EMIF controller.

For example, the default DQ width of instantiated EMIF by the Memory Subsystem is 32 bits, this is the reason for the dependent MSA to have, by default, an AXI write data width of 256 bits (32 bits x BL8). If you change the EMIF DQ width to 16 bits, the related MSA AXI data width parameter does not immediately allow you to select a 128 bit write data width. To see this option listed in the parameter of the MSA, you must follow the steps described above.