Quartus® Prime Pro Edition User Guide: Platform Designer

ID 683609
Date 2/11/2025
Public
Document Table of Contents

5.10.6.3. Enabling Concurrent Subordinate Access

When using AXI interfaces, concurrent subordinate access enables multiple subordinate access from one manager (1xM support). This access ensures that you can send commands to various subordinates in parallel, and that those responses process with better efficiency than processing responses serially.

For concurrent subordinate access, Platform Designer places the re-ordering buffer (ROB) on the manager side because of the addresses and IDs to multiple subordinates that require buffering.

Turning on No Repeated IDs Between Subordinates indicates that the manager does not send the same ID to multiple subordinates. Enabling No Repeated IDs Between Subordinates, along with concurrent subordinate access, means that a read command with different IDs received by subordinates can potentially send out-of-order response back to the manager.

Turning off No Repeated IDs Between Subordinates ensures that subordinates send in-order response back to the manager.

Note: If you turn on No Repeated IDs Between Subordinates but still use the same ID for different subordinates, the interconnect does not prevent this configuration. However, this configuration can cause system failure if both subordinates receive the same IDs but the subordinate that receives the command later responds first.

To enable concurrent subordinate access in AXI Bridge Intel FPGA IP, follow these steps:

  1. In the Platform Designer System Contents tab, double-click the AXI Bridge IP. The IP parameter editor appears.
  2. Under Master Side Interface, turn on the Enable Concurrent Subordinate Access parameter.
  3. To prevent duplicate IDs for subordinates, turn on the No Repeated IDs Between Subordinates parameter.
    Figure 245. AXI Bridge IP Parameter Editor


To enable these same parameters for other IP in the system, follow these steps:

  1. In the Platform Designer System Contents tab, right-click the IP, and then click Edit Component Instantiation.
  2. In the Signals & Interfaces tab, select the AXI manager.
  3. Specify a value of 1 for the enableConcurrentSubordinateAccess parameter.
  4. Specify a value of 1 for the noRepeatedIdsBetweenSubordinates parameter.
  5. Click the Finish button.
    Figure 246. Specifying Concurrent Subordinate Access