Outbound Access Using Regions

A maximum of 32 outbound regions can be active at the same time. Each region has registers that control its operation.

Figure 1. AXI Outbound Access Block Diagram

The outbound access is a two-step process:

  1. Region Setup—Before accessing the region registers, you program them using the APB interface.
  2. Region Access—You access the region registers through the outbound AXI interface.
Table 1. Outbound Registers for 1 Region
Registers Description
Outbound AXI to PCIe address translation registers Performs address translation from the AXI address to the PCIe address.
Outbound PCIe descriptor registers Holds the TLP information to be sent outbound.
AXI region base address registers Holds the AXI region base address and the region size of the corresponding region. The PCIe Controller uses this register set to decode the region by matching it to the incoming AXI address.