1024-Bit Requester Interface - 3.4 English

Versal Adaptive SoC CPM Mode for PCI Express Product Guide (PG346)

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3.4 English

This section describes the operation of the user-side Requester interface associated with the 1024-bit AXI4-Stream Interface.

The Requester interface enables a user Endpoint application to initiate PCI transactions as a bus master across the PCIe link to the host memory. For Root Complexes, this interface is also used to initiate I/O and configuration requests. This interface can also be used by both Endpoints and Root Complexes to send messages on the PCIe link. The transactions on this interface are similar to those on the completer interface, except that the roles of the core and the user application are reversed. Posted transactions are performed as single indivisible operations and Non-Posted transactions as split transactions.

The requester interface consists of two separate interfaces, one for data transfer in each direction. Each interface is based on the AXI4-Stream protocol, and its width can be configured as 64, 128 or 256 bits. The requester request interface is used for transfer of requests (with any associated payload data) from the user application to the core, and the requester completion interface is used by the core to deliver Completions received from the link (for Non-Posted requests) to the user application. The two interfaces operate independently, that is, the user application can transfer new requests over the requester request interface while receiving a completion for a previous request.
Note: All signals in the waves are not appended with pcie0 or pcie1 ports, but apply to both pcie0* and pcie1* ports.