64/128/256-bit Requester Interface - 1.0 English

Versal Adaptive SoC Integrated Block for PCI Express LogiCORE IP Product Guide (PG343)

Document ID
PG343
Release Date
2024-05-30
Version
1.0 English

The requester interface enables your Endpoint application to initiate PCIe 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 (RQ) interface is for transfer of requests (with any associated payload data) from the user application to the integrated block, and the Requester Completion (RC) interface is used by the integrated block 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 RQ interface while receiving a completion for a previous request.