FPGA AI Suite: PCIe-based Design Example User Guide

ID 768977
Date 3/29/2024
Document Table of Contents

7. Design Example System Architecture for the Intel PAC with Arria® 10 GX FPGA

The Intel PAC with Arria® 10 GX FPGA design example is derived from the OpenCL BSP provided with the Intel Acceleration Stack for Intel® Xeon® CPU with FPGAs (which also includes OPAE technology).

The Intel Acceleration Stack is designed to make FPGAs usable as accelerators. On the FPGA side, the Intel Acceleration Stack splits acceleration functions into two parts:

  • The FPGA interface manager (FIM) is FPGA hardware that contains the FPGA interface unit (FIU) and external interfaces for functions like memory access and networking. The FIM is locked and cannot be changed. The FIM is sometimes referred to as BBS, blue bits, or blue bitstream.
  • The accelerator function (AF) is a compiled accelerator image implemented in FPGA logic that accelerates an application. AFs are compiled from accelerator functional units (AFUs). An AFU and associated AFs are sometimes referred to as GBS, green bits, or green bitstream. An FPGA device can be reprogrammed while leaving the FIM in place.

The FIM handles external interfaces to the host, to which it is connected via PCIe. On the host side, a driver stack communicates with the AFU via the FIM. This is referred to as OPAE (Open Programmable Acceleration Engine). OPAE talks to the AFU with the CCI-P (core cache interface) protocol that provides an abstraction over PCIe protocol.