Research On The Technology Of PCI Express Used In Embedded Platforms

With the development of information technology, the size of digital resources is increased, and the scale of data exchanging between digital devices is enlarging. The increasing size of data requires data transmission interfaces with higher bandwidth. To meet this requirement, PCI Express is put forward, and is used widely in PC. PCIe is still rarely used in embedded platforms, but it should appear in embedded fields more often with the enhancement of the performance of embedded systems. This paper researched on the application of PCIe in embedded platforms.Firstly, the application of PCIe in FPGA and embedded Power PC processor communication system is illustrated, and a kind of feasible plan is designed and implemented. Further more, based on this plan, the application of PCIe in multi-embedded Power PC processors communication system is discussed, and a feasible plan is designed and implemented. Both of the two plans are put into practice. In FPGA and embedded Power PC processor communication system, embedded Power PC processor acts as RC device, while FPGA acts as EP device, a PCIe link is formed between them. And in multi-embedded Power PC processors communication system, one Power PC processor acts as RC device, and the others act as EP devices. The PCIe link is expanded by the switch chip, and a single to multiple PCIe link is formed. The software of the two systems are based on the embedded Linux operating system. The Linux applications initialize and control the PCIe links through the PCIe device drivers. The work on the two embedded platforms includes follows.1. In FPGA and embedded Power PC processor communication system, a PCIe EP device is implemented based on the PCIe IP core inside the Xilinx's Virtex6 family FPGA, and forms a PCIe link with the MPC8377 processor which acts as RC device. FPGA and Power PC can communicate throught the embedded Linux application and the EP device driver running on MPC8377.2. In multi-embedded PowerPC processors communication system, the communication between multiple MPC8377 s is implemented. One processor acts as RC in the upstream of the switch, while the others act as EPs in the downstream of the switch. The embedded application and driver running on RC work together with the application running on EPs, and they can perform the communication between RC and EPs.The running test results of these two kinds of embedded platforms are provided, which prove that they completely meet the designed requirements.