Analysis And Implementation Of IEEE1588Protocol Based On Embedded Linux

With the digital construction of the substation, there is a trend using application of distributed systems. Each system communicate over the network, and the demand of high precision, low cost, easy to be setting clock synchronization system is increasing. The current network time synchronization technologies, such as SNTP (Simple Network Time Protocol) are difficult to meet the synchronization accuracy requirements of the power system. And IEEE1588protocol can effectively solve the problem of high precision time synchronization. Without increasing the network load, the clocks of whole system can accurate synchronization. With the auxiliary of hardware circuit, the maximum accuracy could reach the nanosecond level, which can fulfill the best time synchronization requirements of the substation.Based on the detailed analysis of the IEEE1588protocol, this article introduce the architecture of PTP system, basic PTP devices, principle of clock synchronization, best master clock algorithm, state machine of protocol engine, and timestamp of event messages. These are the basic knowledge of how to design and implement the time synchronization system.This paper presents the solution of IEEE1588protocol, and implements the main control module, the message management module, and the best master clock module. This article also elaborates the hardware design composed of ARM9+FPGA+MAC+PHY; ARM9microprocessor is in charge of the operation of IEEE1588protocol. FPGA is used to detect messages on the MII interface, which is between MAC and PHY, generate timestamp and fulfill time calibration. The software development of IEEE1588time synchronization system is under the platform of embedded Linux. On the basis of detailed study of embedded Linux system, this paper develops the FPGA and DM9000device drivers, transplants the whole system to the ARM920Tplatform. Finally, it tests the design and analyzes the experimental result.