EAST 装置是一种利用磁场来约束等离子体的受控热核聚变物理实验装置。分布式定 时触发系统是EAST 装置总控系统的重要组成部分之一,用来为各子系统提供精确的触发时刻和为数据采集系统提供统一的时钟信号,该系统是以AVR系列单片机atmega128 为核心,基于NUT/OS 嵌入式实时操作系统和FPGA完成了其主要模块的基本设计,本文给出了该系统的硬件、软件的设计方案与实现方法。实验结果表明,该系统使用灵活稳定,符合预定的设计目标。 关键词:TOKAMAK;分布式;以太网;实时操作系统;FPGA Abstract: EAST Superconductive Tokamak is one kind of physical experiment installation which restrains the plasma using the magnetic field to control thermonuclear fusion. The distributed timing trigger system, which is used to provide precise trigger time to the subsystems and unification clock signals to the data acquisition system, is an important part of the central control system of the EAST Toakamak. This job is centering on atmega128, based on the embedded RTOS NUT/OS and FPGA to complete the basic design of the main system. In this paper, we have given the designing scheme and available method on its hardware and software. Experimental results imply that this system is flexible and stable, conforms to the designing goal prearranged. Keyword: TOKAMAK; Distributed; Ethernet; RTOS; FPGA