Abstract: A mixed kernel architecture of embedded operating system which can support time triggered and event triggered tasks at the same time is designed. The mixed architecture is based on the architecture of μC/OS-II operating system and its interfaces are consistent with OSEK/VDX specification so it is portable. A static, periodic, preemptive scheduling policy for mixed tasks is proposed in the architecture. The scheduling policy supports task switching both at interrupt level and task level and the EDF（Earliest Deadline First） algorithm is used for tasks retrieving. Compared to OSEKtime OS which support task switching only at interrupt level and FIFO（First In First Out） algorithm for tasks retrieving, the proposed policy can improve resource utilization and ensure real-time tasks execution as far as possible. The results of experiment and analysis show that the mixed kernel architecture of embedded operating system is convenient for porting and the scheduling policy proposed for mixed tasks is feasible and effective.

Key words: embedded operating systems, time triggered/event triggered, tasks scheduling, Open System and the Corresponding Interfaces for Automotive Electronics/Vehicle Distributed Executive（OSEK/VDX） standard, μC/OS-II

摘要： 针对当前嵌入式系统中时间触发与事件触发混合任务的特点，以μC/OS-II操作系统架构为基础，设计了一种能够同时支持时间触发与事件触发的混合操作系统内核架构。该架构符合OSEK/VDX标准，具有良好的可移植性。针对混合任务调度问题，提出了一种静态周期性可抢占式混合任务调度策略，该策略同时支持中断级与任务级的任务切换，并采用EDF（最早截止时间优先）算法对被抢占的时间触发任务进行恢复，相比OSEKtime OS只能在中断级进行任务切换以及FIFO（先进先出）恢复算法，能够提高系统资源利用率，并最大限度保证任务实时性。实验分析结果表明，所设计的混合操作系统架构移植方便，所提出的混合任务调度策略可行有效，调度过程具有良好的可预测性。

关键词: 嵌入式操作系统, 时间/事件触发, 任务调度, 汽车电子类开发系统和对应接口标准/汽车分布式执行标准（OSEK/VDX）, &mu, C/OS-II