Improvement Of CM3-OS Embedded Operating System

With the growing complexity of embedded systems and the increasing competition in the market, the traditional embedded applications face dual challenges in the hardware platform upgrade and design software updates. To the hardware side, the high performance 32-bit microcontroller has become the mainstream of the market, it provide so abundant hardware resources that make it no longer become a bottleneck; To the software side, due to the poor flexibility, the long development cycle, and the high maintenance cost, the original design patterns foreground/background have been replaced by the embedded operating systems. But the current embedded operating system on the market is mostly designed for the 8/16 bit platform, and has a lot of underutilized resources on the 32-bit platform, and the internal operating mechanism is too complicated to understand. For these two points, Based on the study of current embedded operating system kernel in domestic and on abroad, this thesis designs an embedded operating system kernel CM3-OS for the Cortex M3 processor.This thesis start with an overview of Cortex-M3, and focuses on those components of Cortex-M3 processor which closely related to operating system, including the core registers, processor modes, privilege level, stacks, exception handling mechanism, memory model and the Cortex Microcontroller Software Interface Standard, laying the foundation for the design and implementation of CM3-OS.Secondly with Cortex-M3 processor features, introduce the CM3-OS kernel design and implementation in detail, including task management, synchronization and communication, resource management and memory management modules. CM3-OS uses the priority-based preemptive and cooperative task scheduling strategy and the unity of event-driven mechanism, the synchronization between tasks is completed by the event flag, the communication between tasks is completed by mailbox. And depending on the resource access restrictions, CM3-OS provides different mutual exclusion mechanism. In addition, the system’s memory utilization is optimized to make maximum use of memory, while enhancing the robustness of the system.In order to meet the needs of engineering, the thesis introduce the embedded graphical user interface library ST-GUI-lib to the system which provided by the STM Company, and depend on the understanding of the internal operational mechanism, realize the graphics driver, graphical display and human-computer interaction.Finally, to demonstrate the configuration of the CM3-OS and how to use them, with the intelligent light controller and the parking guidance light controller for the prototype, built two experimental systems based on CM3-OS operating system. And through these experimental systems, verify the stability and reliability of CM3-OS.