The Research And Design Of RTOS Based On Cortex M3 Processor

With the development of science and technology, more and more embedded products began to fitting into people's lives. The requirements of multiple Tasks make the technology of embedded real-time operating system becomes the focus of embedded research. Now, nearly all well-known embedded real-time operating system on market are developed by foreign companies. The foreign real-time systems usually expensive, character also have difficult to satisfy the public demand, and technical support are much inconvenience for regional language reasons. So the study of embedded real-time system has an important significance. Based on the study of current embedded real-time operating system kernel in domestic and on abroad, this thesis combining the characteristics of Cortex M3 processor, designed a fully functional real-time operating system kernel CoOS. It has the following features:●Specially designed for Cortex-M3 series micro controller●Supports preemptive priority and round-robin scheduling mode●Interrupt latency is 0●highly Scalable●Semaphore, Mutex, Flag, Mailbox and Queue for communication & synchronisation●Stack overflow detection optionThis design began design the entire system from the core task scheduling, including bottom implementation, scheduling module, and doing unit testing. After test pass, then gradually added other modules into the whole system, such as time management, synchronization and communication mechanism and storage management, and did unit testing and the integration testing. After testing and modification, the system can steady running. Task scheduling and interrupt of the system is normal, the system achieved the design goals.This thesis start with the processor architecture classification, first introduced the characteristics of Cortex M3 processor and the present situation of some RTOS at domestic and on abroad, and giving the design goal of CoOS. Secondly introduced some components of Cortex M3 processor which closely related to RTOS, including registers, instruction sets, work patterns, Privilege level, stack Settings, nested vector interrupt controller, and so on, provided a theoretical basis for the design and implementation of the CoOS. Then introduced the real-time kernel design and implementation in detail, including:task management, time management, synchronization and communication mechanism, storage management, and gave the testing methods of each module and the whole system. And analyzed the major characteristics of CoOS, including real-time, security, portability, and scalablility, gave performance comparison between CoOS and other mainstream OS. At last, gave a multitasking application design example on the chip of STM32 based on CoOS. Through this example, this thesis introduced the configuration and the usage of CoOS.