Research FreeRTOS Kernel For Embedded Real-time Operating System

With the development of electronic technology and introduce new embedded technology, embedded systems have been widely used in industrial, energy, transportation, information technology, defense and other fields. Thanks for the increasing of application areas and the powerful function and more intelligent, embedded software is getting much complex than ever. With the embedded real-time operating systems, the development for the embedded systems more reasonable, more efficient use of system resources, lower the development costs, shorten development cycles, simplifies the design of the system software, better meet real-time and reliability requirements of the system, it is the inevitable trend of development of embedded systems. So the research of real-time operating system has more practical application value.FreeRTOS, an open source free real-time operating system, with a small, cropping system kernel, and portability. This article was focussed on FreeRTOS operating system kernel and detail analysis of the real-time system kernel structure, task management, memory management and the communication and synchronization mechanism between tasks. Kernel structure, which is the core of the system, the task status, task scheduling, critical area processing and system time management focuses on several aspects of analysis.In order to better analyze FreeRTOS, we introduction of μC/OS-Ⅱ as a reference object, comparing to the operating system’s real-time performance and study the differences of the two operating systems the basic characteristics of the task of real-time systems, and through specific experiments switching time task preemption time, interrupt response time, semaphore acquisition and release time measuring real-time performance of the two operating systems. It using a variety of management system for memory management, but in the memory allocation time and memory fragmentation still exist certain problems. In order to improve the performance of the memory management, the analysis of several typical DSA algorithm based on introduce TLSF algorithm, analysis TLSF performance difference algorithm with the singly linked list structure, and on the basis of the algorithm is modified in the application in FreeRTOS operating system. As a general-purpose operating system, the system of transplant was the key to system research, the paper analyzes the FreeRTOS porting conditions required analysis versatility of transplantation and transplantation with STM32and S3C44B0two microcontroller platform operating system, given the key modules portable code, through a multi-tasking program carried out of the system after the transplanting to verify that the system transplant correctness.