Kernel Analysis And Porting Of RTOS μc/os-Ⅱ

Embedded system is a kind of special system that can meet application system's compositive and strict demand on function, reliability, cost, size and power consumption. It is based on computer technology, takes applying as centre, based on computer technology, its software and hardware can be reduced. Generally it is composed of microprocessor, relevant supporting hardware, embedded operation system and upper level application software system. Therefore, it realizes control, surveillance and management of other equipments.μc/os-Ⅱis a embedded real-time operating systems (RTOS) ,with its excellent reliability and real-time performance, it has been widely used in communications, military, aviation, aerospace and other areas with high-technology and high-demand of real-time performance..μc/os-Ⅱis a real-time operating system kernel, only contains task scheduling, task management, time management, memory management and inter-task communication and synchronization, and other basic functions, This paper mainly analyses tasks management and interrupt mechanism.Task management ofμc/os-Ⅱkernel is realized by task control block and task ready table. The ready table needs different task should have different priority, even if these two tasks are of equal importance. Therefore it leads several problems on task switch and priority inversion. In this situation, this paper make some improvement on task scheduling, it schedules tasks in the set with same priority, instead of in task ready table, it determines the highest-priority tasks set firstly, then schedules tasks in this set with time slice method.The problem of priority revertion is very common in real-tijme kernel, this paper makes some correction on the function concerning about mutex signal, thereby solves this problem.LPC2000 series is a microcontrollers based on the 16-/32-bit ARM7TDMI-STMCPU that supports real-time simulation and tracking,This paper portsμc/os-Ⅱto this processor, lists detail code, and support a multi-task program, it also test the system after porting, the simulation experiment show the correctness of this porting.Finally to show how to program on embedded real-time operating system, this paper develops a digital oscillograph system.