Research And Realization Of RTOS In Underwater Acoustic Communication System

With the increasing of ocean exploitation, the techniques of underwater acoustic (UWA) communications have rapidly developed, which play an important role in the fields of ocean exploration, disasters forecasting, underwater remote controlling and ocean information collecting, etc. A full UWA communication system includes several modules, such as coding and decoding of signal source and channel, signal modulation and demodulation, signal transmitting and receiving, etc., so it must be supported by complicated software and hardware systems. Real-time operating system (RTOS) is effective in managing various hardware modules and it supplies APIs, which can simplify the designing of software and decrease the time of development. This thesis analyzes the principles of several embedded RTOSs and studies the realization of a RTOS. An operating system (called UWAC-RTOS) has been developed for UWA communication system, which selects SPCE061A as the target processor.The kernel of UWAC-RTOS has functions of task managing, task scheduling, interrupt managing, etc. Task management takes charge of creating, deleting, suspending and resuming task. Task scheduler adopts the strategy of fixed-priority preemption to improve the real-time performance, and it can schedule 16 tasks at one time. Interrupt management is used to deal with the asynchronous events.For the purpose of minimizing the spending of system resources, UWAC-RTOS was written by assemble language. The APIs of UWAC-RTOS can be called by both assemble and C language. Its kernel is reconfigurable and reducible, which makes the applications in different occasions possible.Several tests were designed to compare the performances of UWAC-RTOS andμC/OS-II. Tested items include consumption of memory, time between task switching and the longest time of interrupt forbiddance. The results prove that UWAC-RTOS has a smaller kernel, a better real-time performance, and runs stably.