Research And Implementation Of Task Scheduling Mechanism Based On Embedded System

Embedded systems are given computer system for special application, but common embedded system have weakness which kernel is too redundancy and task scheduling processing are too complex. In contrast, the development of intelligent instruments demand small kernel, high reliability and low power requirements to embedded system. So urgently need that alter the existing order execution hyper-cycle with task scheduling is needed to meet resources management system requirements.In this paper, we firstly analyzes the three most common task scheduling algorithm, whose are based on priority, based on proportional sharing and the task scheduling algorithm, based on time respectively. And then analysis the characteristics of each scheduling algorithm and summarize different algorithms for system applicability. Through research the scheduling strategy of task scheduling, in view of some embedded system have no operating system, has the coupling of strong, task scheduling processing are too complex shortcomings, we proposed a method of secondary structure based on priority task scheduling, which can be used to implement the mix much task scheduling. For operating system task management inflexibility, we established task control blocks which have two-way link table structure, so that making task management convenience. According to system with same priority task scheduling complex problems, we establish with priority task two-way link table and adding to control block lists to realize same priority task's scheduling strategy of first in first out. For highest priority task uncertainty in searching for scheduling processing, established data structure of status table for storing higher-priority task priority, so that greatly improving the task searching speed, Finally we realize the memory management mechanism, shorten system memory allocations of searching time and improve the stability of the system, so effectively suppress the embedded system memory pieces.We verify realized task scheduling mechanism Using EPA control system, according the control system's need, making function block configuration, setting parameters according to function blocks, record each function blocks'time stamp of task running. Experimental results show that the programmable logic controller equipment can correctly run accor-ding to the function blocks task scheduling strategy so that realizing the system control functions.