Development of embedded real-time operating system based on μITRON specification for control applications

Abstract

We develop EROCA (Embedded Real-time Operating system for Control Applications). It not only follows current trend of real-time OS, but also is appropriate to control applications. It is a small to medium sized, preemptive, multi-tasking embedded real-time kernel. In order to reuse application programs and obtain commercial value, EROCA has compatibility with μITRON 3.0 specification that is designed for small-scale embedded systems and is widely used. In addition, for providing easy developing environments, various tools such as remote debugger and device drivers are supported. For fast and predictable scheduling, a multi-level queue scheduler using a bit-map is implemented. Moreover, in order to manage control applications efficiently that are mostly consisted of periodic tasks, EROCA explicitly supports not only RM but also EDF under some constraints for periodic tasks. We show the performance of EROCA through measuring several latencies such as system calls, interrupt and so forth. These latencies can be a guideline for a real-time system developer to make applications using EROCA. Some examples about RM and EDF scheduling for periodic tasks also are presented to prove its adaptability to control applications.