IJIREEICE - Electrical, Electronics, Instrumentation and Control

Abstract

Real-time operating system (RTOS) is a very useful tool for developing the application on embedded boards with least software development effort. Though number of RTOS products are available in the market, µC/OS-II is a freeware with minimum facility and more popular among the hobbyist, researchers and small embedded system developers. The µC/OS-II supports preemptive scheduling which is not efficient with respect to processor utilization. As a result, this may lead to missing deadline of the task assigned and hence may cause system failure. In this paper, a Rate Monotonic scheduling (RM), which is a better scheduling method when compared to preemptive technique, is implemented on µC/OS-II and its operation in terms of task execution and processor utilization are discussed. This paper presents the RM Analysis (RMA) on µC/OS-II with two different types of hardware: 1) Low end microcontroller i.e., 8051 based system and 2) High end system based on ARM9 is used. For the demonstration of RM Analysis, two tasks, namely, 1) Advanced encryption standard (AES) and 2) Text message display and graphic display are implemented. The software tools Keil IDE, SDCC compiler and Phillips Flash Magic are used for implementation of tasks on 8051 embedded development board. The ARM developers Suite v1.2 and DNW are used for implementation of tasks on ARM9 development board. In addition to the above said tasks, additional tasks like Real time clock interface, graphical LCD interface and UART interface for communication with computer are also implemented. The scaled-version of µC/OS-II with multiple tasks uses 4 kB of flash and 512 bytes of RAM in 8051 board. The entire MUCOS RTOS in ARM9 with multiple tasks uses 29.23 kB of flash and 596.36 kB of RAM. The results obtained indicate optimum utilization of processor with RMA scheduler for realizing low cost software for developing the application on embedded boards with least software development effort.