仕様の状態遷移図記述による組込みソフトウェア開発手法

Abstract

Concerning the development of firmware, important problems include reducing the number of processes and the periods for testing and validation while preserving quality and reducing the overall time taken for product development. To solve these problems, one effective approach is to reduce the number of design iterations by ensuring adequate drawing up, review and validation of product specifications at an early stage of the design. One method of doing this is to write formal descriptions of the specifications for review and validation. An approach frequently adopted is to use Harel Statecharts as suggested in the OMT (Object Modeling Technique) method. However, design methods that address directly the conditions in Harel diagrams have yet to be established. The article proposes a design method that addresses the control conditions affecting basic product operations. It consists of describing the conditions that affect the entire product as a combination of basic operations, and to describe controls with reference to these basic operations. Furthermore, we propose that by using simulations of the Statecharts so created, practical actuators should be directly controlled to create a validation environment for the specifications.We have applied the proposed method to the development of control software to be built into prototype air-conditioning equipment. The preparation of the Statecharts for the prototype equipment demonstrated the effectiveness of this approach.