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Due to the spread of cheap microcomputers based on recent progress in semiconductor technology, control panels that have been realized with such things as traditional mechanical-type switches have become computerized, and they have been replaced with graphic screens, such as touch panels and liquid crystal displays. For large-scale systems, such as plant controls and building monitoring in factories, it's a matter of course, but many equipment types in our surroundings, such as home appliances and office automation equipment, photocopiers, facsimile machines, ticket terminals, audio visual equipment, and telephones, possess graphic screens for computer control, and they have realized programmable human machine interfaces (HMIs). By graphicalizing and computerizing various types of switches that have complex functions, turning on and off switches in accordance with control settings, and making the same hardware compatible with various applications become possible.
What has been created in order to develop control software for these types of graphical electronic devices is BTRON (Business TRON). BTRON is a real-time, multitask, multi-window, general-purpose operating system, and in addition to applications such as word processing and Internet terminal, it is optimally suited also for the implementation of HMIs in control devices and handheld equipment. Factory plant control systems, building environment control systems, etc., using BTRON are already in operation. Moreover, using a palmtop-type portable BTRON machine, there is in operation even an insurance terminal system that introduces a complex menu of commercial life insurance products and calculates on the spot an estimate and conditions matched to a client.
There are various merits to using BTRON as a computer for embedded control use, but first, as number one, is the fact that high real-time performance can be obtained. In the latest version of BTRON, we have built in the ITRON real-time operating system as the core of its inner parts, and we have attained real-time performance that is not at all inferior to ITRON. Of course, because it's a real-time operating system, simultaneously monitoring multiple switches and sensors is also easy.
Moreover, middleware, such as display primitives and parts managers, are included in BTRON, and, by using these, we can realize a user interface (GUI - Graphical User Interface) in which a graphic screen is used. Furthermore, even if we include everything from the main body of the operating system up to the GUI functions, the amount of memory required is kept below 4 to 6 megabytes.
Well then, what greatly makes efficient software development in a case where we will utilize BTRON in this manner for embedded control purposes is the "MicroScript" visual language that is explained in this book.
There are several merits to it, but first is that because it employs a compiler-interpreter method using intermediate code, development and debugging is easy, and, furthermore, high execution performance can be obtained.
Another great merit of MicroScript is that we can develop the visual parts that we will display on the screen separately from the programming language portion using BTRON's figure editor software. For example, in a case where we will display the picture of a virtual switch on the screen, it is not necessary to input with coordinate values the shape and size of the switch, rather it is possible to freely design it using the abundant functions of the figure editor software. To go further, it becomes possible to make independent the HMI screen design work that demands artistic sense and the programming work that demands technical sense, to divide those between the respective persons in charge, and thus carry out distributed development. Moreover, moving pictures drawn with BTRON on the screen and effecting animation, and creating presentation systems in which screens are displayed one after the other in the manner of slides are also easy.
Of course, the real-time multitask functions of BTRON can also be utilized as is from MicroScript, and thus it is possible to realize even complicated processing in which we simultaneously monitor multiple switches.
Furthermore, outside of embedded control purposes, MicroScript can be utilized across a wide range in the development of such things as demonstration programs, animation, games, education software, and on-line magazines.
While BTRON possesses unique merits, such as a hypertext function based on the real object virtual/object model, and compatibility with multiple languages, I would like to learn that there is still another application field for it through your combining these together with MicroScript. I look forward to discovering further interesting application examples for MicroScript based on your simple ideas and schemes after you have read through this book.
September 1997
Ken Sakamura
Project Leader
The above contents of BTRON MicroScript Reference Manual were translated and loaded onto this Web page with the permission of Personal Media Corporation.
Copyright (c) 1997 Personal Media Corporation
Copyright (c) 2009 Sakamura Laboratory, University Museum, University of Tokyo