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Volume 37 (Mar 16, 2005)
Supporting the development of automotive and other control systems: The V850 Integrated Development Environment in conjunction with MATLAB®
Advancements in the computerization of automotive control systems
Advances are being made in the computerization of automobiles in nearly every conceivable unit. In particular, microcontrollers are being used to perform complex control in engines, air bags, brakes, and other equipment out of concern for safety and the environment as well as to make vehicles more comfortable for drivers and passengers (Figure 1). Take, for example, engines. In response to the continuing escalation of global environmental problems, actions are being taken in nations across the world to strengthen emission regulations for toxic substances contained in exhaust emitted from vehicles, since these emissions are one of the causes behind air pollution. In line with this, microcontrollers can be used in engines to increase fuel efficiency and control the parts to prevent the discharge of unnecessary emissions. In the case of air bags, microcontrollers can be used to control the timing of air bag release to coordinate with the brakes and steering wheel during a collision so as to reduce the risk to human life.
Operations like these are primarily controlled via software. There has thus been a tremendous increase in the number of microcontroller software programs available, and finding a way to increase the efficiency of software development has become a challenge.
MATLAB®: Fast becoming the mainstream in control system development
A development style referred to as the "V process" is commonly used in the automotive industry (Figure 2). The name is derived from the fact that the flow of steps—from specification consideration to final product completion—can be likened to the shape of the letter "V." In this process, a developer must over and over again verify the presence or absence of defects in the item being designed, readjusting the design if any defects are found and then once again verifying the presence or absence of defects in the product.
"Model-based development," in which a simulation model (e.g., virtual engine) is used to finalize software specifications, is now commonly used during specification design (prototyping) prior to verification. Rather than immediately verifying the prototype software on actual equipment, an environment (model) is first created in which the actual control of an engine can be simulated and verification of the virtual operation performed. In this way, logical mistakes in the specifications, mistakes in microcontroller control register configuration and other design errors can be detected in advance, without having to use actual equipment. Moreover, since exception-handling routines can be verified in advance, the burden faced during verification of actual equipment can be reduced and software development performed more efficiently.
MATLAB® and Simulink® are primarily used as simulation tools for the creation of virtual environments employed for this process. MATLAB® and Simulink® are manufactured by The MathWorks, Inc. and now widely adopted for use in dynamic system simulations, since system models can easily be constructed in a graphical environment created using block diagrams. These tools are fast becoming the mainstream for development of automotive control systems.
The V850 Integrated Development Environment in cooperation with MATLAB®
Aiming to support the creation of advanced control systems including those used for model-based development, NEC Electronics has launched its V850 Series of 32-bit RISC microcontrollers that excel at real-time control. We are also responding to our customers' desire for fewer burdens during software development by providing various of solutions incorporating both the V850 Series development environment and the MATLAB® model-based development environment. One such example is the incorporation of Applilet, a device driver generator that improves efficiency at the prototyping stage (Figure 3). Development costs can be reduced by using the Real-Time Workshop® Embedded Coder (RTW-EC), a MATLAB®/Simulink® automatic code generator, together with Applilet. In addition, since device drivers as well as other original user files can be designated together with automatically generated code on the RTW-EC settings screen in this environment, automatic code generation processing can be started automatically with the V850 Integrated Development Environment. Moreover, with just the touch of a button, the program's build and debugging functions can be used, production costs lowered and the development period shortened.
NEC Electronics also provides evaluation boards and emulators for use during the unit test stage in the verification process, which is strengthened to support MATLAB®/Simulink®. Furthermore, to improve design efficiency at each stage of the "V process," NEC Electronics is currently constructing a V850 Series-based development environment incorporating a variety of tools developed by its partner companies (Figure 4).
To provide a complete lineup of control system solutions, including those used in the automotive industry, NEC Electronics plans to continue incorporating MATLAB® in its creation of development environments aimed at meeting the diverse needs of its customers.
• MATLAB®, Simulink® and Real-Time Workshop® Embedded Coder are registered trademarks of The MathWorks.
Volume 38
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