High-growth era seen for embedded systems
Over the past few years, research has been focused on building desktop PCs. However, emerging technologies and social needs are moving the focus toward ambient intelligent systems that monitor, conform and respond to humans and objects, or to what we call embedded systems.
With the rapid developments in IC design, CPUs have become cost-effective. A number of consumer electronics devices have embedded CPUs, and have thus become embedded systems. According to Sandeep K. Shukla from Virginia Tech, more than 30 times as many computers are used in embedded systems as in general-purpose PCs.
Thus, there is now an apparent need to turn the focus of systems research into new directions, moving from general-purpose to application-specific systems, and from performance to reliability, availability, security, autonomy, scalability, functionality, flexibility, cost, volume, power consumption and manageability.
Embedded systems comprise software-programmable components interacting with dedicated hardware. These systems are typically application-specific, containing software, hardware and communication channels tailored for a particular task. They are part of a larger system and are often candidates for sub-SoC realizations. Today, embedded systems are used everywhere from household appliances to critical missile guidance and aerospace applications.
Designing software for embedded systems that can operate on them and make fast real-time decisions is difficult and often error-prone. Many of such systems are mission critical and hence, require high reliability guarantees. These factors make it difficult to design embedded systems in different degrees based on the application. The productivity of engineers designing such systems does not increase at the same exponential growth rate as the complexity does. Hence, there is a need for a robust design methodology that will either guarantee correct design by construction systems, or have a sound verification methodology in the design flow for assured computation, communication and satisfaction of all design constraints.
The methodology of embedded systems design encompasses various aspects. There are certain challenges that are to be considered for designing any embedded system.
Concurrent design of hardware and software: A major problem in the design process is the synchronization and integration of hardware and software design. This requires control of consistency and correctness, which is time-consuming with increasing levels of detail. Various methodologies and tools such as Polis, Cosyma and Chinook are being developed to support an integrated hardware/software co-design process.
Currently, research is aimed at providing a unified hardware and software development with design space exploration and reuse of system functions across hardware and software platforms. Research is being carried out in various universities in the United States, Europe and Asia.
M. Balakrishnan from the Indian Institute of Technology, Delhi; S.Ramesh from the Indian Institute of Technology, Bombay; Pao-Ann Hsuing from National Taiwan University; Kiyoung Choi from Seoul National University; Hiroto Yasuura from Kyushu University; Wiang Tong from Mahanakorn University of Technology, Thailand, and many others are involved in research on co-design of embedded systems.
Resource consumption evaluation of embedded software: Predicting the resources required by the embedded software is also of major importance since one can verify whether a system has accomplished its resource and real-time constraints. The most important factor to be considered for real-time embedded systems is the worst case execution time (WCET) of tasks, since it determines whether the system will meet its deadlines or not.
Research is being carried out at INRIA - the French national institute for research in computer science and control - to automatically get the application execution time on a given hardware. INRIA has developed a tool which determines the WCET for different processors and programming languages.
Enabling the use of Java for small embedded devices: The extended features of Java make it an ideal tool for embedded devices. Firstly, Java is independent of the hardware platform, and hence, portable. This helps in reducing the cost of application development in the pervasive embedded market. As Java can be run on any system, the application development can be executed on a desktop without the need for the target hardware platform. This is a strong discontinuity on the application development life cycle for embedded architectures.
Secondly, Java supports dynamic loading of applications and can significantly contribute to extending the use of wireless PDAs. However, the drawback in using Java is the need for resources to run the application. Resources include the memory, execution time and energy consumption, which are the main constraints in designing an embedded system. A team of developers at INRIA and Texas Instruments has developed a Java virtual machine and validated it on WPDA architecture. Currently, the team is developing a system to provide a high-performance Java embedded platform based on strong hardware and software cooperation.
Reliable system design: Embedded systems are used in mission-critical applications and are required to function indefinitely. This calls for reliable hardware and software. If an embedded system stops functioning due to hardware error, the system should reset itself without any human intervention.
Low-cost design: Cost is an important factor in designing an embedded system, especially for smaller applications. A few cents may cause a lasting effect in the sales and production. As miniaturization is the order of the day and the trend is to develop systems identical to SoC, it is imperative that cost is kept at the barest minimum to ensure large-scale end-user requirement.
Low-power design: One of the common system-level issues is the need for power management. Many embedded systems are powered by batteries rather than AC supply. In such cases, power consumption should be minimized to avoid draining of batteries. Hardware designers must address this issue by reducing the number of hardware components or by designing the processor to revert to standby mode when not in use.
Efficient memory usage: Most embedded systems do not have secondary storage such as a hard disk. The memory chips available on the embedded system are ROM (aids in storing the program) and RAM (aids in storing data). Depending on the functionality, the developer may determine the program and data size based on which memory requirements are important. Embedded systems use flash memory to store the program. Therefore, memory management plays a crucial role in designing an embedded system.
EDA vendors such as Synopsys, Cadence, CoWare and Mentor Graphics have come up with some design environment. Universities worldwide have also come up with various tools for embedded system design. However, these can only be used in limited ways as their applications are also limited. There is no single solution. Point tools with good methodology is the only way suitable for designing an embedded system. Research is being carried out in methodology and point tool development.
Embedded systems find applications across various industries such as aerospace/defense, manufacturing, medicine, Internet, consumer electronics and telecommunications. The market for embedded systems can be classified broadly into four segments:
Embedded processors (further divided into MCUs, MPUs and DSP);
Embedded memory such as various types of RAM, ROM and flash;
The embedded memory market is expected to grow at its highest rate in the next three years followed by embedded software, embedded processors and embedded boards.
The embedded software market is dominated by North America, accounting for a major portion of worldwide shipments in 2001, followed by Europe and the Asia-Pacific. Most embedded systems declined in 2002 but are now picking up. Due to the growing R&D in Asia, it is expected to grow at its fastest rate. On the technology side, Linux and Java are penetrating at greater speeds.
- Hema Sharma
Frost & Sullivan
|Related Articles||Editor's Choice|
|Related Articles||Editor's Choice|