The embedded industry was born with the invention of microcontrollers/microprocessors and since then it has evolved into various forms, from primarily being designed for machine control applications to various other new verticals with the convergence of data communications.
Various classes of embedded systems such as media systems for homes, portable players, smartphones, embedded medical devices and sensors, automotive embedded systems have surrounded us and with continued convergence of data communications and computing functions within these devices, embedded systems are transforming themselves into really complex systems, thus creating newer opportunities and challenges to develop and market more powerful, energy-efficient processors, peripherals and other accessories.
An embedded system is more than electronics as most people perceive it. It has electronics – both digital and analogue, special purpose sensors and actuators, software, mechanical items etc., and with design challenges of space, weight, speed, cost and power consumption. Its important characteristics are low-power, real-time responsiveness, low thermal dissipation, predictable, small physical form factor/footprint, low radiation/emission, ruggedness in design and impervious to external radiations etc.
To achieve key requirements, generally, embedded systems are restricted to limited resources in terms of computing, memory, display size etc. With the continued convergence of other technologies, a lot more functionalities are being pushed into embedded devices that were once part of traditional computing platforms. This further adds a major “decision challenge” for architects and product managers on the selection of processors, operating systems, standards of usage etc., as demands on functionality increase with time to market decreases.
Automotive Embedded System
With drive across the world to improve on emission controls and bring in efficiency in usage of fossil fuels, the automotive segment is challenged by various factors and embedded systems are the ways and means of achieving multiple objectives in this segment taking it from infotainment systems, engine control unit, Car-area-network, fuel management, safety systems all need to be embedded to be in it.
Traffic management and prediction systems are being developed for large cities across the world today and the critical systems that have to support this are M2M or V2V communication networks that, form adhoc networks, seamlessly gather information from multiple sources, fuse and make decisions that not only help the car users but also city traffic managers.
The real-time management of this is possible only by having embedded computing and communication systems that are part of the vehicle and the network. The usage of vehicle tracking and fleet tracking has already been beneficial for the operators by reducing their OPEX and downtime which has enhanced customer satisfaction.
This apart, media-oriented systems transport (MOST) is one of the technologies being deployed by OEMs for multimedia and infotainment networking. This technology is designed to provide an efficient and cost-effective fabric to transmit audio, video, data and control information between devices attached even to the harsh environment of an automobile.
MOST (Media Oriented Systems Transport) is a high-speed multimedia network technology optimized by the automotive industry. It can be used for applications inside or outside the car. The serial MOST bus uses a daisy-chain topology or ring topology and synchronous data communication to transport audio, video, voice and data signals via plastic optical fiber (POF) (MOST25, MOST150) or electrical conductor (MOST50, MOST150) physical layers.
MOST technology is used in almost every car brand worldwide, including Audi, BMW, General Motors, Hyundai, Jaguar,Lancia, Land Rover, Mercedes-Benz, Porsche, Toyota, Volkswagen, SAAB, SKODA, SEAT and Volvo. SMSC and MOST are registered trademarks of Standard Microsystems Corporation (“SMSC”), now owned by Microchip Technology.
The first multimedia installation based on MOST bus and protocol was introduced in the year 2001. In the same year, the MOST bus was applied in the next ten vehicle models. In the year 2013, MOST Cooperation consortium could report MOST introduction into 140 vehicle models including new models i.e. Audi A3 and Mercedes class S. MOST bus and protocol have been present in popular medium segment vehicles e.g. Volkswagen Golf and Opel Insignia as well as the models: Rolls Royce Ghost, Phantom and Wraith. The functioning of the majority of wire communication buses in motor vehicles is based on a linear bus topology. Therefore MOST bus is a unique solution because it is based on ring topology (Fig. 1). The application of fiber optic solutions is another specific feature. Communication via cable connections is possible after the transceivers replacement.
MOST bus operation is typical for ring topology. The data block received from the preceding node is used as an information and commands source. The block received from the preceding node is regenerated and forwarded. Turned off devices transmit the optical signal without its analysis. The data transfer is finished when the block is received by its sender. The ring contains some special nodes responsible for the ring management i.e. commands generation based on user activity and for the ring synchronization (Fig. 1b). MOST protocol and bus are dedicated to multimedia networks which are sometimes called Infotainment networks. High throughput levels are required for data stream in such networks. Despite MOST150 standard functioning for several years, this fact has been not mentioned in many publications. Most often the graphical presentations inform about the throughput of about 25 Mbps (Fig. 2)which is underestimated by three times. The throughput of 150 Mbps will be probably exceeded soon. The manufacturers of Plastic Optical Fibers (POF) indicate the throughputs of 500 Mbps along the section of 20 m or 170 Mbps along the section of 115 m. The transceiving equipment is prepared for operation with a throughput of 5 Gbps. The current throughput is sufficient to use MOST as an element in the network supporting images received from the security camera or the games network.