Connecting to the Vehicle Infotainment System

Intel’s OIP approach simplifies development and provides the low-level software to connect to communication interfaces.

By Henry Muyshondt

Intel Corp. is striving to help automakers keep pace with consumer demand and the rapid evolution of consumer-electronics products. The fundamentally different design cycles for consumer and automotive products present a challenge to their corresponding industries. To help bridge that gap, Intel is sponsoring the Open Infotainment Platforms (OIP) initiative. This initiative includes an extensive ecosystem of hardware and software vendors that offer validated, interoperable solutions. The idea is that a common hardware and software architecture can be scaled across product lines and over succeeding generations.

The OIP needs to incorporate numerous subsystems in order to fit into modern automobiles. For example, Media Oriented Systems Transport (MOST) is the de-facto standard for distributing digital audio, video, and control information in many of today’s vehicles. In contrast, Ethernet is widely used for the distribution of data. It can even be used to download large amounts of data while the car is stationary in a garage or dealer service department. In addition, Universal Serial Bus (USB) is ubiquitous in portable consumer devices. It provides a point-to-point connection and charging capabilities. Clearly, the auto industry needs solutions that bring all of these technologies together while taking advantage of each of their best features.

Bridging Design-Cycle Differences

Compared to consumer-electronics products, automobiles evolve in fundamentally different timeframes. For instance, the consumer-electronics industry moves at a much faster pace. While a typical car design will last for 20 years or more, a typical consumer product will only survive for 6 to 18 months. The major innovations in both industries do follow similar timelines, however. In the consumer world, for example, the changes from vinyl records to tapes, compact discs (CDs), and now to mass-storage devices each took 15 years or more to become widely established.

The advantage of MOST is that it provides a way to decouple the automotive-product lifecycles from consumer-product lifecycles. Essentially, the technology provides a way to build major technological advances into the automotive system—even as they evolve. At the same time, it relegates specific and rapidly changing consumer interfaces to the gateways that are attached to the vehicle backbone. The MOST standard also helps to ensure that this backbone is built to withstand the car’s harsh environmental and electromagnetic conditions. In addition, changes in the pipeline that move audio and video around are kept under the automaker’s control. The less robustrobust and rapidly changing consumer technologies can then operate while they are attached to the protected car environment.

The use of the OIP platform as proposed by Intel can take advantage of MOST to decouple the consumer and automotive worlds. Essentially, it will serve as a gateway to provide connectivity (see Figure 1). The Intel® Atom™ processor-based platform can implement the operating-system (OS) interfaces and software that have to quickly adapt to the latest consumer trends. Examples include device drivers for the latest portable media players or cellular-phone functions.

Figure 1: Media Oriented Systems Transport (MOST) will serve as a connectivity gateway for the consumer and automotive arenas.

MOST is the only high-speed-networking standard that’s used across many vehicle platforms from many different vehicle manufacturers. As of August 2008, MOST was used in 63 car models. Sixteen car manufacturers from around the world and 78 of their premier suppliers are members of the MOST Cooperation (the organization that controls the MOST standard). The Intel OIP includes support for the MOST standard through hardware and software interfaces, which are provided by SMSC and other suppliers.

Essentially, MOST is a network used to transport audio, video, and control information over a single high-speed link. Current implementations use either plastic optical fiber (POF) or twisted pair wiring—either shielded (STP) or unshielded (UTP). The MOST standard defines the physical interconnection. It also includes the high-level software interfaces that are needed to set up connections between devices as well as application programming interfaces (APIs) for higher-level functions, such as AM/FM tuners, media players, telephone interfaces, and more.

The Intel® architecture is widely used both inside and outside the car. It is an excellent platform to run the software that’s needed to implement the application and MOST NetServices layers (see Figure 2). The personal computer (PC) revolutionized the information-technology (IT) industry by having a common hardware platform and OS infrastructure on which a wide variety of applications could be developed. Now, the OIP is doing the same thing for the automotive world. Ethernet became pervasive for data communications in the PC world because it provided a simple system to move packet-based data. MOST now provides a similar automotive infrastructure for moving real-time audio, video, and control information.

Figure 2: The various layers of a MOST system architecture are depicted here.

SMSC has developed an implementation of the low-level network services defined in collaboration with the MOST Cooperation. MOST NetServices provides access to all of the data transport mechanisms on a MOST network. In addition, a MOST System Management Module handles system-related tasks that are above the MOST NetServices API. This “middleware” handles the network and system-management tasks. System designers can use NetServices to establish communications between devices without having to write all of the low-level, real-time software that’s involved in setting up a connection. The OIP platform also helps to reduce the effort needed to develop feature-rich, complex systems.

The Intelligent Network Interface Controllers (INICs) provide a standard API to the layers above them. The details of the physical interconnections are thus abstracted. As a result, the applications above the INIC don’t need to be concerned with the details of the optical or electrical connections at various speed grades.

Connecting Two Worlds

MOST also helps car companies connect to the consumer world. Basically, it allows the car’s network backbone to comply with the robustness and reliability requirements of the automotive industry. At the same time, MOST provides a pipeline for moving audio and video throughout the system. The long design cycles of a car make it difficult to adapt to the latest consumer technology. In the end, however, it’s all about presenting images to the eyes of the consumer and providing audio to his or her ears. With the standardized interfaces of MOST, car companies can maintain their backbones on their own time schedules. They only need to develop a single customized gateway device to connect to the latest trend in consumer electronics.

Currently, Ethernet and USB are two consumer technologies of interest in the car. Ethernet’s wide proliferation outside the vehicle— as well as its high bandwidth and the optimized communication of bursts or packets of information—make it a good connectivity solution to connect the automobile to outside data networks. The protocol can connect an external Ethernet-based infrastructure to a vehicle and move large amounts of diagnostic information between the two. For example, it can perform software downloads into the vehicle when the car is in a repair bay. Ethernet also can be used to move large amounts of content on and off the vehicle while in the neighborhood of an Ethernet access point.

Ethernet is an efficient data transport technology that relies on packet switching. Yet MOST provides for efficient audio and video streaming by using a circuit-switched architecture. That architecture establishes a direct channel between a source of streaming data and one or more users of that data. Ethernet was designed without deterministic delivery mechanisms. It isn’t optimized for real-time streaming applications, such as moving A/V streams to displays and amplifiers. In contrast, MOST was designed from the ground up to efficiently handle these tasks.

MOST utilizes bandwidth for continuously flowing data more efficiently than Ethernet. It eliminates addressing overhead while not relying on detecting collisions to allocate bandwidth. MOST’s synchronous nature also makes its electromagnetic susceptibility and radiation easier to manage in the harsh electrical environment of the car. The latest generation of MOST—MOST150—can even transport Ethernet packets unchanged. It provides the automotive-grade physical layer for Ethernet while carrying streaming audio and video on the same cable. The actual Ethernet connection to the outside world can be restricted to a specific location in the car. Once the data is received inside the vehicle, the automotive backbone (MOST) will be used. The combination of Ethernet and MOST allows vehicle makers to leverage the best functionality offered by each technology.

For its part, USB has become the interface of choice for many consumer-electronics devices. When a consumer brings a media player, memory card, digital camera, or cell phone into the car, its connection is likely to be over USB. Increasingly, many of these consumer devices use the USB connection as a charging port. Within the automobile, USB provides a connection to the consumer world. It can be used as a point-to-point connection to transfer the content of these devices. Carmakers also can provide a single connector that can be used to charge many different kinds of consumer devices.

Yet standard consumer USB cables introduce significant electromagnetic emissions to the vehicle. Instead of using long USB cables to a central location, MOST therefore uses USB ports that can be located where consumers will connect their devices. Content from those devices can then be sent over the MOST network backbone to the locations where it will be played back.

Another issue is that USB devices can only talk to a central host—not to each other. MOST enhances the single-host/multiple- device architecture of USB by delivering a distributed control architecture (multiple controllers and slaves). It also provides simple mechanisms for allocating the entertainment content that’s stored in various consumer products. To communicate with each other, USB devices have to go through a central controller. This aspect forces the central controller to be complex while demanding much higher processing requirements than if the individual devices could communicate with each other directly.

MOST also provides peer-to-peer connectivity. It allows for more intelligent subsystems that don’t require the whole system to be re-architected in order to add new features. If one device needs to send a video stream to another one, for example, standard MOST mechanisms can be used to set up a connection between them. The central controller doesn’t need to take data from the video source and then pass it out another port to the display. It just tells each device where the data is. Once the connection is in place, no further intervention is required.

As devices are added, they only need to understand each other and how to use the standardized MOST network services. The rest of the system doesn’t have to be modified. This is the difference between using a point-to-point connection like USB and using a full-featured network, such as MOST. Here again, the connection to the external world is through a ubiquitous consumer interface. But the transport of audio, video, and control within the vehicles is over the stable MOST infotainment backbone.

Ethernet, USB, and MOST

Automakers are developing connectivity systems that bridge the benefits of Ethernet, USB, and MOST to deliver fast and efficient data. But the rapid evolution of consumer electronics has to be reconciled with the longer automotive design cycles that are needed to ensure robustness. The convergence of data-transport technologies with audio and video-distribution requirements has resulted in a new architecture for automotive information and entertainment systems. Automakers are now developing connectivity systems that bridge the benefits of Ethernet, USB, and MOST to distribute data, control, audio, and video information. Intel’s OIP approach can simplify the development of these systems. It will provide the necessary low-level software to connect to these communication interfaces. Developers can then concentrate on their actual applications, rather than having to write custom drivers for these well-established technologies.

Henry Muyshondt is a senior director of business development for the Automotive Infotainment Systems Group of SMSC. SMSC is headquartered in Hauppauge, New York with operations in North America, Asia and Europe. Additional information is available at www.smsc.com.