USB - the car-consumer connection
(This article originally appeared on EE Times Europe's Automotive site.)
In consumer electronics as well as in most computing environments, USB today is the most popular interface technology. Also in automotive environments, USB is about to conquer the pole position among competitive technologies. At chip level, the supporting infrastructure is already available.
Dr. Matthias Stümpfle, Head of System Architecture and Platforms at Daimler AG says: "USB is the most ubiquitous consumer interface today. Its widespread use makes it an attractive way to connect the consumer's digital world with the sophisticated entertainment systems of the car. However, to put such an interface in a car requires much more than performing some stress tests on a commercial IC. Automotive applications demand high quality and reliability levels that require component designers to have the automobile in mind when they first begin creating their ICs.
Furthermore, the whole supply chain needs to be tuned to quickly respond to any issues and to identify the root cause of any problems that are found along the way. USB, along with a robust and reliable MOST information and entertainment backbone, can help decouple the different development cycles of the automotive and consumer industries, while allowing car makers to quickly deliver new functions available in the consumer environment."
USB is indeed the interface of choice for many of today's consumer electronics products. Everything from cameras, to telephones and media players, as well as portable navigation devices uses USB. Even devices with wireless interfaces, such as a Bluetooth phone, need to be connected to charge their batteries. USB provides the perfect interface: it is in widespread use and has a very well defined connector that makes it easy for both carmakers and device makers to use. USB Hubs
USB uses a master-slave hierarchy. There is one USB host that connects to multiple USB devices. Many of the microcontrollers used in today's vehicles provide at least a single USB port. However, more ports are needed to connect devices that are both internal to the vehicle or that a consumer can bring into the car.
USB hubs provide multiple downstream ports that connect to a single port on the microcontroller. SMSC's USB82514 USB 2.0 hub, for example, provides up to 4 additional USB ports. Connecting to telephones, iPods and other media players are obvious applications as car makers seek to become part of their customers' digital world.
The widespread use of USB has resulted in embedded applications also using the interface inside a component, where it is not accessible to the user. Devices like Bluetooth radios are available with USB interfaces. Mass storage is available in the form of USB drives that are both inexpensive and more reliable than their rotating media counterparts. Hubs allow the connection of both embedded and external consumer devices.