Embedded Systems November 2000 Vol13_12

Issue link:

Contents of this Issue


Page 81 of 189

If all of the technology pieces come together and home networking is widely accepted by customers, the consequences could be far reaching. As with the other standards that are defining APis, the OSGi must also define a et of services and interfaces for specific vertical markets. The er- vices curre ntly being addressed include Energy Management Service, Securi ty Service, Health Care Service, Home Automa tion Se rvice, and Entertainment Services tl1at provide pay-as-you-play advanced Interne t- based entertainment services. HAVi HAVi i tl1e Home Audio/ Video inter- operabili ty specification. HAVi being sponsored by Sony, Hitachi, Grundig, Philips, and othe rs. As Figure 11 shows, HAVi was designed to ride on top of IEEE1394-no surprise considering its consumer electronics heri tage. HAVi defines a set of protocols/ APis that include device abstrac- tion/ device con trol models, an addressing scheme/ lookup service, an open execution environment, Plug-n- Play capabili ty (through 1394) , and manageme nt of isochronous data streams. The HAVi specification contains a number of distinct software elements tl1at each provide a certain functional- ity. The oftware elements that are needed for interoperabili ty between HAVi devices are the Messaging System, th e Registry, the Event Manager, the Resource Manager, tl1e Stream Manager, and the DCM Manager. Software elements called device control modules (DCMs) provide con- trol over device-specific functionality such as a VCR or a camera. DCMs are loaded onto HAVi compliant devices and a re used to control othe r devices-in other words, a download- able user interface. HAVi does not define data formats; it relies on a stream manager to move data from one device to another, but the data format could be anything. The pecifi- cation does allow for the creation of true transcoder devices that can turn one format into the other. HAVi defin es four levels of specifi- cation compliance. They are defin ed as Full AV (FAV), Interoperable AV (IAV), Base AV (BAV), and Legacy AV (LAV) . The compliance levels are shown in Table 3. The only difference between FAV and IAV devices is the support for J ava by the device. This allows devices to be fully HAVi func- tional without incurring the cost and overhead associated with a JVM. Conclusion Imaging and multimedia applications, such as multi-user games, video- phones, remote Windows terminals, information tablets and digital video will burden all but the highest-speed networks. A single channel of HDTV will consume 19Mbps by itself. Aside from the data transfer issues, other items must be addre sed. Home net- working must be truly Plug and Play. It can be no more complicated than plugging a modem into a phone line and dialing up an ISP. The entire pro- tocol stack must be re-examined and addressed in order to provide true interoperability among t the various types of devices. If all of the technology pieces come together and home networking is widely accepted by customers, the con- sequences could be far reaching. This technology, along with high speed Inte rnet access will truly drive the compute r I communicati o ns/ co n- sumer electronics convergence. Voice over IP, Internet radi o, news, securi ty, and a pletlwra of imaging applications will all be enhanced. Imaging applica- tions stand to benefit the most from all of tl1is new bandwidtl1-the Internet is all about sharing information, and images are one of the best methods of conveying information. 80 NOVEMBER 2ooo Embedded Systems Programming One of the more fa r reaching implications will be the role oftl1e PC in thi s scenario. The PC will most likely play a less visible role in the ne t- worked home. It will probably not di s- appear e ntirely, but be relegated to more of a server/ gateway role. The combined computing power of all of the Internet imaging and informa- tion appliances in a home will far out- strip that of even the most powe rful PC. esp John Canosa is chief scientist at Questm. He has over 20 years of experience in the embedded industry, including analog and digital hardware and software design. Prior to joining Qu. estm, he was manager of the Electronics Design group f or the University of Rochester's Laboratory for Laser Energetics, a large inertial confine- ment fusion laser system. John has a BS in electrical engineering from Clarkson University and an MS in electrical engi- neering frorn Rochester Institute of Technology. His jcanosa@questra. corn e-rnail address is References and resources "Fundamentals of Firewire", John Canosa, Embedded Systems Programming Magazine, June 1999 Websites: www. homerf. org www. www. www) www. jetsend. hp. com www. homeapi. org www. upnp. org www. www. cablelabs. com www.adsl. org www. telecomresearch. com

Articles in this issue

Archives of this issue

view archives of EETimes - Embedded Systems November 2000 Vol13_12