Implementation will occur around some type of display device

The convergence of C3 (computer, communications, and consumer) electronics has been discussed for many years. While only an idea in the past, the convergence appears to be accelerating rapidly. Home users can obtain Internet access via traditional telephone or cable TV companies. Internet data can be viewed via personal computers or Web TV systems. The recent popularity of sub-$1,000 personal computers indicates that a PC in every home could become reality. Convergence centers on the personal computer or high-end television because of display and data entry capability.

A Graphical User Interface (GUI) or On-Screen Display (OSD) provides users better control of increasingly complex systems. Connectivity standards such as Universal Serial Bus (USB), IEEE 1394, IrBus, and CEBus are moving from paperwork inside a committee to end-user equipment installed in the field. Networks serve as an isolation mechanism allowing the individual system developers freedom to innovate with minimal effects on the other components. Each connectivity standard addresses a different class of applications having similar characteristics.

To be successful in the age of convergence, electronics OEMs must design with technologies that offer maximum flexibility and time to market. As these protocols evolve, OEMs using field programmable technology in microcontrollers and gate arrays, for example, can quickly adapt to changing market conditions. By isolating groups of similar devices, these connectivity protocols can be implemented in a simple manner without excess device overhead. Some of the leading protocols impacting embedded design in convergence applications are discussed below.
While the battle for control of the converging markets continues between personal computers or Web-connected televisions, the key enabling connectivity standards are moving forward. Most connectivity standards for PCs address the major complaint from users–opening the system and configuring hardware such as interrupt signals or direct memory access (DMA) requests. Many times devices must share signals and there is a potential for conflicts. The plug-and-play system developed for the PCI local bus allows the system software to detect and configure new hardware components. The overall connectivity goal for the PC would allow the user to add any new device without opening the system.

Many personal computers now have the support for USB connections. The USB addresses low-to-medium speed applications for serial type devices with a fully connected protocol (error detection and recovery). The low-speed devices operate at 1.5 megabits/second supporting asynchronous type traffic from interactive devices like keyboards, pointing devices, game peripherals, and monitor configuration. High-speed devices operate at 12Mb/sec that target devices such as telephony, audio, and compressed video. Using the isochronous mode, a high-speed device can obtain the entire channel bandwidth with guaranteed low latency for real-time data streams.

Up to 127 devices can be connected in a tiered star topology using expansion hubs. Devices can obtain power directly from the USB (bus powered) or via AC line (self powered). Hot insertion provides a large USB benefit allowing device attachment or removal to/from the bus while powered. Dynamic attach/detach allows a second game peripheral to be added to a system for another player without the power down and reboot sequence. Expansion hubs notify the host of the connection change and the device identifies itself to the system software for configuration. In addition, systems using all the USB connections could easily remove a device temporarily while a new device connection is required.

IEEE 1394 will begin appearing in personal computers this year. Operating at up to 400Mb/sec. the bus allows support for digital video from cameras or VCRs. Both asynchronous and isochronous transfers are supported, allowing system buffering to be minimized. IEEE 1394 supports the hot swapping (insertion/deletion under operation) of devices with automation configuration. Unlike USB, IEEE 1394 provides a peer-to-peer communication path allowing direct data transfers between devices without a host (PC or Web TV) attachment. IEEE 1394 allows mixing of devices at 100-, 200-, and 400Mb/sec. allowing new nodes into an existing network without upgrading all other devices. For the long-term, the IEEE 1394 addresses scalability up to 1 gigabit/sec.

Device Bay provides a standard mechanical form factor and electrical interface for adding peripheral devices into the system without opening the chassis. Three form factors are defined with specifications for size, power dissipation, and thermal characteristics. Each Device Bay unit communicates with the host via either USB or IEEE 1394 attachments. Device Bay applications include CD-ROM, DVD players or smart card readers for media or security enhancements to systems without opening the chassis.

Device Bay units support the Advanced Configuration and Power Interface (ACPI) mechanism already found in PCs today. Hot (system under power) insertion/deletion of Device Bay’s units with automatic configuration via plug-and-play allows easy customization by the user.

IrBus is an emerging standard for infrared bi-directional command and control communications for wireless devices. Possible users include pointing devices, gamepads, or remote controls interfacing to PCs. A single system can have up to eight devices attached simultaneously operating up to 75Kb/sec. For entertainment applications the system guarantees a 13-millisecond response time for time critical communication. IrBus supports communication up to eight meters distance between host and remote devices. Since infrared transmission has minimal governmental regulation the IrBus could achieve a worldwide standard.

Finally, CEBus is standard for home automation addressing low-cost networks in residential environments. A major factor for success is the ability to offer many cost alternatives (scalability) to allow the addition of network control to consumer appliances selling for $20 or less as well as to durable items such as air conditioners, washing machines, and dryers. The CEBus standard (EIA-600) was developed by the Electronic Industries Association (EIA) Consumer Electronics Group as a foundation for intelligent control within a residential environment.