1998-03-23 , S/IC-2015/24
Product News From Philips Semiconductors

The price of upgradeability on PC motherboards has been the need to open up the computer case and alter dip switch or jumper link settings. A new I²C-bus peripheral chip from Philips Semiconductors makes this risky, time-consuming process a thing of the past

Designed to support Intel's Pentium II processor chip-sets, the PCA8550 multiplexer IC from Philips Semiconductors replaces mechanical dip switches and jumper links by software-controlled configuration settings. Using this innovative single-chip solution to 'jumperless' board design, manufacturers of PC motherboards and add-in cards can now offer users a much greater level of plug-and-play compatibility - eliminating any need for users to open up their PCs in order to reconfigure the hardware.

The  PCA8550 is a 4-bit 1-of-2 multiplexer that selects between data applied to four of its input pins and the data stored in an on-chip non-volatile data register. Read/write access to the non-volatile register via the I²C-bus (System Management bus*) allows boards to be intelligently configured to suit different hardware and software requirements, either at power-up or 'on-the-fly' as programs run. Hardwired logic levels applied to the four multiplexer input pins provide the board with a set of 'fail-safe' default settings. The PCA8550's non-volatile register also contains a fifth 'latched' control bit that is available on a dedicated output pin and is guaranteed to be glitch-free during register read/write operations. The PCA8550 also features an override input that forces all the register outputs to zero, and a write-protect pin to enable/disable modification of the non-volatile register contents.

In addition to configuring motherboards for settings such as clock speed, clock multiplier and memory type, the PCA8550 can be used to provide intelligent reconfiguring of add-in cards. Manufacturers of networking, video and sound cards, which frequently require the changing of board settings to suit different hardware and software environments, will find the PCA8550 particularly useful in differentiating their cards from the competition.

Use of the PCA8550 not only benefits PC end-users. It also means that motherboard and add-in card manufacturers will be able to fully automate the testing of their boards, without the need for manual intervention or electro-mechanical devices to change jumper/dip-switch settings.

"Philips Semiconductors is proud to be the first company to provide a single-chip solution to jumperless board configuration," said Catherine de Villaneuve, general marketing manager for Philips Semiconductors' Logic Products Business Line. "As a key supplier to the PC marketplace, Philips is committed to advancing the scope of PC products and our close relationships with circuit board designers provide many opportunities to share product concepts and specifications. This co-mingling of expertise will produce many unique, high calibre products both in the near and longer-term future," she added.

Commenting on this new product introduction, Dataquest senior industry analyst Geoff Ballew said, "The PCA8550 represents a new level of integration in motherboard and peripheral board control. Just as Intel is doing, other manufacturers and value added resellers of desktop and notebook PCs will want to incorporate Philips' software mux. In addition to addressing an outstanding hardware configuration issue with a simple software solution, the PCA8550 suggests more flexibility for remote systems management."

The PCA8550, packaged in an ultra-small 16-lead TSSOP (Thin Shrink Small Outline Package) is available now in high volume. It costs in the region of US$ 0.80 in quantities of 10k or more pieces.

Philips Semiconductors, a division of Philips Electronics NV, headquartered in Eindhoven, The Netherlands, is the ninth largest semiconductor supplier in the world and the fourth largest supplier of discretes in the world. Philips Semiconductors' innovations in digital audio, video, and mobile technology position the company as a leader in the consumer, multimedia and wireless communications markets. Sales offices are located in all major markets around the world and are supported by systems labs.

*Philips Semiconductors, the largest European semiconductor manufacturer, invented the 2-wire I²C-bus in 1979 as a low-cost, easy to implement way of communicating between integrated circuits. Already widely adopted, it has come to be known in the PC industry as the System Management (SM) bus.