Eindhoven, Netherlands - Philips Research is preparing to spin off its internal asynchronous chip design technology in hopes of a wide uptake for a methodology that delivers low-power devices.
Known internally as Tangram, the newly renamed Handshake Technology comprises a cluster of tools, cores and design expertise that Philips Semiconductors has been using for more than 10 years, resulting in the shipment of "millions of chips" incorporating asynchronous design, said Rik van de Wiel, department manager at the Electronic Design and Tools/Tangram group of Philips Research Laboratories here.
Now Philips Research will make the Handshake Technology broadly available via a yet-to-be-formed incubator company that will offer Philips' EDA tools, design services and intellectual-property blocks to other semiconductor concerns. The move is among the latest attempts by the Dutch giant's research labs to find a broader, external market for crown jewel technology once kept for internal use only.
Thus far, asynchronous logic design has been mostly a topic of academic research, although it has been billed as "the technology of the future" for the past three decades. This novel design methodology is still far from mainstream, and some in the industry questioned last week whether IC designers accustomed to the familiar synchronous methodology could be persuaded to embrace-or even try-it any time soon.
Yet, a few semiconductor giants, including Intel Corp., are said to have quietly developed asynchronous circuits-often hidden in individual blocks-using their own internal tools. Meanwhile, commercial start-ups such as Theseus Logic Inc. (Orlando, Fla.) and Fulcrum Microsystems Inc. (Calabasas Hills, Calif.) are pursuing self-timed asynchronous logic.
Although still looking for funding, U.K.-based Self-Timed Solutions, spun out of the University of Manchester, claims to have found a way to "shorten the timing-closure phase in a design cycle" using asynchronous design technology, according to co-founder Steve Temple.
The emergence of these new competitors and the industry's need for the power-stingy circuits that asynchronous design promises are what prompted Philips Research to go public with its own technology. The company will form a self-supporting entity that will find new customers outside of Philips for the Handshake Technology. "We are clearly ahead of competitors because we've already proven our technology through our commercial products in the market," said Ad Peeters, senior scientist at Philips' Electronic Design and Tools Synthesis group. However, "If this technology stayed inside Philips, we think our competitors would eventually kill us."
Unlike most digital ICs designed today, asynchronous logic does not use clock signals to keep circuit elements working in step. Instead, the process of computation is controlled through local handshaking and handoff between adjacent blocks. The clockless asynchronous logic reportedly offers low power, low current peaks and low electromagnetic emissions-critical for applications in battery-powered handheld consumer products, automotive systems or low-cost wireless-connectivity devices.
Perhaps more important in an era of increasingly unpredictable timing, asynchronous circuits are generally self-timed: An operation starts only when all of its inputs have become valid. Thus, a block of asynchronous logic will run at the maximum speed possible for that particular die at that particular temperature, not at a predetermined-and hence conservative-clock frequency.
Philips Semiconductors has used the technique, "which allows a circuit to be active only when and where needed," for a decade in a number of ICs, said van de Wiel, including an asynchronous version of the 80C51 controller. That chip has been used as a pager baseband IC, telephony controller, game controller and smart-card IC, he said.
Peeters said the asynchronous version of the 80C51 uses 20 to 25 percent of the power required by the clocked version. Used as an alternative to a higher-speed processor in a smart card, the clockless 8-bit controller can run more-advanced applications such as crypto processing, he explained.
Handshake Technology is also "under study" for Zigbee, a low-cost, low-power, low-data-rate wireless-networking technology, van de Wiel said.
Red dots showing power dissipation are fewer on the asynchronous circuit at left than the synchronous design performing the same tasks.
But asynchronous design is neither a universal remedy for power-hungry chips nor a sweeping replacement for synchronous design, said Jim Tully, chief semiconductor analyst at Gartner Dataquest. "There are situations where a little bit of asynchronous designs may be used." But in general, "asynchronous designs can result in noise spikes or race conditions," Tully cautioned. Further, it is difficult to verify such circuits. "Proving asynchronous design can be a very nasty, time-consuming job," he said.
To push asynchronous design into commercial acceptance, the best approach may be to spotlight applications where it works best, such as ultralow-power devices, Tully said. "You need to get a toehold in the market. By proving high-volume success in such devices, you may be able to persuade the world of the need for it."
Low power, low noise
Indeed, "People who have used asynchronous design technology for a specific purpose are happy to do so, despite its drawbacks," he said. "Those who make wristwatches or hearing aids are really interested in using the technology for very low-power and very low-noise applications."
Philips' van de Wiel acknowledged that even internally, it's taken time to convince "product managers to take the risk to use our 'revolutionary' design methodology." Although Philips Research produced its first asynchronous demonstrator IC in 1987, Philips Semiconductors didn't make the asynchronous 80C51 until 1995, and Philips' first pager baseband IC didn't appear until 1997. Peeters observed that it's not all that easy for most electronic engineers to change their way of thinking about a problem. "Sometimes, they have to be hit harder on the head," he added.
Market experience has only underlined the problem. Self-Timed Solutions, spun out of the Amulet Research Group at the University of Manchester, England, has worked on short-term contracts over the past two years but is still "waiting for financing to roll in," said co-founder Temple. Experience, at least, is not an issue. Some of the company's seven co-founders collaborated with ARM Ltd. in the late 1990s to develop a clockless version of the ARM 32-bit processor, known as Amulet. Widely reported in technical conferences and the press, Amulet was heading for commercialization via Hagenuk CPS GmbH (Keil, Germany). But Hagenuk went into receivership in late 2000.
Yet Temple remains optimistic. "We are having some serious conversation with venture capitalists right now," he said.
For Philips or any other asynchronous design company to succeed, "you need to offer real good tools-not just one tool, but lots of tools, including synthesis tools and verification tools," said Dataquest's Tully. Further, the tools should be easily integrated into the mainstream EDA flow, "perhaps working very closely with EDA companies." To that end, Theseus formed a relationship with Synopsys Inc. (Mountain View, Calif.) in 2000 to jointly market some tools and to equip Synopsys design centers to use the Theseus methodology. The relationship has produced less than a breakthrough in public awareness.
Philips too plans to "partner with several parties, including EDA tool vendors," said van de Wiel. The Philips Research spinout will pursue an EDA business model by offering "complete access to our tools," he said, and will "also provide design services through technology access licenses." Under the license, "we will design a circuit for them. We can also even help them test layout." The group also plans to license IP blocks such as an asynchronous version of the 80C51.
Handshake Technology uses a special high-level design language that is "similar to a programming language like C and to a hardware-description language like behavioral Verilog," said van de Wiel. "All asynchronous details, like data encoding, arbitration and handshake protocols, are hidden from the IC designer." Declining to detail Philips' strategy further, he said, "We are agnostic regarding tool vendors, design houses and architecture suppliers."
For some applications, asynchronous design could in fact be the solution of choice in the very near future. With process variations threatening to render circuit delays all but unpredictable in 90- and 65-nanometer processes, many experts are having another look at self-timed circuitry. In addition, the proliferation of features into handheld devices, and the exploration of wearable or even implantable functions, has pushed low-power design to the edge of current art.
Additional reporting by Ron Wilson.