News Item Dated: 27 December 2002
From: Computerworld  (12/23/02) Vol. 36, No. 52, P. 29; Anthes, Gary H.

The reliability of the synchronous circuits or "clocks" common in most computers is more difficult to maintain as chips increase in size and complexity, and their heat output and power consumption rise with each new chip generation. To find a solution, manufacturers are testing clockless processors, some of which are totally asynchronous while others integrate local synchronous elements with asynchronous networks. Asynchronous circuits have faster performance levels than circuits with clocks, while their lower heat output and power consumption make them a good component for mobile devices. The forthcoming UltraSPARC IIIi processor from Sun Microsystems features asynchronous circuits that transfer data between memory modules and memory controllers; Sun senior staff engineer Jo Ebergen explains that the benefits of this architecture include greater reliability, simple design, potentially faster speed, and ease of modification.

Meanwhile, Self-Timed Solutions has developed prototype "self-timed interconnects" that company co-founder Steve Furber calls asynchronous "network fabrics" where processors, memory blocks, or other synchronous or clockless "clients" that run at different frequencies can easily be plugged in. However, the design infrastructure and expertise of asynchronous devices are nowhere near those of synchronous devices. Chris Myers of the University of Utah says that there will be a gradual industry shift toward microprocessor designs that are "globally asynchronous, locally synchronous," in which synchronous circuits with different clock speeds interact via an asynchronous "fabric."

Interested? For further reading, check out this link: http://www.computerworld.com/hardwaretopics/hardware/story/0,10801,76931,00.html