mobile | classic  
Dataweek Electronics & Communications Technology Magazine


Electronics Buyers' Guide

Electronics Manufacturing & Production Handbook 2015


Time for the clockless computer chip
26 February 2003, Computer/Embedded Technology

Time is literally running out for the conventional range of computers that we now use. Since the advent of fast and complex systems in the 1960s, all hardware design has been based on the principle of the clock.

This is in the guise of a microelectronic crystal that emits rapid pulses of electricity to synchronise the flow of data. So much so, that such a crystal can be best described as the heart of the Pentium processor and other similar chips.

Despite this apparent success story, progress has now overtaken the ubiquitous clock and turned it into the computer's Achilles heel. The fatal flaw is that computer systems are now so complex that clocks are imposing limitations on performance.

But help is at hand. In response to this massive problem, a group of UK scientists have developed a new generation of hardware blocks and design tools based on the ideas originally introduced in the 1950s. Their asynchronous, or clock-free systems, hold out the exciting promise of extra speed, safety, security and miniaturisation.

Future face: the layout of a ‘clockless’ microchip. Chips such as these hold out the exciting promise of extra speed, safety and security along with further miniaturisation.
Future face: the layout of a ‘clockless’ microchip. Chips such as these hold out the exciting promise of extra speed, safety and security along with further miniaturisation.

"The new designs already work well in the laboratory and are only awaiting the development of software tools so that they can be produced commercially," says Professor Alex Yakovlev, who leads the team of researchers in the Department of Computing Science at Newcastle University, northeast England.

They presented two groundbreaking papers at an international symposium on advanced research in asynchronous circuits and systems at Manchester, England. One paper explains the latest techniques the team has developed for synthesising asynchronous systems; the other relates to measuring time intervals and what is known as metastability, a problem which may be the cause of the death knell for conventional computers.

The root of the problem here is that electrical pulses, travelling at the speed of light, are not fast enough to keep accurate time as they visit tens of millions of transistors on a single chip. The result is that errors begin to occur in data.

This metastability phenomenon is a fundamental and insoluble problem which is causing increasing difficulty for designers who have to balance the demand for speed and complexity of systems with the need for reliability.

"In binary terms, incoming data has a metastable state in which it is neither true nor false," says Professor Yakovlev. "A resulting system failure would be inconvenient to a PC user and could result in a disaster in an industry where reliability is critical, such as aviation."

Asynchronous systems rely on a protocol of data transmission and acknowledgement which is not regulated by time. This can happen locally in a computer or globally between computers. Data is exchanged by means of a 'handshake', or agreement on the mutually acceptable protocol.

Computer clocks generate heat as well as high frequencies, because they consume large amounts of power. To abolish them would allow portable devices to run on less power, enabling further miniaturisation.

There is an added security bonus with this fresh approach. Hackers would also be troubled by asynchronous systems, because the irregular pattern of data transmission allows the information to be encrypted far more effectively than at present.

Professor Yakovlev believes that the clock-based system is nearing the end of its useful life, with designers facing increasing difficulties as systems become more complex.

"One of the problems is that all graduates entering the industry are immediately taught to design systems with clocks," he adds. "It will be difficult to persuade them to change their ways. We have shown that asynchronous systems work, but we need to develop simple tools for commercial design and testing purposes. In my opinion, this is the last piece of the jigsaw," he added.

One of the barriers is that designing asynchronous systems requires the use of a new hardware design language involving concepts of concurrency, partial order, causality, handshake communication and so on and which are generally unknown to an average electronic engineer.

One such language is called Petri Nets. At Newcastle, scientists are developing a design system which overcomes this problem by automatically translating a Petri Net description of the intended circuit behaviour into an orthodox logic design language as asynchronous circuit designs are mapped out.

Such innovations are making asynchronous technology a more attractive commercial proposition and there are signs that the world is now at the dawn of the transitional period.

Scientists talk of an intermediate class of systems being developed and called GALS for globally asynchronous, locally synchronous. It is an open secret in IT circles that international electronics company Philips has produced an experimental pager built from asynchronous circuits and is developing other devices based on the same principle.

It is also rumoured that a leading manufacturer is designing the next generation of computer processor with at least some asynchronous elements. Time moves on as times change.

For more information contact Mick Warwicker, Newcastle University, 0944 191 222 7850, or see


Further reading:

  • Interface adaptor for Farnell’s RIoTboard
    19 November 2014, Electrocomp Express, Computer/Embedded Technology
    Farnell element14 has released an adaptor that allows its RIoTboard development platform to interface with a variety of accessory types that do not natively interface to the board. It offers users the ...
  • PCI Express external cabling adaptor card
    19 November 2014, Rugged Interconnect Technologies, Computer/Embedded Technology
    Made by EKF, the SX2-SLIDE is a CompactPCI Serial host adaptor card for PCIe x 4 external cabling. It allows control of a remote PCI Express-based target (downstream) system by a CompactPCI Serial ...
  • Reference designs for Industry 4.0
    19 November 2014, CST Electronics, Computer/Embedded Technology
    Using the Micro PLC platform from Maxim Integrated, designers now have the tools to implement Industry 4.0 with less power, parts and total costs. The trend of Industry 4.0 marks a move of factory systems ...
  • Computers for transportation market
    19 November 2014, Zitera Holdings, Computer/Embedded Technology
    Kontron’s TRACe family of operational computers, designed specifically for the transportation market, is designed to deliver proven, rugged and feature-rich building blocks that allow design flexibility. ...
  • Profinet digital I/O modules
    8 October 2014, Molex-Connector & Interconnect Div., Computer/Embedded Technology
    Molex has released a new Ethernet version of its Brad HarshIO compact 30 mm modules. Designed to provide industrial fieldbus connectivity for Profinet, the new modules offer a cost-effective, IP67-rated, ...
  • EtherCAT servo drives
    8 October 2014, Vepac Electronics, Computer/Embedded Technology
    Panasonic servo drives now come with an Ethernet interface for the open network EtherCAT, which enables real-time communication between master and slaves. The company’s MINAS A5 servo drives series has ...
  • Dual frequency synthesiser module
    8 October 2014, Conical Technologies, Computer/Embedded Technology
    The Valon 5008 dual frequency synthesiser module provides two independent frequency sources suitable for high-quality clock, carrier, or local oscillator frequency generation applications. An integral ...
  • Arduino board ups performance ante
    17 September 2014, RS Components (SA), Computer/Embedded Technology
    RS Components announced it is shipping the latest and most powerful Arduino board released to date. The new Arduino TRE is essentially two Arduino boards in one: it combines a Texas Instruments 1 GHz ...
  • Profibus interface cards
    17 September 2014, Computer/Embedded Technology
    Molex has introduced new-generation Brad applicomIO Profibus network interface cards (NICs), which are form-fit-function replacements for the existing family. The boards provide an easy-to-use communication ...
  • Tough Mini-ITX motherboard
    17 September 2014, Zitera Holdings, Computer/Embedded Technology
    With the launch of the embedded motherboard KTQM87/mITX, Kontron has extended its long-term available Mini-ITX portfolio to include a vibration- and shock-proof motherboard with a soldered 4th generation ...
  • Rugged Gigabit Ethernet switch
    17 September 2014, Electronic Products Design, Computer/Embedded Technology
    The rugged Raptor-Epsilon from Diamond Systems is a Layer 2+ Ethernet switch providing advanced features such as VLAN, aggregation, jumbo frame support, programmable multi-layer classifier with eight ...
  • Atom-based embedded computing boards
    17 September 2014, Centurion Micro Electronics, Computer/Embedded Technology
    Avalue Technology has released three new embedded boards powered by Intel’s latest Atom processor E3800 product family which is based on a 22 nm microarchitecture designed for fanless intelligent systems ...

Technews Publishing (Pty) Ltd
1st Floor, Stabilitas House
265 Kent Ave, Randburg, 2194
South Africa
Publications by Technews
Dataweek Electronics & Communications Technology
Electronic Buyers Guide (EBG)

Hi-Tech Security Solutions
Hi-Tech Security Business Directory

Motion Control in Southern Africa
Motion Control Buyers’ Guide (MCBG)

South African Instrumentation & Control
South African Instrumentation & Control Buyers’ Guide (IBG)
Terms & conditions of use, including privacy policy
PAIA Manual


    Classic | Mobile

Copyright © Technews Publishing (Pty) Ltd. All rights reserved.