Transcript Clockless Processors

Roadmap
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History
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Synchronized vs. Asynchronous overview
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How it works
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Benefits of clockless chips
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Limitations of clockless chips
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Potential for the future
How fast is your computer?
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Speed of clock
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Billionth of a second long
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All operations governed by speed of clock
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Many operations take different speeds
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Must be coordinated
History
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Asynchronous design considered in 1946 by
Alan M. Turing

David A. Huffman and David E. Muller
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ILLIAC II (1962)
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Was not reliable with technology of the time

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Vacuum tubes and relay circuits
Moore's law
Disadvantages of clock
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Process of diminishing returns
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Slowest process governs speed
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Clock runs during idle time

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Increased power consumption
Speed of light
Asynchronous Processor
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Event driven
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System of local handshaking
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No global clock
Needs way govern processes
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Signals indicate completion
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Employes Rendezvous and
Arbiter gates
Asynchronous Processor (cont.)
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
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State of circuit changes instantly with signal
Varying speed patterns results in varying
electromagnetic waves
Design must account for speed patterns
Asynchronous Processor (cont.)
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Without clock, must know when operation is
done
Dual-rail circuits

Yes, no, or no answer yet
Delay-Intensive Model
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Makes no assumptions
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All transistors must be acknowledged
Principle of their advantages
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Variable length processes

division
Do they exist?


ARM Holdings and Handshake Solutions

ARM996HS

Proposed for use in automotive/medical
equipment
Philips


Pagers
Intel, IBM, Sun
Benefits of Clockless chips
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Executing of individual functions does not
wait for next clock pulse

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Less power consumption

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Up to 3 times faster
Idle time
Lower electromagnetic pulse
Limitations
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Lack of automated designing/testing tools
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Strict attention to physical design

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Lengths of wires, logical gates
Predicting complex sequences and
coordinating
Inhibitors of Development
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Pace of market competition

Education
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Synchronous easier to test
Conclusion
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Many advantages over synchronous
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Handshakes and coordination circuits
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Implementation lengthy, lack of resources
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Physical limitations of clock
References
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http://iqmagazineonline.com/IQ/IQ17/LowRes.
pdfs/Pgs20-24_IQ17.pdf
http://www.technologyreview.com/featuredstory/401226/its-time-for-clockless-chips/2/
http://www-classes.usc.edu/engr/ees/552/coursematerials/ee552-H5.pdf
http://www.youtube.com/watch?v=xXL8oYmkt
qM&feature=related
http://www.eetimes.com/electronicsproducts/processors/4082174/ARM-offers-