Uploaded byAkshit Arora
Asynchronous Processors - The Clock less Future
The document discusses asynchronous microprocessors, which operate without a global clock and allow components to run at different speeds, enhancing power efficiency and performance. It outlines the advantages and disadvantages of asynchronous design, a brief history of key developments in the field, and concludes that such designs have become viable and competitive with synchronous designs. Notable advancements, including the development of the world's first bendable microprocessor, signify the potential for asynchronous architecture in future computer science applications.
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Asynchronous Processors - The Clock less Future
- 1. Asynchronous Microprocessor The Clockless Future ComputerScience Architecture Presentation By : AkshitArora (101303012) Ankit Goyal (101303022)
- 2. “Designers are realizingthat distributing a clock across ever more complicated systems is becoming more and more difficult, and that sooner or later it won't work” Alain Martin Professor Computer Science Caltech built the first clockless microprocessor in 1989
- 3. What are AsynchronousProcessors ? • An asynchronous circuit, or self-timed circuit, is a sequential digital logic circuit which is not governed by a clock circuit or global clock signal. • Unlike a conventional processor, a clockless processor (asynchronous CPU) has no central clock to coordinate the progress of data through the pipeline.
- 4. It may actuallybe even easier to implement high performance devices in asynchronous, as opposed to clocked, because: Components can run at different speeds on an asynchronousCPU. All major components of a clocked CPU must remain synchronized with the central clock. A traditional CPU cannot “GO FASTER" than the expected worst-case performance of the slowest stage/instruction/component. When an asynchronousCPU completes an operation more quickly than anticipated, the next stage can immediately begin processing the results, rather than waiting for synchronization with a central clock.
- 5. Why Asynchronous Design •Better Power Efficiency • Only activating functional units consume power • Inactivated parts remain in “stand-by” state • No wasteful power dissipation by glitches • Higher Performance • No global clock • proceed data at appropriate rate of environment • Do not propagate local delay globally • Smaller Chip Size • Less high-frequency EMI components due to small amplitude and wide current peaks
- 6. Disadvantages • Fewer peopleare trained in this style compared to synchronous design. • Performance (speed) of asynchronous circuits may be reduced in architectures that require input-completeness (more complex data path). • Incompatible with commercial EDA tools
- 7. Brief History ofAsynchronous Processors ILLIAC I and ILLIAC II (first asynchronous designs, University of Illinois)1952 The PDP6 (Programmed Data Processor-6) DEC in 1960 was an asynchronous computer model1960
- 8. Brief History ofAsynchronous Processors •It was all forgotten because of timing and hiding advantages of Clocked processor until the arrival ofVLSI in early 1970s •The first Caltech Conference onVLSI in 1979 had a complete session on self-timed logic, as asynchronous logic was called at the time, within an important paper by Stucki and Cox on ‘synchronization strategies’ was presented.
- 9. Brief History ofAsynchronous Processors The first single-chip asynchronous microprocessor was designed at Caltech1988 The first family of asynchronous clones of the ARM processor (Amulet) from University of Manchester1993 An 8-bit microprocessor byTokyo Institute ofTechnology namedTITAC1994 Amulet2e andTITAC 21997
- 10. Brief History ofAsynchronous Processors • Also, in 1997,The Caltech group designed the MiniMIPS—an asynchronous version of the 32-bit MIPS R3000 microprocessor. • With a performance close to four times that of a clocked version in the same technology for the first prototype, the MiniMIPS is still the fastest complete asynchronous processor ever fabricated.
- 11. Brief History ofAsynchronous Processors • In 2004, Epson manufactured the world's first bendable microprocessor called ACT11, an 8-bit asynchronous chip. • using low-temperature polysilicon thin-film transistors on a plastic substrate • With energy consumption reduced by 70 per cent compared to the synchronous microprocessors now in everyday use. • Epson is now researching potential applications for its invention
- 12. Conclusion • It isentirely practical to design a processor without a clock. • Quality of such processors have improved with time. Some are commercially available • Clockless and selftimed processors opens up horizons for a radical departure in the main stream architectures to new and exciting areas. • Asynchronous design is competitive with the best synchronous design in power efficiency and is close in performance to them.
- 13. References • http://www.electronicsforu.com/EFYLinux/efyhome/cover/January2008/Asy nchronous%20Microprocessor.pdf • http://en.wikipedia.org/wiki/Asynchronous_circuit#Asynchronous_CPU •http://www.ubergizmo.com/2005/02/epson-develops-the-worldacutes-first- flexible-8-bit-asynchronous-microprocessor/
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