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CLOCKLESS CHIPS

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Submitted by
M.VEDAVATHI
07601F0037
III MCA

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INTODUCTION
CLOCKLESS CHIPS OR ASYNCHRONOUS CHIPS DONâ„¢T HAVE A GLOBAL CLOCK.
BUT THERE SHOULD BE SOME CONTROL MECHANISM INSTEAD OF GLOBAL CLOCK.
CLOCKED CHIPS OR SYNCHRONOUS CHIPS HAVE A GLOBAL CLOCK FOR CONTROLLING TIMING OF ENTIRE CHIP.
CLOCKLESS CHIPS HAVE SOME ADVANTAGES LIKE LOW POWER CONSUMPTION,HIGH SPEED & LESS ELECTROMAGNETIC NOISE OVER CLOCKED CHIP.


CONCEPT OF CLOCK
Clock is a tiny crystal oscillator. Clock regulates the rate at which the instructions are executed. This rate is known as clock rate or clock speed. The clock speed can be expressed in terms of gigahertz and megahertz.
One advantage of clock is that the clock signals to various components inside a chip when to input and output can be determined very easy.
Because of this clock there are some disadvantages like high power consumption, low speed which can be overcome by clockless chips.
BLOCK DIAGRAM OF SYNCHRONOUS CIRCUIT
SYNCHRONOUS CHIPS



ADVANTAGE
CHIP DESIGN VERY SIMPLE BECAUSE OF CLOCK


DISADVANTAGES
WASTAGE OF COMPUTATIONAL TIME AFFECTS THE SPEED OF CHIP
HIGHER POWER CONSUMPTION
DESIGN OF COMPLEX CIRCUITS CANNOT BE DONE BECAUSE OF HIGH POWER CONSUMPTION


BLOCK DIAGRAM OF ASYNCHRONOUS CHIPS
MERITS OF ASYNCHRONOUS CIRCUITS
Increase in speed.
Reduced power consumption.
Less electromagnetic noise.
The ability to provide superior encryption.
It is very flexible.
Replacing any part with a faster version improves the speed again and again
Designers have more freedom in choosing the systemâ„¢s part.


LIMITATIONS OF ASYNCHRONOUS CIRCUITS
Design difficulties.
Lack of good tools.
Testing difficulties.
TYPES OF IMPLEMENTATIONS
BOUNDED DELAY METHOD
DELAY INSENSITIVE METHOD
NULL CONVENTIONAL LOGIC(NCL)

SPEED COMPARISON
POWER COMPARISON



A BRIEF HISTORY
The Caltech Asynchronous Microprocessor is the worldâ„¢s first asynchronous microprocessor (1989).



APPLICATIONS
PERSONAL COMPUTERS
ENCRYPTION DEVICES
MOBILE ELECTRONICS


CONCLUSION
Clocks are getting faster, while chips are getting bigger, both of which make clock distribution harder. Chips are also becoming more heterogeneous, with functions like memory and network interfaces being considered, all of which complicates the global timing analysis necessary for a synchronous design. Finally, we are entering an age when processors will be just about everywhere, and this will require very low power designs. Itâ„¢s just not practical to expect a clean, skew-free clock for every (say) piece of clothing with a processing element.
But this can only happen if more focus, especially at the university level, is given to asynchronous design. Most of todayâ„¢s designers donâ„¢t understand it well enough to use it, and may even regard it with suspicion. It is certainly a challenge, but just as the software community is moving towards more concurrency, the hardware community must move to incorporate asynchronous logic.






CONTENTS
1. INTRODUCTION
2. BASIC CONCEPT OF CLOCK
3. WORKING OF SYNCHRONIZE CHIPS
4. ADVANTAGES & DISADVANTAGES
5. WORKING OF ASYNCHRONOUS CHIPS
6. ADVANTAGES AND DISADVANTAGES
7. TYPES OF ASYNCHRONOUS DESIGN
8. COMPARISON
9. APPLICATIONS OF CLOCKLESS CHIPS
10. BRIEF HISTORY
11. CONCLUSION




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