DacTapePrompts.tioga
Louis Monier April 26, 1988 8:46:06 am PDT
It is time to put a halt to this recursive walk through the shift register,
but it is clear that after another couple of steps,
the shift register would be completely described in term of basic gates and D flip-flops.
In short we've emphasized two ideas:
code is an integral part of the source,
and code plus parameterized schematics form an extremely powerful circuit description language.
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We've just seen an pristine example of tight integration.
The simulator communicates with the designer in terms of the original source, be it test vectors or schematics.
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The data path is a good example of the extensibility of our system architecture. It was added to the system by a designer because he needed it to optimize a portion of his chip. It uses the standard editor and user interface.
Our data path generator allows detailed control of placement and routing to exploit the regularity inherent in a data path.
Unlike other data path generator systems the clocking style, number of buses, types of register banks and so on are not constrained in any way.
Instead the designer can implement any net list he likes.
The purpose of the data path generator is to help him organize the tiling of the silicon plane.
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Even though our system was developed in a research environment with limited manpower, it has produced many examples over the past three years. In fact, it has been stress tested with a variety of large circuits close to the state-of-the-art in complexity.
A remarkable aspect of the system is the size of the source for the circuits: here is a 170,000 transistors circuit, layed out with standard cells and standard memory blocks.
The entire source description for this circuit fits here.
Because it uses standard components, its implementation took only one man-month.
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This completes the tour through our system.
In this tape we emphasized the explanation of a few basic principles rather than a complete review of all the tools available.
Timing analysis, design rule checking, layout vs. schematic comparison, and circuit simulation are examples of tools which we did not have time to present.
All of these features help people be more productive. They reduce the time and the number of people required to design integrated circuits.