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The concept of modularity enables parallelization of the design process. Locality: The concept of locality in system ensures that the internal details of each Answer: VLSI Design flow consists of several steps which are carried out in linear . VLSI Design Methodologies EEB (Winter ): Lecture # 4Mani of Structured Design Techniques Hierarchy Regularity Modularity Locality; . architecture structure of accumulator is component reg — definition of. Digital VLSI Circuits. 1. Introduction to ASIC Design a. Design Strategies: Hierarchy, Regularity, Modularity & Locality b. Chip Design Options: Gate Array, Field.

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In this way, we hide information in an attempt to reduce the apparent complexity of a module. At that time, a minimum feature size of 0. Here, one can identify four different design styles on one chip: Such changes may require significant modification of the original requirements.

The most rigorous full custom design can be the design of a memory cell, be it static or dynamic. The Y-chart first introduced by D. Initial design is developed and tested against the requirements. There is no Metal2 keep out indicating that we can route Metal2 kodularity over the cell.

The magic router also supports the labelling style shown below which uses rectangles for port labels: Wiring should not normally overlap a sub-cell.

Notice that within the cell block, the separations between neighboring rows depend on the number of wires in the routing channel between the cell rows.

By defining well-characterized interfaces for each module in the system, we effectively ensure that the internals of each module become unimportant to the exterior modules. Each design style has regularitt own merits and shortcomings, and thus a proper choice has to be made by designers in order to provide the functionality at low cost.


The characterization of each cell is done for several different categories. At the transistor level, uniformly sized transistors simplify the design. If necessary, the replication of some logic may solve this problem in large system architectures.

More sophisticated CLBs have also been introduced to map complex functions. The simplest common specification for the keep out area is as follows: Where modules are well-formed, the interactions with other modules are easy to characterize.

Hierarchy Rules for Layout

The LUT is a digital memory that stores the truth table of the Boolean function. Modularity Sub-modules must have well-defined functions and interfaces. Other than this 0. A good example of regularity is the design of array structures consisting of identical cells – such as a parallel multiplication array.

The monolithic integration of a large number of functions on a single chip usually provides:. For timing critical paths, proper gate sizing is often practiced to meet the timing requirements. When requirements are not met, the design has to be improved. This design style provides a means for fast prototyping and also for cost-effective cojcept design, especially for low-volume applications. A more detailed view showing the locations of switch matrices used for interconnect routing is given concfpt Fig.

In the following, we will examine design methodologies and structured approaches which have been developed over the years to deal with both complex hardware and software projects.

At the logic level, identical gate structures can be used, etc. These modules are then geometrically placed onto the chip surface using CAD tools for automatic module placement followed by routing, with a goal of minimizing the modularrity area and signal delays. Internal details remain at the local level. However, it is important for the simplicity of design that the hierarchies in different domains can be mapped into each other easily.


After routing is completed, the on-chip. The current leading-edge technologies such as low bit-rate video and cellular communications already provide the end-users a certain amount of processing power and portability. The design complexity of logic chips regularith almost exponentially with the number of transistors to be integrated.

Design of VLSI Systems – Chapter 1

To enable automated placement of the cells and routing of inter-cell connections, each cell layout is designed with a fixed height, so that a number of cells can be abutted side-by-side to form rows. These uncommitted chips can be stored for later customization, which is completed by defining the metal interconnects between the transistors of the array Fig.

When comparing the integration density of integrated circuits, a clear distinction must be made between the memory chips and logic chips. Although supported by magic, this style is not supported by Tanner L-Edit. The interconnection patterns to realize basic logic gates can be stored in a library, which can then be used to customize rows of uncommitted transistors according to the netlist.

Memory banks RAM cachedata-path units consisting of bit-slice cells, control circuitry mainly consisting of standard cells and PLA blocks.