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Unformatted text preview: Principles of VLSI Design Representations CMPE 413 1 UMBC U M B C U N IV E R S I T Y O F M A R Y L A N D B A L T IM ORE COU NTY 1 9 6 6 Circuit and System Representations IC design is hard because designers must juggle several different problems: • Multiple levels of abstraction: ICdesignsrequiresrefininganideathroughmanylevelsofdetail,speci- fication -> architecture -> logic design -> layout. • Multiple conflicting costs: Designs can be judged against different criteria. Most important criteria include speed, area and power. If both speed and area constraints are to be satisfied simultaneously, many design decisions will improve one at the expense of the other. Design is dominated by process of balancing conflicting constraints. • Short design times: Chips that appear too late may make little or no money because of com- petitors. Design time is especially tight for ASICs. Principles of VLSI Design Representations CMPE 413 2 UMBC U M B C U N IV E R S I T Y O F M A R Y L A N D B A L T IM ORE COU NTY 1 9 6 6 Circuit and System Representations Two techniques used by designers to eliminate unnecessary detail: Hierarchical design: Divide and conquer, complexity is reduced by recursively breaking it down into manageable parts. Each level of the hierarchy adds complexity by adding components. Commonly used in programming. Design abstraction: Complexity is reduced by successively replacing detail with simplifica- tions at higher levels of abstraction. Number of components do not change as it is recast to a lower level of abstraction. Less common in programming. Design abstraction and hierarchical design are not the same thing. A design hierarchy uses components at the same level of abstraction. Principles of VLSI Design...
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This note was uploaded on 08/23/2009 for the course CMSC 711 taught by Professor Chintanpatel during the Fall '04 term at UMBC.
- Fall '04