15.8  Summary

The construction or physical design of ASICs in a microelectronics system is a very large and complex problem. To solve the problem we divide it into several steps: system partitioning, floorplanning, placement, and routing. To solve each of these smaller problems we need goals and objectives, measurement metrics, as well as algorithms and methods.

System partitioning is the first step in ASIC assembly. An example of the SPARCstation 1 illustrated the various issues involved in partitioning. Presently commercial CAD tools are able to automatically partition systems and chips only at a low level, at the level of a network or netlist. Partitioning for FPGAs is currently the most advanced. Next we discussed the methods to use for system partitioning. We saw how to represent networks as graphs, containing nets and edges, and how the mathematics of graph theory is useful in system partitioning and the other steps of ASIC assembly. We covered methods and algorithms for partitioning and explained that most are based on the Kernighan–Lin min-cut algorithm.

The important points in this chapter are

• The goals and objectives of partitioning
• Partitioning as an art not a science
• The simple nature of the algorithms necessary for VLSI-sized problems
• The random nature of the algorithms we use
• The controls for the algorithms used in ASIC design

[ Chapter start ] [ Previous page ] [ Next page ]