Hardware Support for Automatic Routing

A system for automatic routing based on an iterative application of Lee´s algorithm is presented. An extended cell admissibility is defined for continuous design rules in coarse rectangular grids. Combined hardware and software design strategies are applied towards the definition of data structures and their kernel primitives for automatic routing. The hardware architecture and the implementation of specific structures are discussed. The resulting extended routing unit is used in a CAD system. Thus the throughput of the iterative router is improved by a factor of 5 compared to the equivalent software process. Finally the architecture of a high speed stand-alone routing processor is presented.