An integrated CAD environment for system design

An integrated CAD (computer-aided design) environment that leverages publicly available CAD tools is described. Tools not suitably available and tools integration software are added to this base set of tools to complete the system. The CAD system is based on a top-down design and verification methodology that includes feedback from lower design levels to higher levels. At its heart are central data structures containing all design and characterization information. Software layers built on the central data structures include object manipulators to access the data structures; readers and writers for format conversion; CAD tools for synthesis, simulation, comparison, back annotation, and translation; and shell scripts performing tasks of the methodology. Design entry can be done with both schematics and algorithmic description. Both entry forms update the central data structures, thus ensuring consistency of all design descriptions