Addressing the tradeoff between standard and custom ICs in system level design

Abstract: "Digital design at the system level considers the implementation of a system with some mix of standard ICs, custom ICs, and software. In the early stages of design the system is described by a set of descriptions which may include software, hardware behavioral descriptions, and specifications for standard parts. The implementation implied by the initial set of descriptions, however, may not meet system performance goals (i.e. cost, throughput, physical size). The challenge of the early design stages, then, is to rework the set of descriptions into one whose implementation meets the performance goals. One possibility is to consider designing custom ICs for some parts of the system.This may be an attractive alternative when only a subset of the functionality of a standard IC is needed by the system, or when the standardIC implementation represents a poor use of PC board space (i.e. many SSI or MSI parts). This paper formalizes the tradeoff between using a custom IC and using standard ICs to implement part of a system. The new design tool described in this paper brings together system-level andbehavioral-level synthesis paradigms and is capable of designing microprocessor-based computer systems which include an ASIC. Effective useof the ASIC's gate capacity and I/Os results in designs which require as little as 62% of the PC board area needed by designs with no ASIC."