Lsi Logic Corporation

Simon Dolan

Christian Joly

An ASIC design methodology in which portions of the ASIC are implemented in silicon or other suitable semiconductor technology at an early stage in the design flow through the use of a series of interim devices. The invention provides a method in which additional portions or subsystems of the integrated circuit are incorporated into successive versions of the interim device. In this manner, the invention provides for the gradual incorporation of a plurality of architectural subsystems into the integrated device such that the synthesis and verification of each iteration is broken into manageable pieces. In the preferred embodiment, this design method is facilitated by incorporating a programmable portion into the design flow of each interim device such that each interim device includes a custom portion into which the subsystems that have been implemented in silicon are fabricated and a programmable portion. The programmable portion is useful in permitting the designer to make modifications to the subsystems implemented in the custom portion or to simulate the subsystems of the target device that have yet to be implemented in the custom portion.

Method for designing application specific integrated circuits

An integrated circuit comprised of a customized circuit portion and a programmable logic portion that is interfaced to the customized circuit. The custom circuit and the programmable circuit are fabricated on a common semiconductor substrate to achieve maximum cost savings and performance advantages over implementations in which an external PLD or other programmable device is interfaced to a custom circuit. Suitably, the customized circuit is designed with an ASIC design flow to optimize the performance, power consumption, and size of the customized circuit. In the presently preferred embodiment, the programmable circuit comprises a plurality of programmable logic cells suitably generated by, in one embodiment, a PLD compiler. Ideally, the relative size and placement of said PLD with respect to said customized circuit are selectable during a design phase of said integrated circuit. This provides flexibility in determining how much of an interim device need be devoted to programmable circuitry. Presumably, during earlier stages of the design process, a larger percentage of the device will be devoted to the programmable portion. As the product definition matures, subsequent interim devices contemplated herein require less programmable logic.

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Los Gatos, CA, United States of America

Simon Dolan