Provably correct storage arrays

Abstract

A hardware design technique allows checking of design system language (DSL) specification of an element and schematics of large macros with embedded arrays and registers. The hardware organization reduces CPU time for logical verification by exponential order of magnitude without blowing up a verification process or logic simulation. The hardware organization consists of horizontal word level rather than bit level. A memory array cell comprises a pair of cross-coupled inverters forming a first latch for storing data. The first latch has an output connected to a read bit line. True and complement write word and bit line input to the first latch. A first set of pass gates connects between the true and complement write word and bit line inputs via gates and the input of said first latch. The first set of pass gates is responsive to a first clock via a second pass gate. A pair of cross-coupled inverters forms a second latch of a Level Sensitive Scan Design (LSSD). The second latch has output connected to an LSSD output for design verification. A second pass gate connects between the output of the first set of pass gates and the input of said first latch. The second pass gate is responsive to said first clock. A third pass gate connects between the output of said first latch and the input of said second latch. The third pass gate is responsive to a second clock. The first and second clocks are responsive to a black boxing process for incremental verification.