내부 Dont't care를 이용한 이차원 셀 배열의 새로운 합성 방법

A New Approach to the Synthesis of Two-Dimensional Cellular Arrays Using Internal Don't Cares

This paper presents a new approach to the synthesis of two-dimensional arrays such as Atmel 6000 series FPGAs using internal don't cares. Basically complex terms which fits to the linear array of cells without further routing wires are generated and they are collected by OR/XOR operations. In previous methods, complex terms are collected only by XOR operations, which may not be effective for nearly unate functions. In this paper, we allow complex terms to be collected by OR operations in addition to XOR operations. First, complex terms that lies in the ON-set of the function are generated and collected by OR operations. The sub-function realized by the first stage becomes an internal don't cares and they are exploited in the second stage which generates complex terms collectable by XOR operation. Experimental results shows the efficacy of the proposed method compared to the previous methods.