G. Lee et al., ETDD-based synthesis of two-dimensional cellular arrays for multi-output incompletely specified Boolean functions, IEE P-COM D, 146(6), 1999, pp. 302-308
Complex terms are logic expressions which can be mapped directly to cell ar
rays of cellular architecture devices such as Atmel 6000 series FPGAs. The
paper presents an approach to the generation of complex terms for multi-out
put incompletely specified Boolean functions using EXOR ternary decision di
agrams ETDDs. The expansions, Shannon, positive Davio and negative Davio, i
nherent in ETDDs, are employed to generate complex terms. While traversing
the ETDD can be accomplished in a simple and efficient way for completely s
pecified functions, the manipulation of ETDDs with don't care terms becomes
very complex because the three expansions require different evaluations of
the function. The changes made to the function due to don't cares in each
expansion are analysed, and an approximation algorithm is presented with it
s applications to the minimisation of functions composed of complex terms.