Y. Nagata et al., AN OPTIMUM HALF-HOT CODE ASSIGNMENT ALGORITHM FOR INPUT ENCODING AND ITS APPLICATION TO FINITE-STATE MACHINES, IEICE transactions on information and systems, E78D(10), 1995, pp. 1231-1238
In this paper, a new optimum input encoding algorithm with m-out-of-2m
code which is called Half-Hot Code is presented. By applying Half-Hot
Code to the input encoding in PLA-based digital system, the logic fun
ctions of the system turn out to be unate functions, thus, the number
of bit-lines of PLA may be reduced[1]. The proposed method further red
uces the number of product-lines of PLA optimally. In this code assign
ment procedure, computed Boolean subspaces satisfying suggested two co
nditions are assigned to each partitioned subset of digital input vari
ables which are obtained by disjoint minimization or other techniques.
As an experiment to evaluate the method, the state assignment for fin
ite state machines of two-level implementation is considered. Specific
ally, the proposed Half-Hot Code assignment is compared with arbitrary
Half-Hot Code assignment. The results show that the optimum encoding
is superior to an arbitrary assignment up to about 24% in the number o
f product-lines of PLA.