AN OPTIMUM HALF-HOT CODE ASSIGNMENT ALGORITHM FOR INPUT ENCODING AND ITS APPLICATION TO FINITE-STATE MACHINES

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.