State Assignment of Finite-State Machines by Using the Values of Input Variables

In this paper, we propose the method of FSM synthesis on field programmable gate arrays (FPGAs) when input variables are used for state assignment. For this purpose we offer a combined structural model of class A and class E FSMs. This paper also describes in detail the algorithms for synthesis a class AE FSM which consists of splitting of internal states for performance of necessary conditions for synthesis of the class E FSM and state assignment of the class AE FSM. It is shown that the proposed method reduces the area for all families of FPGAs by a factor of 1.19-1.39 on average and by a factor of three for certain families. Practical issues concerning the method and the specific features of its use are discussed, and possible directions of the elaboration of this approach are proposed.