The Full-decomposition of Sequential Machines with the Separate Realization of the Next-state and Output Functions

The decomposition theory of sequential machines aims to find answers to the following important practical problem: how to decompose a complex sequential machine into a number of simpler partial machines in order to: simplify the design, implementation and verification process; make it possible to process (to optimize, to implement, to test, ••. ) the separate partial machines al though it may be impossible to process the whole machine with existing tools; make it possible to implement the machine with existing building blocks or inside of a limited silicon area. For many years, decomposition of the internal states of sequential machines has been investigated. Here, decomposition of the states, as well as, the inputs and outputs of sequential machines is considered, i.e. full-decomposition. In [16], classification of full-decompositions is presented and theorems about the existence of different full-decompositions are provided. In this report a special full-decomposition strategy is investigated the full-decomposition of sequential machines with the separate realization of the next-state and output functions. This strategy has several advantages comparing to the case where a sequential machine is considered as a unit. In the report, the results of theoretical investigations are presented; however, the notions and theorems provided here have straightforward practical interpretations and they can be directly used in order to develope programs computing different sorts of decompositions for sequential machines. INDEX TERMS Automata theory, decomposition, logic system design, sequential machines. ACKNOWLEDGEMENTS The author is indebted to Prof. ir. A. Heetman and Prof. ir. M. P.J. Stevens for making it possible to perform this work, to Dr. P.R. Attwood for making corrections to the English text and to mr. C. van de Watering for typing the text.