Design of Asynchronous Sequential Networks Using Read-Only Memories

Abstract

The application of microprogrammed READ-ONLY memories in the design of asynchronous sequential networks is investigated. Variations of single-transition time (STT) state assignments are shown to be applicable to the problem of assigning memory addresses to a memory representation of an asynchronous network. Design algorithms are developed which allow the implementation of an asynchronous sequential network as a READ-ONLY memory. Two operating modes are considered: normal asynchronous operation and a self-clocked mode in which sequential outputs are allowed on a single-input change, thus providing a means of implementing functions normally achieved with synchronous (clocked) networks. In addition the practical timing constraints of the proposed methods are considered.