A Memory Implementation of a Fully Programmable Digital Controller

An electronic interface or a data processor, here called a "stored program processing computer" (SPPC), usually consists of two types of circuits: the information circuits and the control circuits. Information circuits are those that store data permanently or temporarily and/or process information (data) performing either logic or algebraic operations. The control circuit, usually called the controller, comprises the 1599 heart of the system and is responsible for the normal flow of information in a well-defined environment with preprescribed control functions in space and in time. The principle of a system is illustrated in Fig. 1. In this illustration, the controller is subject to external conditional signals according to which it controls (regulates) the flow of information through and from circuit to circuit (1 through 3 in Fig. 1). Each information circuit may have, theoretically, any number of inputs and any number of outputs, and each one may be connected with any other information circuit in one given direction or in both. In this paper, the term SPPC applies to both analog or digital computer, assuming that the controller is digital, as is the usual case. In the design of an electronic system, a considerable amount of the design effort is consumed in the controller circuit. The controller usually is a sequential random logic circuit, and it should be simple, fast, and, above all, error-free or glitchless, thus making it a laborious design of state machines.1'2 Additionally, in certain applications the controller should be flexible or programmable so that the controlling functions could be altered according to the different requirements of the particular application.