This paper describes design using state-transition methodology. This state-transition methodology is straightforward, with a simply-perceived relation between the programming and the corresponding sequential function. The current operational function of the system is described as the current state of the system using state-transition programming. The state transition diagram or table describes the current state and the conditions for transition. The operation is transferred to a corresponding destination state when a set of conditions become valid for leaving the current state. Thus, the sequential operation is explicit, and any continuous conditions scanning (from command source and sensors) only include those that are pertinent for leaving the current state. The methodology is highly-structured and efficient, the programming tasks are readily comprehensible, and fault diagnostics can be easily included within the program's structure. The presented application of an automatic sliding-door illustrates the feasibility of this approach. This paper presents the MFSM (Modular Finite-State Machine), the ECA (Event-Condition-Action) system, motion generation, motion control with load estimation, and an example of a DSP (Digital Signal Processor) system. The limitations and attributes of each technique are discussed, and a state-table format is presented with the capability of representing parallel asynchronous sequential processes.