1. ABSTRACTAs electronics technology has made remarkable progress in recent years, 16-bit microcomputers have been increasingly employed in automotive engine control systems.Initially, engine control systems which could control only fuel injection and ignition timing might have been sufficient, but today, systems are increasingly being required to cover many control, such as knocking and intake control.In addition, demands for integrated engine control units that can also control other sub-units such as anti-lock braking control systems, traction control systems, and transmission control systems have been on a steady rise.Against this background, the following requirements will be demonstrated by the engine control systems of today and the future: 1) Integration on a microcomputer chip of powerful real-time control functions suitable for mechanical control 2) Miniaturization of unit size 3) Unification of control programs 4) Standardization of hardware Some of these requirements can be satisfied by employment of a high-speed microcomputerand large-capacity on-chip memory. However, accelerating the operating speed of the microcomputer and increasing the on-chip memory capacity are likely to increase the workload and the chip size of the microcomputer. This will not necessarily improve the overall performances of the control system.What microcomputer is the best for automotive engine control systems and how should the system itself be organized to meet all of the above requirements? In a bid to answer these questions, this paper discusses the LSI design techniques (especially microcomputers) to be used in engine control systems, placing a special emphasis on the advantages as well as disadvantages of multiple chip configurations for engine control systems.This paper also presents some application examples of the 16-bit single-chip microcomputer µPD78322 and of the (ASIC) µPD71P301 (nicknamed “turbo access manager”), whose architecture is designed using LSI design techniques which will be introduced in this paper.