INNOVATIVE CONCEPT FOR HIGH-SPEED I/O PROCESSOR DEDICATED TO ENGINE CONTROL SYSTEM

On account of the increase of complexity of the engine control systems, microcontrollers of Electronic Control Units need to be more sophisticated regarding the process of timing functions which is the heart of the system. Conventional microcontrollers use timers with capture and compare registers to achieve the control functions required. However, the CPU needs to interact to a large extent with timers and dedicated registers. This interaction reduces dramatically the processing power available for the other functions. The paper describes the Texas Instruments modular TMS370 microcontroller Family which allow "custom" microcontrollers with dedicated engine High Speed Control and Acquisition (HSCA) control module. By combining input capture and output compare features, event counter and timers which are all software definable within a flexible RAM based organisation, time, event or event plus time related tasks are able to be set up in advance of their action and then release the CPU to operate independently of these tasks. Since all the HSCA control information is held within the register RAM, the CPU has easy and fast access to these parameters (i.e. duty cycle update of PWM outputs automatically driven by the HSCA module). The paper describes in detail how signals in engine control system such as spark time event, dwell time generation, dwell time feedback, fuel injection time, PWM signal outputs, knock window generation can be automatically driven by the HSCA and this completely independently of the CPU. The paper presents a static ignition and multi-points sequential fuel injection system using a TMS370 with the HSCA module. For the covering abstract of the conference see IRRD 850768.