Random pattern lock and key fault detection scheme for microprocessor systems

摘要

A microprocessor-based electronic control unit utilizes a random pattern lock and key failure detection scheme to detect failures in the system being controlled or the control unit itself. The microprocessor system is programmed to receive a random data word, to output the same data word, and to perform a variety of tests which result in the generation of a data stream having a particular relationship to the random data word such that the data stream and the random data word bits can be combined to form a predetermined data word that is needed to maintain microprocessor control of the associated electrical system. If the microprocessor fails to generate a data stream which results in the formation of the proper predetermined data word, the control unit output will be locked into a predetermined state.