Motorola Corporation

David J Wagner

Dean M Picha

Stephen G Oller

Robert J Laping

A main microprocessor A (11) provides data to a display formatter microprocessor B (12) via a data bus (13). Microprocessor B provides data and latch (activity) pulses (34A) to a visual display (27) comprising a number of individual display devices (28-30) which are sequentially excited by data obtained from microprocessor B. An external activity detector (38), in response to an absence of the latch pulses of microprocessor B for a predetermined time, generates a reset signal (40) for resetting the microprocessor A. In response to being reset, microprocessor A provides an output control signal (at 20) which results in the resetting of the microprocessor B. If microprocessor B determines that microprocessor A is not properly providing data to it, microprocessor B will terminate generating the latch pulses (34A). The preceding configuration results in each of the microprocessors effectively monitoring the operation of the other microprocessor so as to insure proper system operation. Therefore, this system properly resets itself in response to any of a large number of different failures which may occur in either of the microprocessors, and this is accomplished with a minimum of additional hardware circuitry and software programming.

Multiple microprocessor watchdog system

An electronic turn signal cancellation apparatus is disclosed which includes two separate rotational positions sensing elements, each sensing an associated identifying portion positioned on a shaft rotated in accordance with vehicle steering wheel rotation. An electronic turn signal cancellation circuit, which may be effectively implemented by a microprocessor, effectively analyzes the output signals of these sensors and determines the current angular shaft position and also the previous shaft position. Turn signal cancellation is implemented by determining current shaft position and the direction of rotation of the shaft. One embodiment implements turn signal cancellation without hysteresis, while a second embodiment utilizes similar structure to implement turn signal cancellation with hysteresis. In each case only two sensors are utilized which may be joined together to form a unitary sensor assembly.

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Lake Zurich, IL, United States of America

David J Wagner