Multiple microprocessor watchdog system
First Claim
1. A multiple microprocessor watchdog system comprising:
- first microprocessor means A for generating output data on a first data bus and having an input reset terminal and an output control terminal, a control signal being provided at said output control terminal by said microprocessor means A in response to said microprocessor means A being reset;
second microprocessor means B coupled to said microprocessor means for receiving said data on said first data bus, processing said output data and providing said processed output data on a second data bus, said microprocessor means B having a reset input terminal, said microprocessor means B also having an activity output terminal at which activity pulses are periodically provided by said microprocessor means B, the existence of said periodic activity pulses being indicative of proper operation of said microprocessor means B;
utilization means coupled to said microprocessor means B for receiving and utilizing said processed output data on said second data bus; and
activity detector means coupled to said activity output terminal of said microprocessor means B for receiving said periodic activity pulses and providing a reset signal at an output terminal of said activity detector means in response to an absence of said periodic activity pulses;
the improvement comprising,said reset output terminal of said activity detector means being coupled to the reset input terminal of said microprocessor means A, and the control output terminal of microprocessor means A being connected to the reset input terminal of microprocessor means B, wherein detected activity failures of microprocessor means B result in said reset signal provided by said activity detector means resetting microprocessor means A and said microprocessor means A then resetting microprocessor means B.
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Accused Products
Abstract
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.
47 Citations
13 Claims
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1. A multiple microprocessor watchdog system comprising:
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first microprocessor means A for generating output data on a first data bus and having an input reset terminal and an output control terminal, a control signal being provided at said output control terminal by said microprocessor means A in response to said microprocessor means A being reset; second microprocessor means B coupled to said microprocessor means for receiving said data on said first data bus, processing said output data and providing said processed output data on a second data bus, said microprocessor means B having a reset input terminal, said microprocessor means B also having an activity output terminal at which activity pulses are periodically provided by said microprocessor means B, the existence of said periodic activity pulses being indicative of proper operation of said microprocessor means B; utilization means coupled to said microprocessor means B for receiving and utilizing said processed output data on said second data bus; and activity detector means coupled to said activity output terminal of said microprocessor means B for receiving said periodic activity pulses and providing a reset signal at an output terminal of said activity detector means in response to an absence of said periodic activity pulses; the improvement comprising, said reset output terminal of said activity detector means being coupled to the reset input terminal of said microprocessor means A, and the control output terminal of microprocessor means A being connected to the reset input terminal of microprocessor means B, wherein detected activity failures of microprocessor means B result in said reset signal provided by said activity detector means resetting microprocessor means A and said microprocessor means A then resetting microprocessor means B. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A multiple microprocessor watchdog system comprising:
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first microprocessor means A for generating output data on a first data bus and having an input reset terminal and an output control terminal, a control signal being provided at said output control terminal by said microprocessor means A in response to said microprocessor means A being reset; second microprocessor means B coupled to said microprocessor means A for receiving said data on said first data bus, processing said output data and providing said processed output data on a second data bus, said microprocessor means B having a reset input terminal, said microprocessor means B also having an activity output terminal at which activity pulses are periodically produced by said microprocessor means B as long as said microprocessor means B is operating properly, the existence of said periodic activity pulses being indicative of proper operation of said microprocessor means B; utilization means coupled to said microprocessor means B for receiving and utilizing said processed output data on said second data bus; and activity detector means coupled to said activity output terminal of said microprocessor means B for receiving said periodic activity pulses and providing a reset signal at an output terminal of said activity detector means in response to an absence of said periodic activity pulses; the improvement comprising, said reset output terminal of said activity detector means being coupled to the reset input terminal of said microprocessor means A, and the control output terminal of microprocessor means A being connected to the reset input terminal of microprocessor means B, wherein detected activity failures of microprocessor means B result in said reset signal provided by said activity detector means resetting microprocessor means A and said microprocessor means A then resetting microprocessor means B.
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Specification