Diagnostic system for a watchdog timer
First Claim
1. A testing system for a watchdog timer monitoring a programmed processor and associated with a system which is controlled by a control program executed by the programmed processor and which is monitored by a supervisory system with the watchdog timer generating an interruption signal which interrupts execution of the control program when the watchdog timer does not generate a reset comprising:
- means contained in the supervisory system coupled to the watchdog timer for initiating testing of the watchdog timer; and
means contained in the watchdog timer for disabling the generation of the interruption signal during testing of the watchdog timer.
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Accused Products
Abstract
A system (10) is disclosed for testing a watchdog timer (22). The watchdog timer is associated with a system (14) which is controlled by a control program executed by a programmed processor (20) and which is monitored by a supervisory system (18) in which the watchdog timer generates an interruption signal (NMI) which interrupts the control program when the watchdog timer does not generate a reset signal within a time window measured from a last reset signal. The supervisory system contains a circuit coupled to the watchdog timer for initiating testing of the watchdog timer. The watchdog timer contains a circuit for disabling the generation of the interruption signal during testing of the watchdog timer. Furthermore, the watchdog timer contains a circuit for shutting down the system which is controlled by the control program when the control program does not resume normal operation in response to an interruption signal. The watchdog timer has a circuit for disabling the circuit for shutting down the system which is controlled by the control program during testing of the watchdog timer.
62 Citations
24 Claims
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1. A testing system for a watchdog timer monitoring a programmed processor and associated with a system which is controlled by a control program executed by the programmed processor and which is monitored by a supervisory system with the watchdog timer generating an interruption signal which interrupts execution of the control program when the watchdog timer does not generate a reset comprising:
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means contained in the supervisory system coupled to the watchdog timer for initiating testing of the watchdog timer; and means contained in the watchdog timer for disabling the generation of the interruption signal during testing of the watchdog timer. - View Dependent Claims (2, 4, 5, 6, 7, 8)
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3. A testing system for a watchdog timer monitoring a programmed processor and associated with a system which is controlled by a control program executed by the programmed processor and which is monitored by a supervisory system with the watchdog timer generating an interruption signal which interrupts execution of the control program when the watchdog timer does not generate a reset comprising:
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means contained in the supervisory system coupled to the watchdog timer for initiating testing of the watchdog timer; and means contained in the watchdog timer for disabling the generation of the interruption signal during testing of the watchdog timer; wherein the watchdog timer further comprises; means for shutting down the system which is controlled by the control program when the control program does not resume normal operation in response to an interruption signal; and
whereinthe watchdog timer has means for disabling the means for shutting down the system which is controlled by the control program during testing of the watchdog timer.
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9. A testing system for a watchdog timer monitoring a programmed processor and associated with a system which is controlled by a control program executed by the programmed processor and which is monitored by a supervisory system with the watchdog timer generating an interruption signal which interrupts execution of the control program when the watchdog timer does not generate a reset comprising:
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means contained in the supervisory system coupled to the watchdog timer for initiating testing of the watchdog timer; means contained in the watchdog timer for disabling the generation of the interruption signal during testing of the watchdog timer; and means coupling the watchdog timer to the supervisory system for transmitting a signal representing results of the testing of the watchdog timer to the supervisory system; wherein the watchdog timer comprises a decoder, coupled to the programmed processor, for decoding words transmitted from the programmed processor which generates a reset of the watchdog timer in response to decoding a predetermined sequence of words and which is coupled to the means for transmitting a signal to the supervisory system in response to decoding the predetermined sequence of words. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A testing system for a watchdog timer monitoring a programmed processor and associated with a system which is controlled by a control program executed by the programmed processor and which is monitored by a supervisory system with the watchdog timer generating an interruption signal which interrupts execution of the control program when the watchdog timer does not generate a reset comprising:
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means contained in the supervisory system coupled to the watchdog timer for initiating testing of the watchdog timer; and means contained in the watchdog timer for disabling the generation of the interruption signal during testing of the watchdog timer; wherein the system which is controlled by the control program is an electrical power generator in an airframe. - View Dependent Claims (20)
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21. A testing system for a watchdog timer which monitors the operation of a programmed processor with the watchdog timer having means for generating an interruption signal to interrupt execution of a program by the programmed processor comprising:
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means, coupled to the watchdog timer, for initiating testing of the watchdog timer; and means for disabling generation of the interruption signal by the means for generating the interruption signal during testing of the watchdog timer.
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22. A testing system for a watchdog timer which monitors the operation of a programmed processor with the watchdog timer having means for generating an interruption signal to interrupt execution of a program by the programmed processor comprising:
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means, coupled to the watchdog timer, for initiating testing of the watchdog timer; means for disabling generation of the interruption signal by the means for generating the interruption signal during testing of the watchdog timer; a system which is controlled by the program executed by the programmed processor; and means for shutting down the system which is controlled by the program when the program does not resume normal operation in response to an interruption signal;
wherein;the watchdog timer has means for disabling the means for shutting down the system which is controlled by the program during testing of the watchdog timer.
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23. In a system including a watchdog timer and a programmed processor, a method of monitoring the programmed processor comprising the steps:
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transmitting a signal from the programmed processor to the watchdog timer; generating an interruption signal in the watchdog timer when the transmitted signal indicates that the programmed processor is not operating normally, said interruption signal interrupting execution of a program by the programmed processor; initiating testing of the watchdog timer; and disabling generation of the interruption signal by the watchdog timer during the testing of the watchdog timer so that during the testing the watchdog timer does not generate an interruption signal even if the transmitted signal indicates that the programmed processor is not operating normally. - View Dependent Claims (24)
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Specification