SAFE SCHEDULER FOR FINITE STATE DETERMINISTIC APPLICATION
First Claim
1. An embedded controller, comprising:
- a functional logic module interface;
a task scheduler module arranged to schedule a finite number of events of one or more functional logic modules accessible via the functional logic module interface; and
a safety module, the safety module arranged to;
monitor the finite number of events;
incrementally create a mathematic check value, each increment based on at least one of the finite number of monitored events;
compare the mathematic check value to a pre-computed model check value; and
set a test result value based on the comparison.
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Accused Products
Abstract
A safety system monitors faults in an embedded control system. The embedded control system is modeled to produce one or more model check values by calculating how many clock cycles will pass between an initialization time point and at least one event time point for a specific event. The initialization time point is a certain point in an initialization function of a scheduler in the embedded control system. The at least one event time point is an expected number of clock cycles to pass before a specific event occurs. In operation, the embedded control system is initialized, a current clock cycle counter value is retrieved at a certain point in the initialization, and either an occurrence or an absence of an occurrence of a scheduled event is recognized. A current clock cycle value is recorded upon the recognition, and a mathematic check value is produced from the clock cycle value stored at the certain point in the initialization and the clock cycle value recorded upon the recognition. Subsequently, the model check value is compared to the mathematic check value, and action is taken based on the comparison.
16 Citations
20 Claims
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1. An embedded controller, comprising:
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a functional logic module interface; a task scheduler module arranged to schedule a finite number of events of one or more functional logic modules accessible via the functional logic module interface; and a safety module, the safety module arranged to; monitor the finite number of events; incrementally create a mathematic check value, each increment based on at least one of the finite number of monitored events; compare the mathematic check value to a pre-computed model check value; and set a test result value based on the comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A safety system method to monitor faults in an embedded control system, comprising:
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modeling the embedded control system to produce one or more model check values, the modeling including calculating how many clock cycles will pass between an initialization time point and at least one event time point, the initialization time point being a certain point in an initialization function of a scheduler in the embedded control system, the at least one event time point being an expected number of clock cycles to pass before an event occurs; initializing the embedded control system; storing a current clock cycle counter value at a certain point in the initialization; recognizing an occurrence or absence of occurrence of a scheduled event; recording a current clock cycle value upon the recognition; and producing a mathematic check value from the clock cycle value stored at the certain point in the initialization and the clock cycle value recorded upon the recognition; comparing the model check value to the mathematic check value; and taking an action based on the comparison. - View Dependent Claims (12, 13, 14, 15)
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16. A non-transitory computer readable medium having computer executable instructions thereon that, when executed, cause a processor to monitor an expected behavior of an embedded control system, the monitoring including acts comprising:
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storing a model check value, the model check value based on a plurality of model time stamps, each model time stamp representing a value of a counter taken at a certain point in a model of a finite state machine arranged to direct operations of a system under control; initializing the embedded control system; executing a plurality of tasks, the tasks directed by the finite state machine; storing a plurality of time stamps associated with an actual behavior of the embedded control system; calculating a mathematic check value using at least some of the stored plurality of time stamps; comparing the mathematic check value with the model check value; and directing an action in the embedded control system based on the comparison. - View Dependent Claims (17, 18, 19, 20)
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Specification