Hardware interlock mechanism using a watchdog timer
First Claim
1. An integrated circuit, comprising:
- a watchdog timer coupled to receive a reset input upon a predetermined change in a system state, wherein the watchdog timer is further configured to provide an indication in response to an expiration of the watchdog timer; and
logic configured to receive a request for a system reset, wherein the logic is configured to query the watchdog timer for the expiration of the watchdog timer in response to receiving the request for the system reset.
2 Assignments
0 Petitions
Accused Products
Abstract
An integrated circuit, a client computer system, and a method for using a watchdog timer as a check before changing the system state of a computer system. The integrated circuit includes a first bus interface logic for coupling to a first external bus, a watchdog timer, and logic configured to receive a request for a system reset. The watchdog timer is coupled to receive a reset input upon a predetermined change in a system state. The watchdog timer is further configured to provide an indication in response to an expiration of the watchdog timer. The logic is configured to query the watchdog timer for the expiration of the watchdog timer in response to receiving the request for the system reset.
28 Citations
68 Claims
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1. An integrated circuit, comprising:
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a watchdog timer coupled to receive a reset input upon a predetermined change in a system state, wherein the watchdog timer is further configured to provide an indication in response to an expiration of the watchdog timer; and
logic configured to receive a request for a system reset, wherein the logic is configured to query the watchdog timer for the expiration of the watchdog timer in response to receiving the request for the system reset. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An integrated circuit, comprising:
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a timing means coupled to receive a reset input upon a predetermined change in a system state, wherein the timing means is further configured to provide an indication in response to an expiration of the timing means; and
logic means configured to receive a request for a system reset, wherein the logic means is configured to query the timing means for the expiration of the timing means in response to receiving the request for the system reset. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A computer system, comprising:
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a first external bus; and
an integrated circuit, the integrated circuit comprising;
a first bus interface logic for coupling to the first external bus;
a watchdog timer coupled to receive a reset input upon a predetermined change in a system state, wherein the watchdog timer is further configured to provide an indication in response to an expiration of the watchdog timer; and
logic configured to receive a request for a system reset, wherein the logic is configured to query the watchdog timer for the expiration of the watchdog timer in response to receiving the request for the system reset. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. A computer system, comprising:
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a first external communications means; and
an integrated circuit, the integrated circuit comprising;
a first interface means for coupling to the first external communications means;
a timing means coupled to receive a reset input upon a predetermined change in a system state, wherein the timing means is further configured to provide an indication in response to an expiration of the timing means; and
logic means configured to receive a request for a system reset, wherein the logic means is configured to query the timing means for the expiration of the timing means in response to receiving the request for the system reset. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A method of operating a computer system, the method comprising:
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receiving a request for a system state change;
checking for status of a watchdog timer;
denying the request for the system state change if the watchdog timer has not expired; and
performing the request for the system state change if the watchdog timer has expired. - View Dependent Claims (55, 56, 57, 58)
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59. A method of operating a computer system, the method comprising the steps of:
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receiving a request for a system state change;
checking for status of a watchdog timer;
denying the request for the system state change if the watchdog timer has not expired; and
performing the request for the system state change if the watchdog timer has expired. - View Dependent Claims (60, 61, 62, 63)
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64. A computer readable medium encoded with instructions that, when executed by a computer system, performs a method for operating the client computer system, the method comprising:
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receiving a request for a system state change;
checking for status of a watchdog timer;
denying the request for the system state change if the watchdog timer has not expired; and
performing the request for the system state change if the watchdog timer has expired. - View Dependent Claims (65, 66, 67, 68)
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Specification