METHOD AND DEVICE FOR PROTECTING INFORMATION CONTAINED IN AN INTEGRATED CIRCUIT
First Claim
1. A method of protecting information contained in an integrated circuit (IC) from being revealed unless or until the information is changed or otherwise deemed safe for access, the integrated circuit having a test controller state machine (TCSM) directly or indirectly coupled to control structure and/or input and/or output of at least one data storage device, the at least one data storage device having information stored therein and the IC having at least one normal functional mode of operation and at least one testing mode of operation, comprising the steps of:
- (a) coupling, directly or indirectly, the TCSM with the integrated circuit to control and/or observe test structures of the integrated circuit,(b) causing the TCSM upon a request to test the integrated circuit to enter an erase mode, and(c) performing during the erase mode, either individually, sequentially, or concurrently, one or more of the following steps;
(1) activating a built in self-test (BIST) on one or more of the data storage devices until the information in the data storage device has been deemed safe for access, and/or (2) changing the information in one or more of the data storage device until the information in the data storage device has been deemed safe for access, and/or (3) changing the information contained in any scan cells of the integrated circuit until any information in the scan cells has been erased or deemed safe for access.
2 Assignments
0 Petitions
Accused Products
Abstract
An integrated circuit and a method of protection of an integrated circuit provides for a test controller state machine (TCSM) to be coupled to a control structure and/or an input and/or an output of at least one data storage device of the integrated circuit. The TCSM monitors the state of the data storage device and, upon a test request to the integrated circuit, causes the information in the data storage device to be changed or blocked until the data storage device is deemed safe for access. Such an integrated circuit and method protects information contained in data storage devices of the integrated circuit from being revealed during testing of circuitry of the integrated circuit.
13 Citations
28 Claims
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1. A method of protecting information contained in an integrated circuit (IC) from being revealed unless or until the information is changed or otherwise deemed safe for access, the integrated circuit having a test controller state machine (TCSM) directly or indirectly coupled to control structure and/or input and/or output of at least one data storage device, the at least one data storage device having information stored therein and the IC having at least one normal functional mode of operation and at least one testing mode of operation, comprising the steps of:
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(a) coupling, directly or indirectly, the TCSM with the integrated circuit to control and/or observe test structures of the integrated circuit, (b) causing the TCSM upon a request to test the integrated circuit to enter an erase mode, and (c) performing during the erase mode, either individually, sequentially, or concurrently, one or more of the following steps;
(1) activating a built in self-test (BIST) on one or more of the data storage devices until the information in the data storage device has been deemed safe for access, and/or (2) changing the information in one or more of the data storage device until the information in the data storage device has been deemed safe for access, and/or (3) changing the information contained in any scan cells of the integrated circuit until any information in the scan cells has been erased or deemed safe for access. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An integrated circuit comprising:
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(a) at least one data storage device wherein said data storage device has information stored therein and the integrated circuit has at least one normal functional mode of operation and at least one testing mode of operation, and (b) a test controller state machine (TCSM) directly or indirectly coupled to at least one data storage device wherein the TCSM includes implementation means for causing the information in the at least one data storage device to be protected from outside access unless or until the at least one data storage device is deemed safe for access. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification