Method and apparatus for improved monitoring and detection of improper device operation

• US 4,773,028 A
• Filed: 10/01/1984
• Issued: 09/20/1988
• Est. Priority Date: 10/01/1984
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Tallman, James L.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Black, Thomas G.
• Application Number:
  US06/656,819
• Time in Patent Office: 1,450 Days
• Field of Search: 364/550, 364/551, 364/580, 364/578, 364/579, 364/149, 364/150, 364/151, 364/152, 364/801, 324/73 R, 324/73 A, 324/73 T, 340/515, 371/25, 371/20
• US Class Current: 714/736
• CPC Class Codes: G01R 31/3193 with comparison between actual response and known fault free response receiver details G01R31/31924
• CPC Class Codes: G01R 31/31935 Storing data, e.g. failure memory
• CPC Class Codes: G06F 11/261 by simulating additional hardware, e.g. fault simulation
• CPC Class Codes: G06F 11/3466 Performance evaluation by tracing or monitoring

Abstract

A method and apparatus is disclosed for the improved monitoring and detection of improper device operation. Operation of a prototype device is first modeled. In particular, a set of test vectors is selected to provide a desired degree of testing of the prototype unit. The expected response of the prototype to the selected set of test vectors is determined through the use of analytical prediction means, and stored for subsequent comparison with the operation of the prototype unit. Thereafter, the selected set of test vectors are applied to the prototype unit, and the response thereto compared in real time with the expected responses. Improper operation of the prototype device is thereby identified, and associate information recorded for subsequent analysis.

Claims

1. Apparatus for monitoring the operation of a device to detect improper operation thereof in response to the application of a series of test monitoring the operation of a device to detect improper operation thereof in response to the application of a series of test vectors applied thereto, said device generating information signals and operation signals in response to each applied test vector, said apparatus comprising:

predicting means for predicting correct operation of the device by generating expected information and operation signals in response to the application of the series of test vectors applied thereto;

comparing means responsive to the operation of the device and to said predicting means for comparing the operation signals of the device with the expected operation signals in response to the same test vector;

detection means responsive to said comparing means for detecting improper operation of the device; and

storage means coupled to said device and to said prediction means responsive to said detection means for storing information signals representative of the operation of the device and the expected operation signals for the same application of test vectors, said storage means includes;

first storage means coupled to the device responsive to

said detection means for storing information signals

descriptive of the operation of the device subsequent to the detection of improper operation of the device in response

to the corresponding operation and expected operation

signals; and

,

second storage means coupled to the predicting means

responsive to said detection means for storing expected information signals descriptive of the predicted correct

operation of the device subsequent to the detection of

improper operation of the device in response to the

corresponding operation and expected operation signals.

2. Apparatus as recited in claim 1 wherein said predicting means further comprises:

program means for modeling the operation of the device;

digital computer means for performing said program means so that the expected information and operation signals of the device is determined; and

,

prediction storage means responsive to said digital computer means for storing the expected information and operation signals of the device.

3. Apparatus as recited in claim 1, wherein said comparing means further comprises a plurality of single comparing means for comparing a single signal from the device with a corresponding single signal from said predicting means.

4. A method for monitoring the operation of a device to detect the improper operation thereof in response to the application of a series of test vectors applied thereto, said device generating information signals and operation signals in response to each applied test vector, said method comprising the steps of:

predicting the correct operation of the device by generating expected information and operation signals in response to the application of each of the series of test vectors;

repeatedly comparing the operation signals of the device with the expected operation signals to detect improper device operation in response to each of the test vectors;

detecting improper device operation by detecting comparison errors; and

repeatedly storing information signals representative of the operation of the device and expected information signals representative of the predicted correct operation of the device in response to the detection of improper device operation.

5. A method for monitoring the operation of a device to detect the improper operation thereof as in claim 4 further comprising the step of terminating the storing of information signals representative of the device and expected information signals in response to the detection of improper device operation.

6. Apparatus for monitoring digital information produced by a digital device, to detect improper operation thereof, comprising:

predicting means responsive to the digital device for producing digital expected information and operation signals representative of the digital information and operation signals expected to be produced by the digital device;

comparing means responsive to digital information signals produced by the digital device and to the expected digital information signals produced by said predicting means for detecting a difference therebetween;

detecting means responsive to said comparing means for producing a signal in response to the detection of a difference between the digital information signals produced by the digital device and the digital expected information signals produced by said predicting means;

storage means responsive to the signal produced by said detecting means, coupled to the digital device and to the predicting means for storing digital operation signals of the digital device and for storing digital expected operation signals produced by said predicting means.

7. Apparatus as recited in claim 6, wherein said predicting means further comprises

storage means for storing digital expected information and operation signals representative of the digital information expected to be produced by the digital device;

control means coupled to said storage means and responsive to said digital device for sequentially extracting from said storage means the digital expected information and operation signals expected to be produced by the digital device.

8. Apparatus as recited in claim 6, wherein said predicting means comprises:

determining means for producing the digital expected information and operation signals expected to be produced by the digital device;

counter means responsive to the digital device for producing a cyclic sequence of binary numbers;

memory means coupled to said counter means for storing and reproducing the digital expected information and operation signals expected to be produced by the digital device; and

,

control means responsive to the digital device and said counter means for storing in and extracting from said memory means the digital expected information and operation signals expected to be produced by the digital device.

9. Apparatus as recited in claim 6, wherein said comparing means further comprises a plurality of comparing devices, each of which comparing devices compares a single first signal with a single second signal, and produces an output signal if the first signal does not agree with the second signal.

10. Apparatus as recited in claim 9, wherein said comparing device is an EXCLUSIVE-OR gate.

11. Apparatus as recited in claim 9, wherein said detecting means further comprises an OR gate having a plurality of inputs thereto, with each input coupled to the output of one of the plurality of comparing devices.

12. Apparatus as recited in claim 6, wherein said storage means further comprises means for storing digital operation signals of the digital device and for storing digital expected operation signals produced by said predicting means in response to the signal produced by said detecting means.

13. Apparatus as recited in claim 6, wherein said storage means further comprises means for continuously storing digital operation signals of the digital device and for continuously storing digital expected operation signals produced by said predicting means, and terminates the storing of said operation signals in response to the signal produced by said detecting means.

14. Apparatus as recited in claim 6, wherein said storage means further comprises:

counter means coupled to the digital device for producing a binary count;

digital storage means coupled to the digital device, the predicting means and said counter means for storing digital operation signals of the digital device and for storing digital expected operation signals produced by said predicting means; and

control means coupled to said counter means and responsive to said detection means for controlling the counting of said counter means.

15. Apparatus as recited in claim 14, wherein said control means further comprises means for inhibiting the operation of said counter means responsive to a preselected binary count being produced by said counting means.

16. Apparatus as recited in claim 14, wherein said control means further comprises means for inhibiting the operation of said counter means responsive to the signal produced by said detecting means.

17. A method for testing the proper performance of a device, said method comprising the steps of:

applying test criteria to a simulator of the device for producing expected information and operation signals therefrom;

applying at least on of the test criteria applied to the simulator to the device to be tested for producing at least one set of information and operation signals therefrom;

comparing the expected operation signals from the simulator with the operation signals from the device to the same test criteria to detect errors in the performance of the device; and

repeatedly storing information signals of the device and the expected information signals from the simulator when an error is detected in the comparing step.

18. A method for testing the proper performance of a device as in claim 17 wherein the performance comparing step includes the step of terminating the testing when at least one of the responses from the device does not compare with the expected responses from the simulator.

19. Apparatus for testing the proper performance of a device comprising:

a simulator means for modeling the desired performance of the device;

first means for applying test criteria to the simulator means for producing expected information and operation signals therefrom;

second means for applying at least one of the test criteria applied to the simulation means to the device to be tested for producing at least one set of information and operation signals therefrom;

third means for comparing the expected operation signals from the simulator means with the operation signals from the device to the same test criteria to detect errors in the performance of the device; and

means for repeatedly storing information signals of the device and the expected information signals from the simulator means when when an error is detected by the third means.

20. Apparatus for testing the proper performance of a device as in claim 19 wherein the third means includes means for terminating the testing when at least on of the operation signals from the device does not compare with the expected information signals from the simulator means.

21. Apparatus for monitoring the operation of a device to detect improper operation thereof in response to the application of a series of test vectors applied thereto, comprising:

predicting means for predicting expected information and operation signals of the device in response to the application of the series of test vectors applied thereto;

comparing means responsive to the operation signals of the device and to said expected operation signals of the predicting means for comparing the operation of the device with the predicted correct operation in response to the same test vector;

detection means responsive to said comparing means for detecting improper operation of the device; and

storage means coupled to said device and to said predicting means responsive to said detection means for storing information signals of the device and the expected information signals, said storage means includes;

first storage means coupled to the device and responsive to said detection means for storing information signals of the device prior to the detection of improper operation of the device; and

second storage means coupled to the predicting means and responsive to said detection means for storing expected information signals prior to the detection of improper operation of the device.