Granted Patent B2

US 7,861,200 · App. 12/054,015 · Granted Dec 28, 2010

Abstract

Claims (57)

1. A method comprising:

receiving at a processor a first weight associated with a goal function having an adjustable goal function value, the first weight indicating a relative importance of a hold time of a device under test;

receiving at the processor a second weight associated with the goal function, the second weight indicating a relative importance of a setup time of the device under test, the goal function comprising a sum of the first weight times the hold time and the second weight times the setup time; and

determining at the processor a minimum value for the goal function by iteratively adjusting the goal function value and testing the device under test based on the goal function value.

2. The method of claim 1 , further comprising:

determining a minimum timing parameter value associated with the minimum goal function value, wherein the minimum timing parameter value is associated with one of the hold time and the setup time of the device under test.

3. The method of claim 1 , wherein determining the minimum value for the goal function comprises:

iteratively adjusting the goal function value by a first step size;

applying an input to the device under test having a setup and hold time based on the goal function value;

in response to determining that an output of the device under test based on the input does not match a specified output, adjusting a magnitude of the first step size.

4. The method of claim 3 , wherein determining the minimum value of the goal function further comprises determining the minimum value based on the magnitude of the first step size.

5. The method of claim 3 , wherein determining the minimum value for the goal function further comprises:

iteratively adjusting a timing parameter value associated with the goal function value by a second step size, wherein the timing parameter value is associated with one of the setup time and the hold time associated with the device under test; and

in response to determining that the output of the device under test based on the input does not match the specified output, adjusting a magnitude of the second step size.

6. The method of claim 5 , wherein determining the minimum value for the goal function further comprises determining the minimum value based on the magnitude of the first step size and the magnitude of the second step size.

7. The method of claim 1 , wherein determining the minimum value for the goal function comprises:

associating a timing parameter with one of the hold time and the setup time of the device under test;

determining a goal function value;

determining a timing parameter value associated with the timing parameter;

until a first step size is less than a first value and a second step size is less than a second value:

adjusting the timing parameter value by the first step size;

until a test result indicates a failed test:

iteratively adjusting the goal function value by the second step size;

testing the device under test based on the goal function value to produce the test result; and

setting a first indicator and storing the goal function value and the timing parameter value in response to the test result indicating a passed test; and

in response to the test result indicating a failed test:

in response to determining the first indicator is set, setting the timing parameter value to the stored timing parameter value, setting the goal function value to the stored goal function value, and clearing the first indicator; and

in response to determining the first indicator is not set, adjusting one of the first step size and the second step size; and

storing the goal function value in response to the first step size being less than the first value and the second step size being less than the second value, the stored goal function value representative of a minimum goal function value for the device under test.

8. The method of claim 7 , wherein associating the timing parameter comprises associating the timing parameter with the hold time in response to determining the first weight is greater than the second weight, and wherein determining the timing parameter value comprises:

setting a first hold time value to an initial value;

determining a first setup time value based on the first hold time value;

adjusting the first setup time value to determine a second setup time value; and

determining the timing parameter value based on the second setup time value.

9. The method of claim 8 , wherein determining the first setup time value comprises determining the first setup time value based on a binary search, the binary search based on the first hold time value.

10. The method of claim 9 , wherein determining the timing parameter value time comprises determining the timing parameter value based on a binary search, the binary search based on the second setup time value.

11. The method of claim 7 , wherein associating the timing parameter comprises associating the timing parameter with the setup time in response to determining the first weight is less than the second weight, and wherein determining the timing parameter value comprises:

setting a first setup time value to an initial value;

determining a first hold time value based on the first setup time value;

adjusting the first hold time value to determine a second hold time value; and

determining the timing parameter value based on the second hold time value.

12. The method of claim 11 , wherein determining the first hold time value comprises determining the first hold time value based on a binary search, the binary search based on the first setup time value.

13. The method of claim 11 , wherein determining the timing parameter value time comprises determining the timing parameter value based on a binary search, the binary search based on the second hold time value.

14. The method of claim 7 , wherein adjusting the timing parameter value comprises adding the first step size to the timing parameter value.

15. The method of claim 7 , wherein adjusting the timing parameter value comprises subtracting the first step size from the timing parameter value.

16. The method of claim 1 , further comprising:

designing an integrated circuit device based on the minimum value for the goal function to produce an integrated circuit design.

17. The method of claim 16 , further comprising forming an integrated circuit based on the integrated circuit design.

18. A computer readable medium storing a computer program comprising instructions to manipulate a processor, the instructions comprising instructions to:

receive a first weight associated with a goal function having an adjustable goal function value, the first weight indicating a relative importance of a hold time of a device under test;

receive a second weight associated with the goal function, the second weight indicating a relative importance of a setup time of the device under test, the goal function comprising a sum of the first weight times the hold time and the second weight times the setup time;

determine a minimum value for the goal function by iteratively adjusting the goal function value and testing the device under test based on the goal function value.

19. The computer readable medium of claim 18 , wherein the instructions further comprise instructions to determine a minimum timing parameter value associated with the minimum goal function value, wherein the minimum timing parameter is one of a hold time and a setup time associated with the device under test.

20. The computer readable medium of claim 18 , wherein the instructions to determine the minimum value for the goal function comprise instructions to:

iteratively adjust a goal function value by a first step size;

apply an input to the device under test having a setup and hold time associated with the goal function value;

in response to determining that an output of the device under test based on the input does not match a specified output, adjust a magnitude of the first step size.

Assignments (31)