Method and apparatus for analyzing integrated circuit operations

• US 7,577,930 B2
• Filed: 06/23/2005
• Issued: 08/18/2009
• Est. Priority Date: 06/23/2005
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Bailey, Robert L., Howard, Brian D.
• Primary Examiner(s): Chiang; Jack
• Assistant Examiner(s): Memula; Suresh
• Application Number:
  US11/165,862
• Publication Number:
  US 20060290400A1
• Time in Patent Office: 1,517 Days
• Field of Search: 716/6
• US Class Current: 716/113
• CPC Class Codes: G01R 31/318544 Scanning methods, algorithms and patterns G01R31/3183 takes precedence
• CPC Class Codes: G01R 31/318558 Addressing or selecting of subparts of the device under test

Abstract

A method and apparatus for viewing and/or analyzing the operations and logical states of an integrated circuit. The logical state of various flip-flops within the ASIC may be determined at a specified time. The embodiment may store these flip-flop states in a computer-readable data structure, such as a file or database. By repeating this process and incrementing or decrementing the time with each repetition, a more complete picture of the ASIC'"'"'s operation may be captured. Additionally, the embodiment may graphically display the flip-flop states, for example as a graph or waveform.

Claims

1. A method for outputting the operations of an integrated circuit, comprising the operations of:

reaching a trigger event occurring at a trigger time;

waiting a number of clock cycles after the occurrence of the trigger event;

reading a state of a last flip-flop of a set of flip-flops in a chain; and

determining if an additional read of the state of the last flip-flop is to be performed;

in response to determining no additional read of the state of the last-flip flop is to be performed, storing as data every state of the last flip-flop since a first read of the state of the last flip-flop;

linking each state of the last flip-flop stored as data to a unique one of the set of flip-flops in the chain; and

wherein the data is stored by a computer system in a waveform database that is computer-readable.

2. The method of claim 1, further comprising the operation of storing the state of the last flip-flop in a computer-readable medium.

3. The method of claim 1, further comprising the operation of freezing the state of all of the set of flip-flops after the operation of waiting a number of clock cycles after the occurrence of the trigger event.

4. The method of claim 3, further comprising the operation of incrementing a state from a next-to-last flip-flop in the chain to the last flip-flop in the chain.

5. The method of claim 4, wherein the operation of incrementing a state comprises:

discarding the state of the last flip-flop; and

passing the state of the next-to-last flip-flop to the last flip-flop.

6. The method of claim 5, further comprising the operation of:

in response to determining an additional read of the state of the last flip-flop is to be performed, performing operations a), b), c), and d) again.

7. The method of claim 6, further comprising the operation of:

using the waveform database that is computer-readable to generate a graphical output, the graphical output displaying a graph of the state of all flip-flops in the chain at a time equal to the trigger time plus the number of clock cycles.

8. The method of claim 1, further comprising:

determining whether an additional viewing of the operations of the integrated circuit is to be performed;

in the event an additional viewing of the operations of the integrated circuit is to be performed, incrementing the number of clock cycles by one; and

performing operations a), b), c), and d) again.

9. The method of claim 8, wherein the operation of incrementing a state comprises:

discarding the state of the last flip-flop; and

passing the state of the next-to-last flip-flop to the last flip-flop.

10. The method of claim 9, further comprising the operation of:

in response to determining an additional read of the state of the last flip-flop is to be performed, performing operations a), b), c), and d) a second time.

11. A computer-readable medium containing instructions which, when executed, perform the method of claim 10.

12. An apparatus configured to perform the method of claim 10.

13. The method of claim 10, further comprising the operations of:

in response to determining no additional read of the state of the last-flip flop is to be performed, storing as data every state of the last flip-flop since a first read of the state of the last flip-flop; and

linking each state of the last flip-flop stored as first data to a unique one of the set of flip-flops in the chain.

14. The method of claim 13, further comprising the operations of:

in response to incrementing the number of cycles and determining for a second time no additional read of the state of the last-flip flop is to be performed, storing as second data every state of the last flip-flop since a first read of the state of the last flip-flop and prior to incrementing the number of cycles; and

linking each state of the last flip-flop stored as second data to a unique one of the set of flip-flops in the chain.

15. The method of claim 14, further comprising the operation of creating a graphical display from the first and second data.

16. The method of claim 15, wherein the graphical display comprises:

a first frame corresponding to the first data; and

a second frame corresponding to the second data.

17. The method of claim 16, wherein the graphical display is non-static.

18. The method of claim 1, further comprising performing operations a) and b) during operation of the integrated circuit.

19. The method of claim 1, further comprising performing operations a), b), c), and d) in an operating environment of the integrated circuit.

20. The method of claim 1, wherein the integrated circuit is an application-specific integrated circuit.

21. The method of claim 20, wherein:

the integrated circuit comprises a logic block; and

operations a), b), c), and d) are executed on the logic block.

22. A method for outputting the operations of an integrated circuit, comprising the operations of:

reaching a trigger event occurring at a trigger time;

waiting a number of clock cycles after the occurrence of the trigger event;

freezing a state of each of a set of flip-flops;

reading the state of a last flip-flop of the set of flip-flops;

determining an additional read of the state of the last flip-flop is to be performed;

in response to determining no additional read of the state of the last-flip flop is to be performed, storing as data every state of the last flip-flop since a first read of the state of the last flip-flop;

linking each state of the last flip-flop stored as data to a unique one of the set of flip-flops in the chain; and

wherein the data is stored by a computer system in a waveform database that is computer-readable.