Statistics signature generation and analysis

• US 6,484,288 B1
• Filed: 12/17/1999
• Issued: 11/19/2002
• Est. Priority Date: 12/17/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Harrison, Robert J., Hall, Christopher J., Bhandal, Amarjit S., Rowell, Anthony S.
• Primary Examiner(s): Baker, Stephen M.
• Application Number:
  US09/466,039
• Time in Patent Office: 1,068 Days
• Field of Search: 714/807
• US Class Current: 714/807
• CPC Class Codes: H03M 13/091 Parallel or block-wise CRC computation

Abstract

The present invention provides for a statistics Cyclic Redundancy Check (CRC) (108) wherein the statistics CRC (108) is representative of the values contained within a statistics RAM (110). The statistics CRC (108) is then used to reduce test vectors by allowing the validity of the statistics to be determined by reading this signature instead of reading all the individual statistics. The signature is regenerated for each complete pass of the statistics, and the contents of this register are only updated when the pass is complete.

Claims

1. A method of forming a Cyclic Redundancy Check (CRC) signature comprising the steps of:

a. forming a first input by generating the exclusive-or of bytes 0 and 2 of a first data string;

b. inputting the first input to a CRC generator;

c. inputting a second input from a CRC signature register to the CRC generator;

d. processing the first and second input in the CRC generator to generate a first output; and

e. outputting the first output to a low order byte of the CRC signature register.

2. The method of claim 1 wherein the CRC signature register is a rolling register.

3. The method of claim 1 wherein the method is repeated using subsequent bytes of the first data string to form the first input until all bytes of the first data string are used to form the CRC signature.

4. The method of claim 1 further comprising the steps of:

a. forming a third input by generating the exclusive-or of bytes 1 and 3 of the first data string;

b. inputting the third input to the CRC generator;

c. inputting a fourth input from the CRC signature register to the CRC generator;

d. processing the third and fourth input in the CRC generator to generate a second output; and

e. outputting the second output to a low order byte of the CRC signature register.

5. The method of claim 4 further comprising the steps of:

a. forming a fifth input by generating the exclusive-or of bytes 4 and 6 of the first data string;

b. inputting the fifth input to the CRC generator;

c. inputting a sixth input from the CRC signature register to the CRC generator;

d. processing the fifth and sixth input in the CRC generator to generate a third output; and

e. outputting the third output to a low order byte of the CRC signature register.

6. The method of claim 5 further comprising the steps of:

a. forming a seventh input by generating the exclusive-or of bytes 5 and 7 of the first data string;

b. inputting the seventh input to the CRC generator;

c. inputting an eighth input from the CRC signature register to the CRC generator;

d. processing the seventh and eighth input in the CRC generator to generate a fourth output; and

e. outputting the fourth output to a low order byte of the CRC signature register.

7. The method of claim 1 further comprising the step of storing the contents of the CRC signature register to a data storage device.

8. The method of claim 7 wherein the storing is done at predetermined intervals.

9. The method of claim 7 wherein a plurality of data strings are processed to form the CRC signature in the CRC signature register prior to storing the contents of the CRC signature register to the data storage device.

10. The method of claim 9 wherein the multiple data strings and the CRC signature are stored in a RAM.

11. The method of claim 10 wherein the plurality of data strings are statistical data.