Source synchronous link integrity validation

• US 6,965,648 B1
• Filed: 05/04/2000
• Issued: 11/15/2005
• Est. Priority Date: 05/04/2000
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Chakrabarti, Prabhansu, Smith, Brian L.
• Primary Examiner(s): Ghebretinsae, Temesghen
• Assistant Examiner(s): Ahn, Sam K.
• Application Number:
  US09/565,193
• Time in Patent Office: 2,021 Days
• Field of Search: 375/257, 375219-222, 375/239, 375/356, 375/364, 375/360, 375/242, 375/252, 375/237, 375/287, 375/224, 375/225, 375/226, 375/227, 375/228, 702/79, 702/110, 370/282
• US Class Current: 375/257
• CPC Class Codes: G01R 31/3185 Reconfiguring for testing, e.g. LSSD, partitioning
• CPC Class Codes: G06F 11/221 to test buses, lines or interfaces, e.g. stuck-at or open line faults
• CPC Class Codes: H04L 1/242 by comparing a transmitted test signal with a locally generated replica

Abstract

A system may perform interconnect BIST (IBIST) testing on source synchronous links. The system may perform, at normal operating frequency, a source synchronous link test that tests a victim line on the source synchronous link using a transition weave pattern. The transition weave pattern causes interaction between a data transition on the victim line, previous transitions on the victim line, and transitions on the other lines of the link (the “aggressor” lines). The interaction caused may be: (i) a first crossing pulse on the victim line; (ii) a second crossing pulse of the opposite polarity on each aggressor line concurrent with the first crossing pulse on the victim line; and (iii) a reflection in the opposite direction of the first transition of the first crossing pulse, wherein the reflection results from a previous transition on the victim line.

Claims

1. A method comprising:

generating a first transition on a first line of a source synchronous link to cause a first reflection on said first line;

subsequently generating a first crossing pulse on said first line and generating a second crossing pulse on a second line of said source synchronous link, said generating said second crossing pulse performed concurrent with said generating said first crossing pulse, said second crossing pulse having an opposite polarity of said first crossing pulse;

receiving said first crossing pulse and said second crossing pulse in a receiving circuit coupled to said first line and to said second line

generating a third crossing pulse on said first line;

generating a fourth crossing pulse on said second line, said generating said fourth crossing pulse performed concurrent with said generating said third crossing pulse, said fourth crossing pulse having a same polarity as said third crossing pulse; and

verifying that signals on said first line and said second line are correctly received in said receiving circuit.

2. The method as recited in claim 1 wherein said source synchronous link includes one or more additional lines, the method further comprising generating a fifth crossing pulse on each of said one or more additional lines concurrently with said generating said first crossing pulse and said generating said second crossing pulse, said fifth crossing pulse having said opposite polarity of said first crossing pulse.

3. The method as recited in claim 1 wherein said first transition occurs from a first binary state to a second binary state on said first line.

4. The method as recited in claim 3 wherein said generating said first crossing pulse comprises generating a transition from said second binary state to said first binary state and subsequently generating a transition from said second binary state to said first binary state.

5. The method as recited in claim 1 further comprising:

generating a second transition on said first line to cause a second reflection on said first line subsequent to said generating said first crossing pulse; and

subsequently generating a fifth crossing pulse on said first line, wherein said fifth crossing pulse has said opposite polarity of said first crossing pulse.

6. The method as recited in claim 5 further comprising generating a sixth crossing pulse on said second line, said generating said sixth crossing pulse performed concurrent with said generating said fifth crossing pulse, and said sixth crossing pulse having an opposite polarity of said fifth crossing pulse.

7. The method as recited in claim 1 wherein said source synchronous link includes a clock line, and wherein a transfer on said source synchronous link occurs on each edge of said clock signal, and wherein said first crossing pulse occurs on a first one of a rising edge or a falling edge of said clock signal, the method further comprising:

generating a fifth crossing pulse on said first line on the other one of said rising edge or said falling edge of said clock signal; and

generating a sixth crossing pulse on said second line concurrent with said generating said fifth crossing pulse.

8. The method as recited in claim 1 further comprising:

generating a second transition on said second line to cause a second reflection on said second line subsequent to said generating said first crossing pulse; and

subsequently generating a fifth crossing pulse on said second line and generating a sixth crossing pulse on said first line, said generating said sixth crossing pulse performed concurrent with said generating said fifth crossing pulse, said sixth crossing pulse having an opposite polarity of said fifth crossing pulse.

9. The method as recited in claim 1 further comprising:

generating a fifth crossing pulse on said first line; and

generating a sixth crossing pulse on said second line, said generating said sixth crossing pulse performed one data transfer prior to said generating said fifth crossing pulse, said sixth crossing pulse having an opposite polarity of said fifth crossing pulse.

10. A method comprising:

generating a first transition on a first line of a source synchronous link to cause a first reflection on said first line;

subsequently generating a first crossing pulse on said first line and generating a second crossing pulse on a second line of said source synchronous link, said generating said second crossing pulse performed concurrent with said generating said first crossing pulse, said second crossing pulse having an opposite polarity of said first crossing pulse;

receiving said first crossing pulse and said second crossing pulse in a receiving circuit coupled to said first line and to said second line;

generating a second transition on said first line to cause a second reflection on said first line subsequent to said generating said first crossing pulse;

subsequently generating a third crossing pulse on said first line, wherein a first number of data transfers on said first line between said first reflection and said first crossing pulse differs from a second number of data transfers on said first line between said second reflection and said third crossing pulse; and

verifying that signals on said first line and said second line are correctly received in said receiving circuit.

11. The method as recited in claim 10 further comprising generating a fourth crossing pulse on said second line, said generating said fourth crossing pulse performed concurrent with said generating said third crossing pulse, and said fourth crossing pulse having an opposite polarity of said third crossing pulse.

12. A system comprising:

a source synchronous link including at least a first line and a second line;

a first circuit coupled to transmit on said source synchronous link;

a second circuit coupled to receive on said source synchronous link;

wherein said first circuit is configured to transmit a first transition for generating a first reflection on said first line and to transmit a subsequent first crossing pulse on said first line, and wherein said first circuit is configured to transmit a second crossing pulse on said second line, said second crossing pulse transmitted concurrent with said first crossing pulse and having an opposite polarity of said first crossing pulse, and wherein said second circuit is configured to verify that signals on said first line and said second line are correctly received;

a second source synchronous link including at least a third line and a fourth line;

a third circuit coupled to transmit on said second source synchronous link;

a fourth circuit coupled to receive on said second source synchronous link; and

wherein said third circuit is configured to transmit a second transition for generating a second reflection on said third line and to transmit a subsequent third crossing pulse on said first line, and wherein said third circuit is configured to transmit a fourth crossing pulse on said fourth line, said fourth crossing pulse transmitted concurrent with said third crossing pulse and having an opposite polarity of said third crossing pulse, and wherein said fourth circuit is configured to receive said fourth crossing pulse and to verify that said fourth crossing pulse is correctly received.

13. The system as recited in claim 12 wherein said source synchronous link includes one or more additional lines, and wherein said first circuit is configured to transmit a fifth crossing pulse on each of said one or more additional lines concurrent with said first crossing pulse on said first line and said second crossing pulse on said second line, said fifth crossing pulse having said opposite polarity of said first crossing pulse.

14. The system as recited in claim 12 wherein said first circuit is further configured to transmit a third transition to cause a third reflection on said first line subsequent to said first crossing pulse, and wherein said first circuit is further configured to subsequently transmit a fifth crossing pulse on said first line, wherein said fifth crossing pulse has said opposite polarity of said first crossing pulse.

15. The system as recited in claim 14 wherein said first circuit is further configured to transmit a sixth crossing pulse on said second line concurrent with said fifth crossing pulse, and said sixth crossing pulse having an opposite polarity of said fifth crossing pulse.

16. The system method as recited in claim 12 wherein said source synchronous link includes a clock line, and wherein a transfer on said source synchronous link occurs on each edge of said clock signal, and wherein said first crossing pulse occurs on a first one of a rising edge or a falling edge of said clock signal, and wherein said first circuit is further configured to transmit a fifth crossing pulse on said first line on the other one of said rising edge or said falling edge of said clock signal, and wherein said first circuit is further configured to transmit a sixth crossing pulse on said second line concurrent with said fifth crossing pulse.

17. The system as recited in claim 12 wherein said first circuit is further configured to transmit a third transition on said second line to generate a third reflection subsequent to said generating said first crossing pulse, and wherein said first circuit is further configured to transmit a fifth crossing pulse on said second line and a sixth crossing pulse on said first line, said sixth crossing pulse transmitted concurrent with said fifth crossing pulse, said sixth crossing pulse having an opposite polarity of said fifth crossing pulse.

18. The system as recited in claim 12 further comprising one or more error registers, wherein said second circuit is configured to report an error if said first crossing pulse is not correctly received in said second circuit, and wherein said error is logged in said one or more error registers.

19. The system as recited in claim 12 wherein the first circuit is further configured to transmit a fifth crossing pulse on said first line and to concurrently transmit a sixth crossing pulse on said second line, said sixth crossing pulse having a same polarity as said fifth crossing pulse.

20. The system as recited in claim 12 wherein the first circuit is further configured to transmit a fifth crossing pulse on said first line and to transmit a sixth crossing pulse on said second line one data transfer prior to transmitting said fifth crossing pulse, said sixth crossing pulse having an opposite polarity of said fifth crossing pulse.

21. A system comprising:

a source synchronous link including at least a first line and a second line;

a first circuit coupled to transmit on said source synchronous link; and

a second circuit coupled to receive on said source synchronous link;

wherein said first circuit is configured to transmit a first transition for generating a first reflection on said first line and to transmit a subsequent first crossing pulse on said first line, and wherein said first circuit is configured to transmit a second crossing pulse on said second line, said second crossing pulse transmitted concurrent with said first crossing pulse and having an opposite polarity of said first crossing pulse, and wherein said second circuit is configured to verify that signals on said first line and said second line are correctly received; and

wherein said first circuit is further configured to transmit a second transition for generating a second reflection on said first line subsequent to transmitting said first crossing pulse, and wherein said first circuit is further configured to transmit a third crossing pulse on said first line, wherein a first number of data transfers on said first line between said first transition and said first crossing pulse differs from a second number of data transfers on said first line between said second transition and said third crossing pulse.