Interface for bridging out-of-band information from a downstream communication link to an upstream communication link

• US 8,332,563 B2
• Filed: 03/31/2010
• Issued: 12/11/2012
• Est. Priority Date: 12/15/2004
• Status: Active Grant

• Current Assignee: Rambus Inc.
• Original Assignee: Rambus Inc.
• Inventors: Sobelman, Michael J.
• Primary Examiner(s): Myers, Paul R
• Assistant Examiner(s): Vu, Trisha
• Application Number:
  US12/752,010
• Publication Number:
  US 20110022750A1
• Time in Patent Office: 986 Days
• Field of Search: 710/105, 710/305, 710/100, 710/313, 710/314, 710/306, 714/48, 714/799, 370/467, 375219-220
• US Class Current: 710/305
• CPC Class Codes: G06F 13/4027 using bus bridges G06F13/4022 takes precedence
• CPC Class Codes: G06F 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247
• CPC Class Codes: G06F 13/4286 using a handshaking protocol, e.g. RS232C link
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H04L 25/0262 Arrangements for detecting the data rate of an incoming signal
• CPC Class Codes: H04L 25/4908 using mBnB codes

Abstract

A device includes a first interface to receive a signal from a first communication link, wherein the receive signal includes out-of-band (OOB) information. A detector coupled to the first interface detects the OOB information. An encoder coupled to the detector encodes the OOB information into one or more symbols (e.g., control characters). A second interface is coupled to the encoder and a second communication link (e.g., a serial transport path). The second interface transmits the symbols on the second communication link. The device also includes mechanisms for preventing false presence detection of terminating devices.

Claims

1. An intermediate device for use in a signaling system having an upstream device and plural terminating devices, the intermediate device comprising:

a set of first interfaces, each first interface to operatively connect to a respective one of the plural terminating devices via a dedicated signaling link external to the intermediate device;

a second interface to operatively connect to the upstream device via a dedicated signaling link external to the intermediate device;

circuitry to provide communications from the plural terminating devices to the upstream device via the second interface; and

physical layer circuitry to perform presence detection for the set of first interfaces, the intermediate device to provide presence detection information from the physical layer circuitry for the plural terminating devices to the upstream device.

2. The intermediate device of claim 1, embodied as a hub.

3. The intermediate device of claim 2, where the hub uses a communication protocol that is compliant with at least one of PCI EXPRESS or the SATA protocol.

4. The intermediate device of claim 1, wherein the intermediate device is PCI EXPRESS compliant, and where the physical layer circuitry to perform presence detection comprises a detector to monitor a physical layer signal for each one of the first interfaces.

5. The intermediate device of claim 4, further comprising an encoder, coupled to the detector, to generate a symbol representing the physical layer signal, the intermediate device to transmit the symbol to the upstream device via the second interface.

6. The intermediate device of claim 5, where the symbol is a digital control character.

7. The intermediate device of claim 1, where the physical layer circuitry to perform presence detection is to perform presence detection based on line characteristics of the dedicated signaling link for a respective first interface.

8. The intermediate device of claim 7, where the physical layer circuitry to perform presence detection is to perform presence detection based on RC characteristics associated with the dedicated signaling links for each respective first interface.

9. The intermediate device of claim 1, where at least one of the signaling links comprises a differential signaling path.

10. The intermediate device of claim 1, where at least one interface of the set of first interfaces or the second interface comprises at least a four-wire signaling interface to connect to at least a differential transmit signal path and a differential receive signal path.

11. The intermediate device of claim 1, where each first interface and the second interface each comprises at least a four-wire signaling interface to connect to at least two wires for each one of a differential transmit signal pair and a differential receive signal pair, the second interface to transmit a state for each first interface to the upstream device in a time-multiplexed manner.

12. The intermediate device of claim 11, where the second interface is to transmit the state for each first interface to the upstream device in respective time slices dedicated to respective terminating devices.

13. The intermediate device of claim 12, where the state for each first interface is to be transmitted to the upstream device using a control character and a terminating device identifier.

14. The intermediate device of claim 1, further comprising a circuit to detect loss of signal for a terminating device operatively connected to one of the first interfaces, where the intermediate device is further to responsively transmit a loss of signal indication to the upstream device.

15. The intermediate device of claim 1, further comprising circuitry to detect loss of signal for each terminating device operatively connected to one of the first interfaces, where the intermediate device is further to relay a loss of signal state to the upstream device with an indication of a corresponding one of the plural terminating devices.

16. The intermediate device of claim 1, where the intermediate device is to receive a serial bit stream from the upstream device, to demultiplex the serial bit stream into packets, and to route the demultiplexed packets to appropriate terminating devices.

51. The device of claim 1, wherein the circuitry to provide communications from the plural terminating devices to the upstream device via the second interface comprises circuitry to time-multiplex communications from the plural terminating devices to the upstream device via the second interface.

17. An intermediate device for use in a signaling system having an upstream device and one or more downstream devices that each respond to the upstream device, the intermediate device comprising:

one or more first interfaces, each first interface to operatively connect to a downstream device via a dedicated signaling link;

a second interface to operatively connect to the upstream device via a dedicated signaling link;

circuitry to transmit communications from the one or more downstream devices to the upstream device;

circuitry to prevent false presence detection by the upstream device of at least one downstream device.

18. The intermediate device of claim 17, where:

the one or more first interfaces comprise plural first interfaces, each to operatively connect to a respective downstream device via a dedicated signaling link; and

the circuitry to transmit communications comprises circuitry to time-multiplex communications from the downstream devices to the upstream device.

19. The intermediate device of claim 17, embodied as a hub.

20. The intermediate device of claim 19, where the hub uses a communication protocol that is compliant with at least one of PCI EXPRESS or the SATA protocol.

21. The intermediate device of claim 17, wherein the intermediate device is PCI EXPRESS compliant, and where the circuitry to prevent false presence detection comprises a detector to monitor physical layer signals for each one of the one or more first interfaces.

22. The intermediate device of claim 21, further comprising an encoder, coupled to the detector, to generate a symbol representing a physical layer signal, the intermediate device to transmit the symbol to the upstream device via the second interface.

23. The intermediate device of claim 22, where the symbol is a digital control character.

24. The intermediate device of claim 17, where the circuitry to prevent false presence detection is to perform presence detection based on line characteristics of the dedicated signaling link for a respective first interface.

25. The intermediate device of claim 24, where the circuitry to prevent false presence detection is to perform presence detection based on RC characteristics associated with the dedicated signaling links for each respective first interface.

26. The intermediate device of claim 17, where the intermediate device further comprises one or more switches to switchably couple a termination network to the second interface to reflect presence of a downstream device to the upstream device via the second interface.

27. The intermediate device of claim 17, where at least one of the signaling links comprises a differential signaling path.

28. The intermediate device of claim 17, where at least one of the one or more first interfaces or the second interface comprises at least a four-wire signaling interface to connect to at least a differential transmit signal path and a differential receive signal path.

29. The intermediate device of claim 28, where:

the one or more first interfaces comprise plural first interfaces, each to operatively connect to a respective downstream device via a dedicated signaling link; and

each first interface and the second interface each comprises at least a four-wire signaling interface to connect to at least two wires for each one of a differential transmit signal pair and a differential receive signal pair, the second interface to transmit a state for each first interface to the upstream device in a time-multiplexed manner.

30. The intermediate device of claim 29, where the second interface is to transmit the state for each first interface to the upstream device in respective time slices dedicated to each downstream device.

31. The intermediate device of claim 30, where the state for each first interface is to be transmitted to the upstream device using a control character and a downstream device identifier.

32. The intermediate device of claim 17, further comprising a circuit to detect loss of signal for a downstream device operatively connected to one of the one or more first interfaces, where the intermediate device is further to responsively transmit a loss of signal indication to the upstream device.

33. The intermediate device of claim 17, further comprising circuitry to detect loss of signal for each downstream device operatively connected to one of the one or more first interfaces, where the intermediate device is further to relay a loss of signal state to the upstream device with an indication of a corresponding downstream device.

34. The intermediate device of claim 17, where:

the one or more first interfaces comprise plural first interfaces, each to operatively connect to a respective downstream device via a dedicated signaling link; and

the intermediate device is to receive a serial bit stream from the upstream device, to demultiplex the serial bit stream into packets, and to route the demultiplexed packets to appropriate downstream devices.

35. An intermediate device to couple an upstream device with one or more downstream devices, the intermediate device comprising:

one or more first interfaces, each first interface comprising at least a four-wire connection to operatively connect to a respective downstream device via a dedicated signaling link, the four-wire connection to connect to a differential transmit signal pair and a differential receive signal pair;

a second interface to operatively connect to the upstream device via a differential signaling link;

circuitry to relay communications from the one or more downstream devices to the upstream device; and

physical layer circuitry to perform presence detection for each first interface, the intermediate device to relay presence detection information from the physical layer circuitry to the upstream device.

36. The intermediate device of claim 35, where:

the one or more first interfaces comprise plural first interfaces, each to operatively connect to a respective downstream device via a dedicated signaling link; and

the circuitry to relay communications comprises a multiplexer to time-multiplex the communications from the downstream devices to the upstream device.

37. The intermediate device of claim 35, embodied as a hub.

38. The intermediate device of claim 37, where the hub uses a communication protocol that is compliant with at least one of PCI EXPRESS or the SATA protocol.

39. The intermediate device of claim 35, wherein the intermediate device is PCI EXPRESS compliant, and where the physical layer circuitry to perform presence detection comprises a detector to a monitor physical layer signal present for each one of the one or more first interfaces.

40. The intermediate device of claim 39, further comprising an encoder, coupled to the detector, to generate a symbol representing a physical layer signal, the intermediate device to transmit the symbol to the upstream device via the second interface.

41. The intermediate device of claim 40, where the symbol is a digital control character.

42. The intermediate device of claim 35, where the physical layer circuitry to perform presence detection is to perform presence detection based on line characteristics of the dedicated signaling link for the respective first interface.

43. The intermediate device of claim 42, where the physical layer circuitry to perform presence detection is to perform presence detection based on RC characteristics associated with the dedicated signaling links for each respective first interface.

44. The intermediate device of claim 35, where the intermediate device further comprises one or more switches to switchably couple a termination network to the second interface to reflect presence of a downstream device to the upstream device via the second interface.

45. The intermediate device of claim 35, where the second interface comprises at least a four-wire signaling interface to connect to at least a differential transmit signal path and a differential receive signal path.

46. The intermediate device of claim 35, where:

the one or more first interfaces comprise plural first interfaces, each to operatively connect to a respective downstream device via a dedicated signaling link; and

the second interface is to transmit a state for each first interface to the upstream device in time slices dedicated to respective downstream devices.

47. The intermediate device of claim 46, where the state for each first interface is transmitted to the upstream device using a control character and a downstream device identifier.

48. The intermediate device of claim 35, further comprising a circuit to detect loss of signal for a downstream device operatively connected to one of the first interfaces, where the intermediate device is further to responsively transmit a loss of signal indication to the upstream device.

49. The intermediate device of claim 35, further comprising circuitry to detect loss of signal for each downstream device operatively connected to one of the first interfaces, where the intermediate device is further to relay a loss of signal state to the upstream device with an indication of a corresponding downstream device.

50. The intermediate device of claim 35, where:

the one or more first interfaces comprise plural first interfaces, each to operatively connect to a respective downstream device via a dedicated signaling link; and

the intermediate device is to receive a serial bit stream from the upstream device, to demultiplex the serial bit stream into packets, and to route the demultiplexed packets to appropriate downstream devices via the appropriate differential transmit signal pair.