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

• US 9,792,241 B2
• Filed: 04/20/2015
• Issued: 10/17/2017
• Est. Priority Date: 12/15/2004
• Status: Active Grant

• Current Assignee: Rambus Inc.
• Original Assignee: Rambus Inc.
• Inventors: Sobelman, Michael J.
• Primary Examiner(s): AUVE, GLENN ALLEN
• Application Number:
  US14/691,487
• Publication Number:
  US 20150370743A1
• Time in Patent Office: 911 Days
• 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 downstream devices, the intermediate device comprising:

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

physical layer circuitry coupled to the set of first interfaces to perform presence detection for the plural downstream devices;

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 downstream devices to the upstream device via the second interface; and

the second interface configured to provide presence detection information from the physical layer circuitry for the plural downstream devices to the upstream device.

2. The intermediate device of claim 1, embodied as a repeater, multiplexer/demultiplexer, router, bridge, or hub.

3. The intermediate device of claim 1, wherein the physical layer circuitry to perform presence detection comprises a detector to monitor a physical layer signal for each one of the first interfaces.

4. The intermediate device of claim 3, 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.

5. 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.

6. The intermediate device of claim 5, 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.

7. The intermediate device of claim 1, where the second interface is to transmit a state for each first interface to the upstream device in a time-multiplexed manner.

8. The intermediate device of claim 7, where the state for each first interface is to be transmitted to the upstream device in respective time slices dedicated to respective downstream devices.

9. The intermediate device of claim 7, where the state for each first interface is to be transmitted to the upstream device using a control character and a downstream device identifier.

10. The intermediate device of claim 1, 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.

11. The intermediate device of claim 10, where the intermediate device is further to transmit the loss of signal indication to the upstream device with an indication of the downstream device corresponding to the loss of signal detection.

12. 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 downstream devices.

13. 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; and

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

14. The intermediate device of claim 13, 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.

15. The intermediate device of claim 13, where the intermediate device further comprises a detector to monitor the communications from the one or more downstream devices to determine if a downstream device is transmitting out-of-band (OOB) information or in-band data.

16. The intermediate device of claim 15, where, in response to a determination that a downstream device is transmitting OOB information, the detector is further to send a first signal to an encoder indicating that the monitored communications from the downstream device are OOB information, where the encoder is to cease standard encoding and transmit a predefined symbol identifying the OOB information.

17. The intermediate device of claim 15, where, in response to a determination that a downstream device is transmitting in-band data, the detector is further to send a second signal to an encoder indicating that the monitored communications from the downstream device are in-band data, where the encoder is to start or restart a standard encoding process for the in-band data.

18. The intermediate device of claim 13, where the intermediate device further comprises downstream transmitter circuitry to transmit communications from the upstream device to the one or more downstream devices, and where the false presence detection prevention circuitry prevents false presence detection by monitoring the downstream transmitter circuitry.

19. The intermediate device of claim 18, where the false presence detection prevention circuitry performs presence detection based on RC characteristics associated with the downstream transmitter circuitry.

20. 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.