Interface for bridging out-of-band information and preventing false presence detection of terminating devices

• US 20060129733A1
• Filed: 12/15/2004
• Published: 06/15/2006
• Est. Priority Date: 12/15/2004
• Status: Active Grant

• Current Assignee: Rambus Inc.
• Original Assignee: Rambus Inc.
• Inventors: Sobelman, Michael J.
• Granted Patent: US 7,461,192 B2
• Time in Patent Office: Days
• 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. A circuit, comprising:

a first interface having an input to receive a signal from a first communication link, wherein the signal includes out-of-band (OOB) information;

a detector coupled to the first interface to detect the OOB information;

an encoder coupled to the detector to encode the OOB information into corresponding symbols; and

a second interface coupled to the encoder and having an output to transmit the symbols to the second communication link.

2. The circuit of claim 1, wherein the second interface is coupled a serial data link.

3. The circuit of claim 1, wherein the encoder is an 8B/10B encoder and the symbols are control characters.

4. The circuit of claim 1, wherein the OOB information represents a “

Loss of Signal”

status on the first communication link.

5. The circuit of claim 1, wherein the OOB information includes signal state information selected from the set comprising Electrical Idle, Receiver Detect, Beacon, COMReset/COMInit and COMWake.

6. The circuit of claim 1, further comprising a serializer coupled to the encoder to serialize the symbols;

wherein the second interface includes a transmitter coupled to the serializer to transmit the serialized symbols on the second communication link.

7. The circuit of claim 1, wherein the encoder encodes at least a portion of the signal received by the first interface into a stream of data symbols corresponding to an in-band data signal.

8. A circuit, comprising:

a first interface having an input that receives a signal including one or more symbols representing encoded out-of-band (OOB) information from a first communication link;

a decoder coupled to the first interface that decodes the one or more symbols into reconstructed OOB information; and

a second interface coupled to the decoder and having an output for transmitting the reconstructed OOB information to a second communication link.

9. The circuit of claim 8, wherein the first interface is coupled to a serial data link.

10. The circuit of claim 8, wherein the decoder is an 8B/10B decoder and the one or more symbols are control characters.

11. The circuit of claim 8, wherein the encoded OOB information represents a “

Loss of Signal”

status on the first communication link.

12. The circuit of claim 8, wherein the encoded OOB information includes signal state information selected from the set comprising Electrical Idle, Receiver Detect, Beacon, COMReset/COMInit and COMWake.

13. The circuit of claim 8, wherein the received signal includes one or more data symbols corresponding to an in-band data signal, and the decoder decodes the data symbols to generate the data signal.

14. The circuit of claim 13, including a deserializer coupled to the decoder for deserializing the data symbols prior to decoding;

wherein the second interface includes a transmitter coupled to the decoder for transmitting the data signal on the second communication link.

15. A method of bridging out-of-band (OOB) information across a device, comprising:

receiving a signal from a first communication link;

determining if the signal includes OOB information; and

if the signal includes OOB information;

identifying the OOB information;

selecting a symbol representing the OOB information; and

transmitting the symbol on a second communication link.

16. The method of claim 15, wherein the OOB information comprises “

Loss of Signal”

.

17. The method of claim 15, wherein the OOB information includes signal state information selected from the set comprising Electrical Idle, Receiver Detect, Beacon, COMReset/COMInit and COMWake.

18. The method of claim 15, further comprising:

encoding an in-band data signal;

serializing the encoded data signal; and

transmitting the serialized encoded data signal on the second communication link.

19. A method of bridging out-of-band (OOB) information across a device, comprising:

receiving a signal comprising a plurality of symbols from a first communication link;

evaluating at least some of the symbols in the plurality of symbols to determine if any of the evaluated symbols is associated with OOB information; and

for any evaluated symbols that are associated with OOB information,

identifying a corresponding symbol;

selecting OOB information associated with the symbol; and

transmitting the OOB information on a second communication link.

20. The method of claim 19, wherein the OOB information comprises “

Loss of Signal”

.

21. The method of claim 19, wherein the OOB information includes signal state information selected from the set including Electrical Idle, Receiver Detect, Beacon, COMReset/COMInit and COMWake.

22. The method of claim 19, wherein the signal includes data symbols corresponding to an in-band data signal, the method further comprising:

deserializing the data symbols;

decoding the data symbols; and

transmitting a decoded data signal on the second communication link.

23. A circuit for preventing a first device on a first communication link from falsely detecting presence of another device on a second communication link, comprising:

a receiver, coupled to the first communication link, that receives a signal from the first device coupled to the first communication link;

a termination network;

at least one switch for switchably coupling the termination network to an input of the receiver; and

an actuator, coupled to the switches, that control the state of the at least one switch in response to a connection status signal indicating whether a second device is coupled to the second communication link.

24. The circuit of claim 23, wherein the termination network is a resistive network that, when connected to the receiver inputs, causes the receiver to appear transparent to the first device coupled to the first communication link.

25. The circuit of claim 23, wherein the connection status signal is encoded and transmitted to another device.

26. A system for bridging out-of-band (OOB) information across an interface, comprising:

means for receiving a signal from a first communication link;

means for determining if the signal is OOB information, and;

if the signal is OOB information;

means for identifying the OOB information;

means for selecting a symbol representing the OOB information; and

means for transmitting the symbol on a second communication link.

27. A computer readable medium containing data representing a circuit that includes:

a first interface having an input to receive a signal from a communication link, wherein the signal includes out-of-band (OOB) information;

a detector coupled to the first interface to detect the OOB information;

an encoder coupled to the detector to encode the OOB information into corresponding symbols; and

a second interface coupled to the encoder and having an output to transmit the symbols to the second communication link.

28. A computer readable medium containing data representing a circuit that includes:

a first interface having an input that receives a signal including one or more symbols representing encoded out-of-band (OOB) information from a first communication link;

a decoder coupled to the first interface that decodes the one or more symbols into reconstructed OOB information; and

a second interface coupled to the decoder and having an output for transmitting the reconstructed OOB information to a second communication link.