Diagnostics for serial communication busses

• US 8,159,956 B2
• Filed: 07/01/2008
• Issued: 04/17/2012
• Est. Priority Date: 07/01/2008
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Ray Noble, Gayle Loretta, Gentieu, Paul
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): MEW, KEVIN D
• Application Number:
  US12/166,238
• Publication Number:
  US 20100002587A1
• Time in Patent Office: 1,386 Days
• Field of Search: 370241-242, 370/247, 370/251, 370/252, 375/228, 714/2, 714 21- 22, 714/25, 714/37, 714/47, 714/48
• US Class Current: 370/241
• CPC Class Codes: G06F 11/0745 in an input/output transactions management context input/output processing in general G06F13/00
• CPC Class Codes: G06F 11/0766 Error or fault reporting or storing
• CPC Class Codes: G06F 13/4295 using an embedded synchronisation
• CPC Class Codes: G06F 2213/0028 Serial attached SCSI [SAS]
• CPC Class Codes: G06F 2213/0032 Serial ATA [SATA]
• CPC Class Codes: H04B 10/801 using optical interconnects, e.g. light coupled isolators, circuit board interconnections

Abstract

The serial communication device includes a first module coupled to a second module via a serial cable. Each of the first and second modules comprise one or more of: a power interface, a controller, memory, a first interface, and a second interface. The power interface is configured to receive operating power for the respective module from an external power source. The controller is configured to obtain digital diagnostic data representative of operational characteristics of at least the respective module. The memory is configured to store the digital diagnostic data. The first interface is configured to allow an external host to read the digital diagnostic data from the memory. The second interface, which is distinct and separate from the first interface, is configured to serially communicate data to the second module via the serial cable.

Claims

1. A serial communications device, comprising:

a first module coupled to a second module via a serial cable, wherein each respective module of the first and second modules comprise;

a controller configured to obtain digital diagnostic data representative of operational characteristics of the respective module;

memory configured to store the digital diagnostic data;

a first interface configured to allow an external host to request the digital diagnostic data;

a second interface distinct and separate from the first interface, the second interface configured to serially communicate data between the first module and the second module via the serial cable; and

a signal controller configured to encode the digital diagnostic data onto a serial data signal for transmission via the first interface or the second interface by adjusting signal levels of the serial data signal while preserving original data in the serial data signal, wherein encoding the digital diagnostic data onto the serial data signal while preserving the original data in the serial data signal includes;

serializing the digital diagnostic data;

determining a series of signal levels for the serialized digital diagnostic data based on a signal encoding map; and

adjusting signal levels for the serial data signal based on the determined series of signal levels.

2. The serial communications device of claim 1, wherein the serial communications device supports one or more of:

a Serial Advanced Technology Attachment (SATA) standard; and

a Serial Attached Small Computer System Interface (SAS) standard.

3. The serial communications device of claim 1, wherein the serial cable includes one of:

an optical cable; and

an electrically-conductive cable.

4. The serial communications device of claim 1, wherein the first interface is also configured to communicate with the external host using one or more of:

a Serial Advanced Technology Attachment (SATA) protocol; and

a Serial Attached Small Computer System Interface (SAS) protocol.

5. The serial communications device of claim 1, wherein the first interface is also configured to allow an external host to write the digital diagnostic data to the memory of the respective module.

6. The serial communications device of claim 1, wherein an external host can read the digital diagnostic data from and/or write the digital diagnostic data to the memory of the respective module.

7. The serial communications device of claim 1, wherein the digital diagnostic data is stored in memory-mapped locations in the memory of the respective module.

8. The serial communications device of claim 1, wherein each of the respective modules comprises a signal amplitude sensor configured to decode digital diagnostic data encoded onto a serial data signal by determining signal levels of the serial data signal and obtaining the digital diagnostic data based on the signal encoding map.

9. The serial communications device of claim 1, wherein the second interface includes a transmitter configured to transmit serial data signals through the serial cable.

10. The serial communications device of claim 9,

wherein the serial cable is an electrically-conductive cable;

and

wherein the transmitter is configured to transmit electrical signals through the serial cable.

11. The serial communications device of claim 9,

wherein the serial cable is an optical cable;

wherein the transmitter is configured to;

convert electrical signals into corresponding optical signals; and

transmit optical signals through the serial cable;

wherein the transmitter is a laser transmitter.

12. The serial communications device of claim 11, wherein the second interface also includes a laser driver coupled to the laser transmitter, wherein the laser driver is configured to drive the laser transmitter.

13. The serial communications device of claim 1, wherein the second interface includes a receiver configured to receive serial data signals from the serial cable.

14. The serial communications device of claim 13,

wherein the serial cable is an electrically-conductive cable;

and

wherein the receiver is configured to receive electrical signals from the serial cable.

15. The serial communications device of claim 13,

wherein the serial cable is an optical cable;

wherein the receiver is configured to;

receive optical signals from the serial cable; and

convert the optical signals into corresponding electrical signals; and

wherein the receiver is a photodiode.

16. The serial communications device of claim 15, wherein the second interface also includes a post-amplifier coupled to the photodiode, wherein the post-amplifier is configured to generate a fixed output signal.

17. The serial communications device of claim 1, wherein the digital diagnostic data includes one or more of:

a transfer speed for the serial cable;

voltage amplitudes of signals received from the serial cable and or the host;

an optical power level of an optical signal received from the serial cable; and

a number of faults.

18. The serial communications device of claim 1, wherein each of the first and second modules is coupled to a host.

19. A serial communications device, comprising:

serial communications module, comprising;

a controller configured to obtain digital diagnostic data representative of operational characteristics of the module;

memory configured to store the digital diagnostic data;

a first interface configured to allow an external host to read the digital diagnostic data;

a second interface configured to serially communicate data to a second module via a serial cable coupled to the second interface; and

a signal controller configured to encode the digital diagnostic data onto a serial data signal for transmission via the first interface or the second interface by adjusting signal levels of the serial data signal while preserving original data in the serial data signal, wherein encoding the digital diagnostic data onto the serial data signal while preserving the original data in the serial data signal includes;

serializing the digital diagnostic data;

determining a series of signal levels for the serialized digital diagnostic data based on a signal encoding map; and

adjusting signal levels for the serial data signal based on the determined series of signal levels.

20. The serial communications device of claim 19, wherein the serial communications device supports one or more of:

a Serial Advanced Technology Attachment (SATA) standard; and

a Serial Attached Small Computer System Interface (SAS) standard.

21. The serial communications device of claim 19, wherein the serial cable includes one of:

an optical cable; and

an electrical cable.

22. The serial communications device of claim 19, wherein the first interface is also configured to communicate with the external host using one or more of:

a Serial Advanced Technology Attachment (SATA) protocol; and

a Serial Attached Small Computer System Interface (SAS) protocol.

23. The serial communications device of claim 19, wherein the first interface is also configured to allow an external host to write the digital diagnostic data to the memory of the serial communications module.

24. The serial communications device of claim 19, wherein the digital diagnostic data is stored in memory-mapped locations in the memory of the serial communications module.

25. A method, comprising:

at a powered module for a serial cable,

receiving a request for digital diagnostic data for the powered module from a requester;

locating the digital diagnostic data from the powered module;

encoding the digital diagnostic data onto a serial data signal while preserving the original data in the serial data signal, wherein encoding the digital diagnostic data onto the serial data signal while preserving the original data in the serial data signal includes;

serializing the digital diagnostic data;

determining a series of signal levels for the serialized digital diagnostic data based on a signal encoding map; and

adjusting signal levels for the serial data signal based on the determined series of signal levels

transmitting the serial data signal to the requester.

26. The method of claim 25, further comprising, prior to receiving the request for the digital diagnostic data:

monitoring at least the powered module to obtain digital diagnostic data; and

storing the obtained digital diagnostic data into a memory of the powered module.

27. The method of claim 26, wherein the monitoring is performed by one or more of:

the powered module; and

an external device.

28. The method of claim 25, further comprising:

receiving at the powered module the serial data signal from an additional host via the serial cable; and

transmitting the serial data signal with the adjusted signal levels to the host.

29. The method of claim 25, wherein the digital diagnostic data can be encoded into one or more signal levels in the serial data signal.

30. The method of claim 25, wherein the digital diagnostic data includes one or more of:

a transfer speed for the serial cable;

voltage amplitudes of signals received from the serial cable and or the host;

an optical power level of an optical signal received from the serial cable; and

a number of faults.

31. The method of claim 25 wherein the requester includes one or more of:

a host system; and

another powered module.

32. A method, comprising:

receiving a serial data signal which includes encoded digital diagnostic data from a sender;

obtaining the digital diagnostic data from the serial data signal, wherein obtaining the digital diagnostic data from the serial data signal includes;

determining a series of signal levels for the serial data signal;

obtaining serialized digital diagnostic data from the determined series of signal levels based on a voltage encoding map; and

deserializing the serialized digital diagnostic data to obtain the digital diagnostic data; and

storing the digital diagnostic data in memory.

33. The method of claim 32, wherein the digital diagnostic data can be encoded into one or more signal levels in the digital diagnostic signal.

34. The method of claim 32, wherein the digital diagnostic data includes one or more of:

a transfer speed for the serial cable;

voltage amplitudes of signals received from the serial cable and or the host;

an optical power level of an optical signal received from the serial cable; and

a number of faults.

35. The method of claim 32, wherein the sender includes one of:

a powered module; and

a host system.

36. The method of claim 32, wherein the memory is one of:

a memory for the powered module; and

a memory for a host system.