Diagnostics for Serial Communication Busses

• US 20100002587A1
• Filed: 07/01/2008
• Published: 01/07/2010
• 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
• Granted Patent: US 8,159,956 B2
• Time in Patent Office: Days
• 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 bus 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 bus, comprising:

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

a power interface configured to receive operating power for the respective module from an external power source;

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

memory configured to store the digital diagnostic data;

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

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.

2. The serial communications bus of claim 1, wherein the serial communication bus 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 bus of claim 1, wherein the serial cable includes one of:

an optical cable; and

an electrically-conductive cable.

4. The serial communications bus of claim 1, wherein the first interface is also configured to communicate with a 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 bus of claim 1, wherein the first interface is also configured to allow an external host to write the digital diagnostic data to the memory.

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

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

8. The serial communications bus of claim 1, wherein each of the first and second modules comprise a voltage controller configured to encode digital diagnostic data onto a serial data signal by adjusting voltage levels of the serial data signal sent to a host.

9. The serial communications bus of claim 1, wherein each of the first and second modules comprise a voltage amplitude sensor configured to decode digital diagnostic data encoded onto a serial data signal by determining voltage levels of the serial data signal sent from a host.

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

11. The serial communications bus of claim 10,

wherein the serial cable is an electrically-conductive cable;

and

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

12. The serial communications bus of claim 10,

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.

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

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

15. The serial communications bus of claim 14,

wherein the serial cable is an electrically-conductive cable;

and

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

16. The serial communications bus of claim 14,

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.

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

18. The serial communications bus 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.

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

20. A serial communications bus, comprising:

serial communications module, comprising;

a power interface configured to receive operating power for the module from an external power source;

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 from the memory; and

a second interface configured to serially communicate data to a second module via a serial cable coupled to the second interface circuit.

21. The serial communications bus of claim 20, wherein the serial communication bus supports one or more of:

a Serial Advanced Technology Attachment (SATA) standard; and

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

22. The serial communications bus of claim 20, wherein the serial cable includes one of:

an optical cable; and

an electrical cable.

23. The serial communications bus of claim 20, wherein the first interface is also configured to communicate with a host using one or more of:

a Serial Advanced Technology Attachment (SATA) protocol; and

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

24. The serial communications bus of claim 20, wherein the first interface is also configured to allow an external host to write the digital diagnostic data to the memory.

25. The serial communications bus of claim 20, wherein the digital diagnostic data is stored in memory-mapped locations in the memory.

26. 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; and

transmitting the serial data signal to the requester.

27. The method of claim 26, wherein prior to receiving a request for the digital diagnostic data, the method further comprises:

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.

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

the powered module; and

an external device.

29. The method of claim 26, 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 to the host.

30. The method of claim 26, 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 voltage levels for the serialized digital diagnostic data based on a voltage encoding map; and

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

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

32. The method of claim 26, 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.

33. The method of claim 26 wherein the requester includes one or more of:

a host system; and

another powered module.

34. 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; and

storing the digital diagnostic data in memory.

35. The method of claim 34, wherein obtaining the digital diagnostic data from the serial data signal includes:

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

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

deserializing the serialized digital diagnostic data to obtain the digital diagnostic data.

36. The method of claim 35, wherein the digital diagnostic data can be encoded into one or more voltage levels in the digital diagnostic signal.

37. The method of claim 34, 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.

38. The method of claim 34, wherein the sender includes one of:

a powered module; and

a host system.

39. The method of claim 34, wherein the memory is one of:

a memory for the powered module; and

a memory for a host system.