Method and apparatus for border node behavior on a full-duplex bus

• US 20070294449A1
• Filed: 08/27/2007
• Published: 12/20/2007
• Est. Priority Date: 01/18/2000
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Whitby-Strevens, Colin, Hauck, Jerrold
• Granted Patent: US 7,822,898 B2
• Time in Patent Office: Days
• US Class Current: 710/240
• CPC Class Codes: H04L 12/40052 High-speed IEEE 1394 serial bus bus transfer protocol on a daisy chain bus using an embedded synchronisation G06F13/426
• CPC Class Codes: H04L 12/40058 Isochronous transmission
• CPC Class Codes: H04L 12/40071 Packet processing; Packet format adaptation of digital video signals for transport over a specific network H04N21/2381, H04N21/4363, H04N21/4381; packet switches H04L49/00; intermediate storage or scheduling H04L49/90
• CPC Class Codes: H04L 12/6418 Hybrid transport

Abstract

A method and apparatus relating to the behavior of border nodes within a high performance serial bus system is disclosed. A method for determining and communicating the existence of a hybrid bus is disclosed. A method for determining a path to a senior border node is disclosed, as is a method for identifying a senior border node Various methods for properly issuing gap tokens within a beta cloud are disclosed.

Claims

1-3. -3. (canceled)

4. A method of preventing a serial bus device from granting requests during one or more intervals of time, the method comprising:

allowing the serial bus device to grant requests only when it is determined that (i) the serial bus device presently has the exclusive right to grant requests among a first set of serial bus devices, and (ii) that requests are presently allowed to be transmitted over the serial bus.

5. A method of preventing a serial bus device from granting requests during one or more intervals of time, the method comprising:

determining whether the serial bus device has the right to grant requests among a first set of serial bus devices;

detecting the type of the serial bus;

selecting a protocol based at least in part upon the detected type of the serial bus; and

determining whether requests are presently allowed to be transmitted over the serial bus, wherein said determination is based at least in part upon said protocol.

6. The method of claim 5, wherein said selecting a protocol further comprises selecting a first protocol if every device on the serial bus is compliant with a certain specification.

7. The method of claim 6, wherein the specification comprises the IEEE 1394b specification.

8. The method of claim 6, wherein the first protocol allows the serial bus device to grant requests after receiving a signal indicating the end of an isochronous packet.

9. The method of claim 6, wherein if the serial bus device receives a signal indicating the end of an asynchronous packet and the end of a subaction has not been detected, the first protocol prohibits the serial bus device from granting requests during a first interval of time, the first interval of time commencing after the serial bus device receives the signal indicating the end of the asynchronous packet.

10. The method of claim 6, wherein if the serial bus device receives a signal indicating the end of an asynchronous packet, and an acknowledgement has not been detected over the serial bus, the first protocol prevents the serial bus device from granting requests during a first interval of time, the first interval of time commencing after the serial bus device receives the signal indicating the end of the asynchronous packet.

11. The method of claim 6, wherein if the serial bus device receives a signal indicating the end of an asynchronous packet and detects the end of a subaction, the first protocol allows the serial bus device to grant requests.

12. The method of claim 5, wherein said selecting a protocol further comprises selecting a second protocol if not every device on the serial bus is compliant with a certain specification.

13. The method of claim 12, wherein said specification comprises the IEEE 1394b specification.

14. The method of claim 12, wherein if the serial bus device receives a signal indicating the end of an isochronous packet, the second protocol prevents the serial bus device from granting requests during a first interval of time and a second interval of time.

15. The method of claim 14, wherein at least one of the first interval of time and the second interval of time is based at least in part on an idle period of bus activity and a period of hysteresis.

16. The method of claim 15, wherein the idle period of bus activity comprises a subaction gap.

17. The method of claim 15, wherein the idle period of bus activity comprises an arbitration reset gap.

18. The method of claim 15, wherein the period of hysteresis comprises an arbitration delay period.

19. The method of claim 14, wherein the second protocol allows the serial bus device to grant requests during a third interval of time, wherein the third interval of time occurs after the serial bus device receives a signal indicating the end of an isochronous packet, but before the first interval of time.

20. The method of claim 14, wherein the second protocol allows the serial bus device to grant requests during a fourth interval of time, the fourth interval of time occurring after the first interval of time but before the second interval of time.

21. The method of claim 12, wherein if the serial bus device receives a signal indicating the end of an asynchronous packet and the end of a subaction has not been detected, the serial bus device does not grant requests during a first interval of time and a second interval of time.

22. The method of claim 21, wherein at least one of the first interval of time and the second interval of time is based at least in part on an idle period of bus activity and a period of hysteresis.

23. The method of claim 22, wherein the idle period of bus activity comprises a subaction gap.

24. The method of claim 22, wherein the idle period of bus activity comprises an arbitration reset gap.

25. The method of claim 22, wherein the period of hysteresis comprises an arbitration delay period.

26. The method of claim 21, wherein the serial bus device grants requests during a third interval of time, the third interval of time occurring after the first interval of time but before the second interval of time.

27. The method of claim 12, wherein if the serial bus device receives a signal indicating the end of an asynchronous packet but no acknowledgement, the serial bus device does nor grant requests during a first interval of time and a second interval of time.

28. The method of claim 27, wherein the second protocol allows the serial bus device to grant requests during a third interval of time, wherein the third interval of time occurs after the first interval of time but before the second interval of time.

29. The method of claim 12, wherein if the serial bus device receives a signal indicating the end of an asynchronous packet and detects the end of a subaction, the serial bus device does not grant requests during a first interval of time.

30. The method of claim 29, wherein the first interval of time is based at least in part on an idle period of bus activity and a period of hysteresis.

31. The method of claim 30, wherein the idle period of bus activity comprises an arbitration reset gap.

32. The method of claim 30, wherein the period of hysteresis comprises an arbitration delay period.

33. The method of claim 29, wherein the second protocol allows the serial bus device to grant requests after receiving the signal indicating the end of the asynchronous packet, but before the first interval of time.

34. The method of claim 5, wherein said determining whether the serial bus device has the right to grant requests comprises determining whether the serial bus device has received a first symbol.

35. The method of claim 5, wherein said determining whether the serial bus device has the right to grant requests comprises determining whether the serial bus device has received a second symbol over a junior port.

36. The method of claim 35, wherein the second symbol comprises a data end symbol.

37. The method of claim 5, wherein said determining whether the serial bus device has the right to grant requests comprises determining whether the serial bus device has transmitted a packet into a designated group of serial bus devices.

38. A method for controlling when a serial bus device on a hybrid bus is able to grant requests, the method comprising:

preventing the serial bus device from granting requests during a first interval of time, said first interval of time comprising a first idle period of bus activity and a first period of hysteresis.

39. The method of claim 38, wherein the first idle period of bus activity comprises an arbitration reset gap.

40. The method of claim 38, wherein the first period of hysteresis comprises an arbitration delay period.

41. The method of claim 38, wherein the first interval of time commences after a second interval of time and a third interval of time, the second interval of time comprising a second idle period of bus activity and a second period of hysteresis, the third interval of time occurring after said second interval of time but before said first interval of time.

42. The method of claim 41, further comprising:

allowing the serial bus device to grant requests during the third interval of time.

43. The method of claim 41, further comprising:

allowing the serial bus device to grant requests during the second interval of time only when the end of an asynchronous packet has been detected and the end of a subaction has been detected.

44. A method for controlling request granting in a serial bus device on a beta bus, the method comprising:

allowing the serial bus device to grant requests immediately upon;

(i) detecting the end of an isochronous packet, or (ii) upon detecting the end of an asynchronous packet provided that the end of a subaction has also been detected; and

allowing the serial bus device to grant requests after a period of delay upon detecting the end of an asynchronous packet, and where the end of a subaction has not been detected.

45. An apparatus adapted to prevent a serial bus device from granting requests during one or more intervals of time, the apparatus comprising:

a first module adapted to determine whether the serial bus device can grant requests among a first set of serial bus devices;

a second module adapted to detect the type of the serial bus;

a third module adapted to select a protocol based at least in part upon the detected type of the serial bus; and

a fourth module adapted to determine whether requests are presently allowed to be transmitted over the serial bus, said determination based at least in part upon said protocol.