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

• US 6,639,918 B1
• Filed: 01/18/2000
• Issued: 10/28/2003
• Est. Priority Date: 01/18/2000
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Whitby-Strevens, Colin, Hauck, Jerrold V.
• Primary Examiner(s): Cangialosi, Salvatore
• Application Number:
  US09/484,479
• Time in Patent Office: 1,379 Days
• Field of Search: 370/257, 370/252, 370/253, 370/389, 370/462, 370/461, 709/200, 709/232, 709/233, 709/328, 710/240-244
• US Class Current: 370/462
• 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 12/6418 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.

A method for returning control to the senior border node is disclosed. A method for determining whether a BOSS node may issue a grant is disclosed.

Claims

1. In a serial bus communications system, a method for determining whether a BOSS node may issue a grant for a pipelined Beta request comprising:

providing a first and second indicator; and

issuing a grant for a pipelined Beta request by the BOSS only when both said first and second indicators are set.

2. The method of claim 1 wherein said first indicator is set when the BOSS receives a GRANT packet.

3. The method of claim 1 wherein said first indicator is set when said BOSS is the first node to transmit into a beta cloud.

4. The method of claim 1, further comprising setting said second indicator after the end of an isochronous packet if said system comprises a B bus.

5. The method of claim 1, wherein said system is a hybrid bus and there has been an end of an isochronous packet;

said method further comprises the acts of;

setting said second indicator after the end of an isochronous packet. resetting said second indicator during a first quiet time;

setting said second indicator momentarily after said first quiet time;

resetting said second indicator during a second quiet time; and

setting said second indicator after said second quiet time.

6. The method of claim 1, wherein said system is a hybrid bus and there has not been an end of subaction, said method further comprising the acts of:

resetting said second indicator after the end of an asychronous packet;

resetting said second indicator during a first quiet;

setting said second indicator momentarily after said first quiet time;

resetting said second indicator during a second quiet time; and

setting said second indicator after said second quiet time.

7. The method of claim 1, wherein said system comprises a beta-only system and there has been an end of an asynchronous packet;

said method further comprising the acts of;

setting said second indicator after the end of an asynchronous packet.

8. The method of claim 1, wherein said system comprises a beta-only system and there has not been an end of subaction;

said method further comprising the acts of;

resetting said second indicator after the end of an asynchronous packet for a predetermined amount of time; and

setting said indicator thereafter.

9. The method of claim 2 wherein said predetermined amount of time is sufficient for said BOSS node to determine that an acknowledge packet is missing.

10. The method of claim 1, wherein said system is a hybrid bus and there has been an end of subaction, said method further comprising the acts of:

setting said second indicator after the end of an asynchronous packet;

resetting said second indicator during a second quiet time; and

setting said second indicator after said second quiet time.

11. The method of claim 1 wherein said first indicator is reset when said BOSS receives a packet from a P1394b-compliant port.

12. The method of claim 1 wherein said first indicator is reset when said BOSS issues either an explicit or implicit grant.

13. In a serial bus communications system, a method for determining whether a BOSS node may issue a grant for a Legacy request comprising:

providing a first indicator; and

issuing a grant for the Legacy request by the BOSS only if said first indicator is set.

14. The method of claim 13, wherein said indicator comprises a BOSS indicator.