Method and apparatus for arbitration on a data bus

• US 8,473,660 B2
• Filed: 03/19/2012
• Issued: 06/25/2013
• Est. Priority Date: 11/05/1999
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Johas Teener, Michael D.
• Primary Examiner(s): Myers, Paul R
• Application Number:
  US13/424,280
• Publication Number:
  US 20120179850A1
• Time in Patent Office: 463 Days
• Field of Search: 710107-119, 710240-244
• US Class Current: 710/240
• CPC Class Codes: G06F 13/3625 using a time dependent access
• CPC Class Codes: G06F 13/4295 using an embedded synchronisation

Abstract

A method and apparatus for arbitrating on a high performance serial bus is disclosed. The invention provides for a plurality of arbitration phases and an arbitration advancing means.

Claims

1. A method for requesting bus arbitration in a network comprising a bus, a master node, and one or more non-master nodes, a bus cycle comprising an isochronous phase and an asynchronous phase, said method comprising:

determining whether a non-master node of the one or more non-master nodes wants to arbitrate in the isochronous phase;

when the non-master node wants to arbitrate in the isochronous phase, issuing an isochronous request to arbitrate, the isochronous phase comprising a period of time where isochronous requests are serviced before asynchronous requests; and

when the non-master node does not want to arbitrate in the isochronous phase, issue an isochronous non-arbitration request.

2. The method of claim 1, wherein the isochronous request to arbitrate is for a next state within the isochronous phase.

3. The method of claim 2, where the isochronous request to arbitrate comprises an isochronous even request, and wherein the next state is an even state and a current state is an odd state.

4. The method of claim 1, wherein issuing the isochronous request to arbitrate comprises sending the isochronous request to arbitrate to the master node.

5. The method of claim 4, wherein the master node comprises a Bus Owner/Supervisor/Selector (BOSS) node.

6. The method of claim 5, wherein the BOSS node advances a phase between the isochronous phase and the asynchronous phase.

7. The method of claim 5, wherein the BOSS node advances a state within the isochronous phase from an odd state to an even state.

8. A non-master node apparatus on a network, the non-master node apparatus comprising:

at least one network interface, the at least one network interface configured for operation within a bus cycle comprising;

an asynchronous phase; and

an isochronous phase, the isochronous phase comprising a period of time where isochronous requests are serviced before asynchronous requests and a plurality of states;

a processor; and

a non-transitory computer readable apparatus comprising a storage medium storing at least one computer program, the at least one computer program comprising a plurality of instructions which, when executed by the processor, cause the processor to;

determine whether the non-master node apparatus wants to arbitrate in a next isochronous phase;

when the non-master node apparatus wants to arbitrate in the next isochronous phase, issue an isochronous request to arbitrate in a next state of the plurality of states in the isochronous phase; and

when the non-master node apparatus does not want to arbitrate in the next isochronous phase, issue an isochronous non-arbitration request.

9. The non-master node apparatus of claim 8, wherein the at least one network interface is configured to communicate with a master node, the master node advances from the isochronous phase to the asynchronous phase.

10. The non-master node apparatus of claim 9, wherein the master node comprises a Bus Owner/Supervisor/Selector (BOSS) node.

11. The non-master node apparatus of claim 9, wherein the computer program comprises further instructions, when executed on the processor, when the non-master node apparatus wants to arbitrate in the isochronous phase, send the isochronous request to arbitrate in the next state to the BOSS node.

12. The non-master node apparatus of claim 9, wherein the master node services all isochronous requests before the master node services any asynchronous requests.

13. A non-master node apparatus on a network, the non-master node apparatus comprising:

a first logic configured to communicate on the network, the network having a bus cycle comprising an isochronous state, the isochronous state comprising an even phase and an odd phase;

a second logic configured to determine whether the non-master node apparatus wants to arbitrate;

a third logic configured to, when the non-master node apparatus wants to arbitrate, issue an isochronous request to arbitrate in a next state of the isochronous phase; and

a fourth logic configured to, when the non-master node apparatus does not want to arbitrate, issue an isochronous non-arbitration request.

14. The non-master node apparatus of claim 13, wherein the first logic is further configured to communicate with a master node.

15. The non-master node apparatus of claim 14, wherein the master node comprises a Bus Owner/Supervisor/Selector (BOSS) node.

16. The non-master node apparatus of claim 15, wherein the third logic is further configured to send the isochronous request to arbitrate to the BOSS node.

17. The non-master node apparatus of claim 15, wherein the fourth logic is further configured to send the isochronous non-arbitration request to the BOSS node.

18. The non-master node apparatus of claim 13, wherein the bus cycle of the network further comprises an asynchronous state, the asynchronous state occurring after the isochronous state.

19. The non-master node apparatus of claim 18, wherein a master node advances a state from the isochronous state to the asynchronous state.

20. The non-master node apparatus of claim 18, wherein the isochronous request to arbitrate is prioritized over asynchronous requests to arbitrate.