Split transaction protocol for a bus system

Patent metadata

Field	Value
Publication number	US-9892081-B2
Application number	US-201715600335-A
Country	US
Kind code	B2
Filing date	May 19, 2017
Priority date	Jul 27, 1999
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A method of and apparatus for communicating between a host and an agent. The method includes the step of performing a first transaction between a host controller and a hub. The hub is operable to perform a single transaction with an agent based on the first transaction. The method then includes the step of performing a second transaction between the host controller and the hub. The second transaction is based on the single transaction.

First claim

What is claim is:

1. A device, comprising:
a host controller to be coupled to a hub, wherein the host controller is to transmit data between the host controller and a first agent during a split transaction comprising:
executing a first transaction of the split transaction between the host controller and a hub;
executing a second transaction, wherein the host controller is to engage in the second transaction without waiting for a response from the first agent on the first transaction, wherein the host controller and the first agent transmit data at different speeds.

2. The device of claim 1 , wherein the host controller responds to a complete-split transaction to obtain the response from the first agent on the split transaction.

3. The device of claim 1 , wherein the controller is coupled with the first agent via the hub.

4. The device of claim 1 , wherein the first agent is one of a camera, compact disc player, speaker, microphone, video display device, scanner, joystick, mouse, or any combination thereof.

5. The device of claim 1 , wherein the second transaction is a complete split transaction.

6. The device of claim 1 , wherein the second transaction is a second transfer to a second agent.

7. The device of claim 1 , wherein a token phase is combined with a data phase of the first transaction.

8. The device of claim 1 , wherein the first transaction is an in transfer type.

9. The device of claim 1 , wherein the first transaction is an out transfer type.

10. A system comprising:
a host controller to be coupled to a hub and a first agent, said host controller to execute a first transaction to transfer data between the host controller and the first agent, wherein the host controller and the first agent transmit data at different speeds;
the host controller to engage a plurality of intermediate transactions without waiting for the transfer data between the host controller and the first agent to complete, and
the host controller to respond to a complete split transaction to obtain a result of the first transaction.

11. The system of claim 10 , wherein the intermediate transactions comprise a transfer request for the first agent, another agent on the same hub as the first agent, or another agent on another hub.

12. The system of claim 10 , wherein data is buffered to enable the intermediate transactions to be scheduled as periodic transactions, control transactions, or any combination thereof.

13. A method for implementing a split transaction including a host controller configured to execute the method, comprising:
issuing a start split transaction, wherein the start split transaction communicates a transfer request for an agent, wherein the host controller and an agent transmit data at different speeds;
obtaining a result from the agent in response to the transfer request; and
issuing a complete split transaction, wherein the complete split transaction communicates the result to a controller.

14. The method of claim 13 , wherein the result is at least one of a handshake or data.

15. The method of claim 13 , wherein the controller is to communicate with the agent via a hub.

16. The method of claim 13 , wherein the transfer request is a bulk in request.

17. The method of claim 13 , wherein the transfer request is a bulk out request.

18. The method of claim 13 , wherein the transfer request is an isochronous request.

19. The method of claim 13 , wherein the transfer request is an interrupt request.

Assignees

• Intel Corp

Inventors

• Garney John I
• Howard John S

Classifications

• G06F13/426

  using an embedded synchronisation, e.g. Firewire bus, Fibre Channel bus, SSA bus · CPC title

• G06F2213/40

  Bus coupling · CPC title

• G06F13/1673

  using buffers · CPC title

• G06F2213/4002

  Universal serial bus hub with a single upstream port · CPC title

• G06F3/14

  Digital output to display device {; Cooperation and interconnection of the display device with other functional units} · CPC title