Dual-role compatible USB hub device and method

• US 6,732,218 B2
• Filed: 07/26/2002
• Issued: 05/04/2004
• Est. Priority Date: 07/26/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Braun, Mark R., Carlson, Mark, Overtoom, Eric J.
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US10/206,286
• Publication Number:
  US 20040019732A1
• Time in Patent Office: 648 Days
• Field of Search: 710/311, 710/313, 710/110, 710/316, 710/305, 710/38, 370/362
• US Class Current: 710/313
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence

Abstract

A Universal Serial Bus hub apparatus and method is disclosed that is compatible with the On-the-Go (OTG) supplement to the USB 2.0 specification so as to enable dual-role devices (OTG devices) to be connected via a hub. The hub includes a number of ports that are configured to connect the hub to one or more external devices, which may include OTG devices. A controller within the hub controls operations therein. The hub also includes a port switching device controlled by the controller for selectively allowing one of the number of ports to act as a host port and the other remaining ports to act as device ports.

Claims

1. A Universal Serial Bus hub apparatus comprising:

a plurality of ports configured to connect the USB hub apparatus to one or more external devices;

a controller device; and

a port switching device coupled to the controller device and the plurality of ports and controlled by the controller device for selectively connecting any one of the plurality of ports to serve as a host port and the other ones of the plurality of ports to serve as device ports.

2. The apparatus according to claim 1, wherein each of the plurality of ports comprises an A-type of Universal Serial Bus port.

3. The apparatus according to claim 2, further comprising:

an override port comprising a B-type of Universal Serial Bus port allowing connection of a personal computer to obtain host control.

4. The apparatus according to claim 1 further comprising:

a collision detector and control device configured to detect signal collisions occurring between signals received by the plurality of ports acting as device ports from the external devices that are being transmitted to the host port and mitigate the collisions by selectively switching a multiplexing circuit.

5. The apparatus according to claim 1, wherein the controller detects when the port acting as host port is idle for a predetermined period and controls the port switching device to connect the USB hub apparatus as a host control.

6. The apparatus according to claim 1, wherein the controller comprises a microcontroller, a USB host controller and a USB peripheral controller.

7. The apparatus according to claim 6, wherein the microcontroller is configured to communicatively connect the USB host controller to the port switching device during a start-up of the USB hub apparatus.

8. The apparatus according to claim 7, wherein the microcontroller is configured to detect when a request by an external device to act as host control is received via one of the plurality of ports to which the external device is attached and control the switching device to reconfigure the switching device such that all other ports of the plurality ports are device ports in response to the detection of the request.

9. The apparatus according to claim 8, wherein the microcontroller is configured such that when a USB peripheral controller port acting as host port is idle for a predetermined period the microcontroller controls the port switching device to connect the USB hub apparatus as a host control.

10. The apparatus according to claim 1 wherein the USB hub apparatus is configured to operate according to the On-the-Go supplement to the USB 2.0 specification and the ports are configured to be connectable to On-the-Go dual-role devices.

11. The apparatus according to claim 1, wherein the controller is configured to assume host control during the occurrence at least one of start up of the USB hub apparatus, idleness of a current host device and transfer of host control between two peripheral devices.

12. A USB communication system comprising:

one or more dual-role peripheral devices; and

a hub apparatus comprising;

a plurality of ports configured to connect the hub apparatus device to the one or more peripheral devices;

a controller device; and

a port switching device coupled to the controller device and the plurality of ports and controlled by the controller device for selectively connecting any one of the plurality of ports to serve as a host port allowing a dual-role peripheral of the one or more dual-role peripheral device to assume host control and the other ones of the plurality of ports to serve as device ports.

13. The system according to claim 12, wherein each of the plurality of ports comprises an A-type of Universal Serial Bus port.

14. The system according to claim 13, further comprising:

an override port comprising a B-type of Universal Serial Bus port allowing connection of a personal computer to obtain host control.

15. The system according to claim 12 further comprising:

a collision detector and control device configured to detect signal collisions occurring between signals received by the plurality of ports acting as device ports from the external devices that are being transmitted to the host port and mitigate the collisions by selectively switching a multiplexing circuit.

16. The system according to claim 12, wherein the controller detects when the port acting as host port is idle for a predetermined period and controls the port switching device to connect the hub apparatus as a host control.

17. The system according to claim 12, wherein the controller comprises a microcontroller, a USB host controller and a USB peripheral controller.

18. The system according to claim 17, wherein the microcontroller is configured to communicatively connect the USB host controller to the port switching device during a start-up of the hub apparatus.

19. The system according to claim 18, wherein the microcontroller is configured to detect when a request by an external device to act as host control is received via one of the plurality of ports to which the external device is attached and control the switching device to reconfigure the switching device such that all other ports of the plurality ports are device ports in response to the detection of the request.

20. The system according to claim 19, wherein the microcontroller is configured such that when a USB peripheral controller port acting as host port is idle for a predetermined period the microcontroller controls the port switching device to connect the hub apparatus as a host control.

21. The system according to claim 12 wherein the hub apparatus is configured to operate according to the On-the-Go supplement to the USB 2.0 specification and the ports are configured to be connectable to On-the-Go dual-role devices.

22. The system according to claim 12, wherein the controller is configured to assume host control during the occurrence at least one of start up of the hub apparatus, idleness of a current host device and transfer of host control between two peripheral devices.

23. A method of operating a USB hub having a plurality of ports and a hub controller for controlling routing of the ports, the method comprising:

operating the hub as a host device having host control during a start-up period;

determining using the hub controller which of the plurality of ports are connected to corresponding external devices and assigning addresses to those devices;

enabling a host negotiation protocol on the external devices; and

transferring host control from the hub to a first external device connected to a first port of the plurality of ports when a request for host control is received by the hub controller from the first external device via the first port, the first port being any of the plurality of ports.

24. The method according to claim 23 further comprising:

transferring host control back to the hub controller from the first external device after an external device to which host control was transferred no longer requests host control according to a predetermined condition.

25. The method according to claim 24, wherein the predetermined condition comprises when no communication occurs on the port to which the first external device is connected indicating that the first external device is idle.

26. The method according to claim 24, wherein the predetermined condition comprises when a signal from the first external device is received by the hub indicating that the external device no longer requests host control.

27. The method according to claim 23, further comprising:

transferring host control to a second external device connected to a second port of the plurality of ports when a signal requesting host control is received by the hub via the second port from the second external device.

28. The method according to claim 23, further comprising:

transferring host control to an override port of the plurality of ports when a personal computer is connected to the override port.