Method for entering powersave mode of USB hub

• US 6,272,644 B1
• Filed: 01/06/1999
• Issued: 08/07/2001
• Est. Priority Date: 01/06/1999
• Status: Expired due to Term

• Current Assignee: Socionext Inc.
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Lin, Liang, Afshar, Eskandar, Urade, Masakazu
• Primary Examiner(s): Shin, Christopher B.
• Application Number:
  US09/226,778
• Time in Patent Office: 944 Days
• Field of Search: 710/1-4, 710/52, 710/62-64, 710/100-101, 710/126-131, 713/300, 713/310, 713/320, 713/330, 713/340, 713/600, 713/601
• US Class Current: 713/320
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode

Abstract

A method of controlling a USB hub by a microcontroller, comprising the steps of sending a suspend request to the microcontroller from the USB hub; sending a stop clock request from the microcontroller to the USB hub in response to the suspend request; and stopping the USB hub controller clock in response to the suspend request; entry into a powersave mode by the microcontroller in response to the suspend request.

Claims

1. A method of controlling a USB hub by a microcontroller, comprising:

sending a suspend request to the microcontroller from the USB hub;

sending a stop clock request from the microcontroller to the USB hub in response to the suspend request; and

stopping the USB hub controller clock in response to the stop clock request;

entry into a powersave mode by the microcontroller in response to the suspend request.

2. The method of controlling a USB hub of claim 1, wherein a host computer sends a suspend request to the USB hub before the hub sends a suspend request to the microcontroller.

3. The method of controlling a USB hub of claim 1, wherein the microcontroller suspends all I²C signals before sending the stop clock request.

4. The method of controlling a USB hub of claim 1, further comprising:

sending a resume request to the USB hub from the microcontroller;

in response to the resume request de-asserting the suspend request sent from the hub to the microcontroller;

in response to the de-assertion of the suspend request de-asserting the stop clock request sent from the microcontroller to the USB hub;

restarting the clock of the USB hub in response to the de-asserting of the stop clock request; and

exiting from the powersave mode by the microcontroller in response to the de-asserting of the suspend request.

5. The method of controlling a USB hub of claim 3, further comprising the step of sending a resume request to the hub from the microcontroller before the USB hub sends a resume request to the microcontroller.

6. The method of controlling a USB hub of claim 5, wherein the microcontroller receives an external wake up signal before the microcontroller sends a resume request to the USB hub.

7. The method of controlling a USB hub of claim 6, wherein the external wake up signal is an IR signal received from a hand held device.

8. A method of controlling a USB hub, the USB hub including a hub controller, a hub repeater and a microcontroller interface, comprising:

sending a SUSPEND signal to a microcontroller in response to a suspend request from a host computer connected to the hub controller;

sending a STOPCLK signal to the hub controller; and

initiating a STOP mode in the hub controller in response to the received STOPCLK signal.

9. The method of controlling a USB hub of claim 8, further comprising:

sending a RESUMEI signal to the hub controller;

stopping the SUSPEND signal sent to the microcontroller in response to the received RESUMEI signal;

stopping the sending of the RESUMEI signal;

stopping the sending of the STOPCLK signal sent from the microcontroller in response to the stopping of the SUSPEND signal; and

restarting the hub controller in response to the stopping of the STOPCLK signal.