# US 8,572,420 B2 · Power managed USB for computing applications using a controller > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,572,420 B2 - Document ID: US8572420B2 - Status: Granted - Kind: B2 - Application number: 11/071,961 - Filed: 2005-03-04 - Published: 2005-07-21 - Granted: 2013-10-29 - Earliest claimed: 2004-01-20 - Assignees: Standard Microsystems Corporation - Applicants: Drew J. Dutton; James R. MacDonald; Henry Wurzburg - Inventors: Drew J. Dutton; James R. MacDonald; Henry Wurzburg - Web page: https://patentgrep.com/patent/US8572420B2 ## CPC - G06K 19/07732: {the record carrier having a housing or construction similar to well-known portable memory devices, such as SD cards, USB or memory sticks (housings for electrical equipment in general, see H05K5/02)} - G06K 7/0013: {by galvanic contacts, e.g. card connectors for ISO-7816 compliant smart cards or memory cards, e.g. SD card readers (connectors in general H01R13/00; connectors for SIM cards used in mobile phones or the like H04B1/3816)} - G06K 7/0086: {the connector comprising a circuit for steering the operations of the card connector} - G06K 19/0701: {at least one of the integrated circuit chips comprising an arrangement for power management} - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract In various embodiments, a computer system may include a computer controller to send and/or receive sideband signals to/from a USB device. In some embodiments, the USB device may include a USB controller to send/receive sideband signals to/from the computer controller. The computer controller and USB controller may allow communications between the computer system and the USB device when either of the computer system or USB device is in a low power state. The sideband signal sent between the computer system and the USB device may trigger the other of the computer system or USB device to enter a normal power state. In some embodiments, the computer controller and/or USB controller may be further coupled to a memory to buffer data to be sent to the computer system or USB device after the computer system or USB device returns to a normal power state. ## Claims ### Claim 1 An apparatus, comprising: a computer system, comprising: a central processing unit (CPU); a computer controller coupled with the central processing unit, wherein the computer controller comprises a USB host controller and a separate controller for handling said sideband signal; wherein the computer controller is configured to communicate with a Universal Serial Bus (USB) device coupled to the computer system via a first medium and a second medium, wherein the USB device is external to the computer system, wherein the computer system and USB device are coupled to perform USB communications using the first medium and to perform sideband communications using the second medium, wherein the first medium and the second medium are different; wherein the computer system is configured to communicate the sideband signal to the USB device over a sideband signal line when the sideband signal line is coupled to the computer system; and wherein the computer system and USB device are operable to use the sideband signal line to trigger the other of the computer system or USB device to return to a normal power state from a low power state and wherein during the low power state the separate controller buffers data received from the USB device until the computer system returned to the normal power state. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the computer system is configured to buffer data to send to the USB device. ### Claim 3 A method, comprising: placing a Universal Serial Bus (USB) device in a low power state; sending a sideband signal to the USB device from a computer controller coupled to a computer system comprising a central processing unit to trigger the USB device to enter a normal power state, wherein the USB device is external to the computer system, wherein said sending is performed over a first medium; and wherein the USB device enters the normal power state after receiving the sideband signal, wherein data to be sent to the USB device after sending the sideband signal but before the USB device entered the normal power state is buffered; after the USB device enters the normal power state, performing USB communications between the USB device and said central processing unit over a second medium that is different than the first medium, wherein the computer system sending the buffered data to the USB device when the USB device is in the normal power state. ### Claim 4 (depends on 3) The method of claim 3, wherein the USB device is coupled to a USB controller; wherein the USB controller is part of the computer controller. ### Claim 5 (depends on 3) The method of claim 3, wherein the computer system sends the sideband signal via said computer controller to the USB device when an indication is received from a user. ### Claim 6 (depends on 3) The method of claim 3, further comprising: placing the computer system in a low power state; placing the computer system in a normal power state; and wherein the computer system enters the normal power state after receiving an indication from a user. ### Claim 7 (depends on 6) The method of claim 6, wherein the computer controller sends the sideband signal to the USB device when the computer system enters the normal power state. ### Claim 8 (depends on 6) The method of claim 6, wherein the indication from the user includes using a device coupled to the computer system. ### Claim 9 A method, comprising: providing a computer system having a central processing unit and a controller coupled with the central processing system; sending a sideband signal to the controller from a Universal Serial Bus (USB) device to trigger the computer system to enter a normal power state from a low power state, wherein the USB device is external to the computer system, and wherein said sending the sideband signal is performed over a first medium; wherein the computer system enters the normal power state after receiving the sideband signal; after the computer system enters the normal power state, performing USB communication with the computer system over a second medium that is different than the first medium; the USB device buffering data to send to the computer system while the computer system is in the low power state; and the USB device sending the buffered data to the computer system when the computer system enters the normal power state. ### Claim 10 (depends on 9) The method of claim 9, wherein the controller comprises a USB controller and a separate computer controller; wherein the computer controller is configured to receive the sideband signal from the USB device. ### Claim 11 (depends on 9) The method of claim 9, wherein the USB device sends the sideband signal to the controller when an indication is received from a user. ### Claim 12 (depends on 9) The method of claim 9, further comprising: placing the USB device in a low power state; placing the USB device in a normal power state; and wherein the USB device enters the normal power state after receiving an indication from a user. ### Claim 13 (depends on 12) The method of claim 12, wherein the USB device sends the sideband signal to the controller when the USB device enters the normal power state. ### Claim 14 (depends on 12) The method of claim 12, wherein the indication from the user includes using the USB device. ### Claim 15 An apparatus, comprising: a computer system, comprising: a processor; a computer controller coupled to the processor; and a memory medium coupled to the processor; a Universal Serial Bus (USB) communication medium coupled to the computer system, wherein the USB communication medium is operable to transmit USB signals from the computer system to a USB device, wherein the USB device is external to the computer system; a sideband signal line coupled to the computer controller, wherein the sideband signal line is a separate communication medium than the USB communication medium and wherein the sideband signal line is operable to communicate a sideband signal to the USB device from the computer controller; and wherein the memory medium is operable to buffer data to send from the computer system to the USB device when the USB device is in a low power state; and wherein the computer system is operable to send the buffered data to the USB device after the USB device enters a normal power state; wherein the computer system is operable to trigger the USB device to enter the normal power state from the low power state by sending the USB device a sideband signal over the sideband signal line. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the computer controller is operable to send the sideband signal over the sideband signal line and wherein the computer controller is a separate controller than a USB host controller on the computer system coupled to the USB communication medium. ### Claim 17 (depends on 1) The apparatus of claim 1, wherein the USB device is operable to electrically disconnect from the computer system over a USB communication medium prior to the computer system entering the low power state; wherein the USB device is operable to receive the sideband signal from the computer system over the sideband signal line while the USB device is in a low power state; wherein the USB device is operable to electrically reconnect to the computer system over the USB communication medium when the USB device receives the sideband signal; and wherein the USB communication medium is configured to communicate USB signals between the USB device and the computer system. ### Claim 18 (depends on 3) The method of claim 3, further comprising: the USB device electrically disconnecting from the computer system over a USB communication medium prior to the USB device entering the low power state; and the USB device electrically reconnecting to the computer system over the USB communication medium when the USB device receives the sideband signal from the computer system over a sideband signal line triggering the USB device to enter the normal power state; and wherein the USB communication medium is configured to communicate USB signals between the USB device and the computer system. ### Claim 19 (depends on 3) The method of claim 3, wherein while the USB device is in the low power state, the USB device does not cause system activity on a Peripheral Component Interconnect (PCI) bus of the computer system. ### Claim 20 (depends on 9) The method of claim 9, further comprising: the USB device electrically disconnecting from the computer system over a USB communication medium prior to the computer system entering the low power state; and the computer system electrically reconnecting to the USB device over the USB communication medium when the computer system receives the sideband signal from the USB device over a sideband signal line triggering the computer system to enter the normal power state; and wherein the USB communication medium is configured to communicate USB signals between the USB device and the computer system. ### Claim 21 (depends on 9) The method of claim 9, wherein while the USB device is in the low power state, the USB device does not cause system activity on a Peripheral Component Interconnect (PCI) bus of the computer system. ### Claim 22 (depends on 1) The apparatus of claim 1, wherein the second medium comprises a wireless medium. ### Claim 23 (depends on 1) The apparatus of claim 1, wherein the second medium comprises a radio frequency medium. ### Claim 24 (depends on 3) The method of claim 3, wherein the first medium comprises a wireless medium. ### Claim 25 (depends on 3) The method of claim 3, wherein the first medium comprises a radio frequency medium. ### Claim 26 (depends on 9) The method of claim 9, wherein the first medium comprises a wireless medium. ### Claim 27 (depends on 9) The method of claim 9, wherein the first medium comprises a radio frequency medium. ### Claim 28 (depends on 15) The apparatus of claim 15, wherein the sideband signal line comprises a wireless medium. ### Claim 29 (depends on 15) The apparatus of claim 15, wherein the sideband signal line comprises a radio frequency medium.