METHOD OF MAINTAINING A USB ACTIVE STATE WITHOUT DATA TRANSFER

A USB bus-powered device (32) in Suspend state that requires active bus state power levels, but has no data transfer need, may initiate Resume signaling to return a USB bus segment (31) to active state, without transferring any data across the bus (31). A device driver (24) considers both USB device...

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Hauptverfasser: MULLIS II SAMUEL, FRISBEE MARK STEVEN
Format: Patent
Sprache:eng ; kor
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Zusammenfassung:A USB bus-powered device (32) in Suspend state that requires active bus state power levels, but has no data transfer need, may initiate Resume signaling to return a USB bus segment (31) to active state, without transferring any data across the bus (31). A device driver (24) considers both USB device (32) power needs and data transfer activity in deciding to Globally or Selectively Suspend a bus or bus segment (31). In particular, upon deciding to Suspend a bus or bus segment (31), the device driver (24) queries a USB bus-powered device (32). If the device (32) will require active bus mode power within a predetermined duration, the device (32) will indicate to the device driver (24) to remain an active mode. In this case, the device driver (24) does not direct the USB host (26) to Suspend the bus (31).