Usb device and its control method



【課題】ハブ種別によらず且つ電池切れ等を引き起こすことなくUSB接続をを確立及び継続できるようにする。 【解決手段】USBデバイス20をUSBホスト10に接続した直後に、ホスト側USBドライバ12とデバイス側USBドライバ22との間で、ネゴシエーションを含む初期化シーケンスを実行する。ネゴシエーションの際にデバイス20からホスト10に渡すコンフィギュレーションデータは、デバイス側の所要電流値を示すMaxPowerフィールドを含む。デバイス20は、MaxPower値が異なる複数通りのコンフィギュレーションデータを逐次ホスト10に送信する。デバイス20のUSB制御モジュール25は、デバイス20における消費電力が、許可されたコンフィギュレーションにおけるMaxPower値に相当する電力値以下の消費電力となるよう、且つ通信制御モジュール23に対してはPHSにおける通信速度を、CPU管理モジュール26に対してはクロック速度を指令する。 【選択図】    図1
PROBLEM TO BE SOLVED: To establish and continue USB connection independently of the kind of hub and without causing battery runout, etc. SOLUTION: Just after a USB device 20 is connected to a USB host 10, an initialization sequence including negotiation is executed between a host-side USB driver 12 and a device-side USB driver 22. Configuration data to be delivered from the device 20 to the host 10 during the negotiation include a maximum power field expressing a current value required on the device side. The device 20 sequentially transmits a plurality of kinds of configuration data different in maximum power value to the host 10. A USB control module 25 of the device 20 gives a command on communication speed in a PHS to a communication module 23 while it gives a command on clock speed to a CPU management module 26, so that electric power consumption in the device 20 is equal to or less than a power value equating to the maximum power value in a permitted configuration. COPYRIGHT: (C)2004,JPO




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Cited By (8)

    Publication numberPublication dateAssigneeTitle
    JP-2012514874-AJune 28, 2012日本電気株式会社通信デバイス
    JP-2014044549-AMarch 13, 2014Buffalo Inc, 株式会社バッファロー情報処理システム及び外部機器
    KR-100742342-B1July 25, 2007삼성전자주식회사신호 송신장치의 송신 에러를 줄일 수 있는 신호 수신장치
    US-7653772-B2January 26, 2010Sharp Kabushiki KaishaControl system, electronic device and image forming apparatus
    US-7818469-B2October 19, 2010Renesas Technology Corp.USB device and peripheral device changing functional module to activate in accordance with descriptor
    US-8423809-B2April 16, 2013Sony CorporationPower consumption measuring and power transmission monitoring for data transfer
    US-8700940-B2April 15, 2014Nec CorporationSmart card able to renegotiate the maximum power supplied to the smart card from a mobile device
    US-9596341-B2March 14, 2017Lenovo Innovations Limited (Hong Kong)Smart card and mobile device using parameters included in an ATR signal and a terminal capabilities signal to indicate whether a maximum power supply value for the smart card can be renegotiated