Electronic device to perform enumeration without power request to an external device when electronic device is on
View Patent ↗An electronic device can communicate with an external device according to a predetermined method. The electronic device includes a power switch operable to receive an operation for switching on and off the electronic device, a detector operable to detect a connection between the electronic device and the external device according to the predetermined method, and a requestor operable to request the external device to supply power. When the detector detects the connection between the electronic device and the external device with the power switch being ON, the requestor does not request the external device to supply the power in an establishing process for establishing the communication with the external device. When the detector detects the connection between the electronic device and the external device and the power switch is switched from ON into OFF, the requestor requests the external device to supply the power in the establishing process.
1. An electronic device capable of communicating with an external device according to a predetermined method, comprising:
a power switch operable to receive an operation for switching on and off the electronic device, the power switch being turned off when receiving the operation for switching off and turned on when receiving the operation for switching on;
a detector operable to detect a connection between the electronic device and the external device according to the predetermined method; and
a requestor operable to request the external device to supply power, wherein
when the detector detects the connection between the electronic device and the external device with the power switch being ON, the requestor does not request the external device to supply the power during an establishing process for establishing the communication with the external device,
when the detector detects the connection between the electronic device and the external device and the power switch is switched from ON to OFF, the requestor requests the external device to supply the power during the establishing process,
the establishing process for establishing the communication with the external device is via a USB enumeration, and
when the detector detects the connection between the electronic device and the external device and the power switch is switched from ON to OFF, the requestor requests the external device to supply the power during the USB enumeration by a transmission of a predetermined configuration descriptor which includes information requesting power.
2. The electronic device according to claim 1 , wherein the requestor requests the external device an amount of supply which enables the charging of a battery which supplies power to respective units of the electronic device.
3. The electronic device according to claim 2 , further comprising a charger operable to charge the battery with the power supplied from the external device when the requestor requests the external device to supply the power during the establishing process and the communication between the electronic device and the external device is established.
4. The electronic device according to claim 2 , further comprising a display unit operable to display information representing that the battery cannot be charged when the requestor requests the external device to supply the power in the establishing process and the communication between the electronic device and the external device is not established.
5. The electronic device according to claim 1 , wherein the predetermined method is USB standard.
6. The electronic device according to claim 1 , wherein the predetermined configuration descriptor includes information indicating a value of power to be requested from the external device and information indicating a communication class supported by the electronic device.
7. An electronic device capable of communicating with an external device according to a predetermined method, comprising:
a controller; and
a memory storing instructions for configuring the controller, the controller configured to:
detect a connection between the electronic device and the external device; and
when the connection between the electronic device and the external device is detected, send a request for requesting the external device to supply power during an establishing process for establishing the communication with the external device only when power to the electronic device is in an off state, wherein:
the establishing process for establishing the communication with the external device is via a USB enumeration; and
when the connection between the electronic device and the external device is detected, the request to the external device is sent for supplying the power during the USB enumeration by a transmission of a predetermined configuration descriptor which includes information requesting power.
8. The electronic device according to claim 7 , wherein the predetermined configuration descriptor includes information indicating a value of power to be requested from the external device and information indicating a communication class supported by the electronic device.