| 摘要 |
An identifying circuit is connected between a Universal Serial Bus (USB) interface and a controller. The identifying circuit includes first and second resistors, and a diode. When a power adapter is connected to the USB interface, a negative data pin of the USB interface is floating, an identify pin of the controller receives a high level signal to determine that the power adapter is connected to the USB interface. When a computer is connected to the USB interface, the negative data pin of the USB interface outputs a low level signal, the identify pin of the controller receives a low level signal to determine that the USB interface is connected to the computer.
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