| 摘要 |
<p>The invention is a USB device intended to be connected to a host machine. The USB device may be set into first and second communication modes. The USB device comprises a communication interface able to manage a D+ line, a non volatile memory intended to comprise a preset duration, a timer, and first means capable of activating a first pull up resistor on the D+ line when the USB device is set to the first communication mode. The USB device comprises second, third and fourth means. The second means capable of starting the timer when a USB reset is detected on the D+ line. The third means is capable of switching the USB device to the second communication mode when the timer reaches the preset duration. The fourth means is able to activate a second pull up resistor on the D+ line when the USB device is set to said second communication mode.</p> |
