| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a USB (Universal Serial Bus) interface for a device capable of surely performing a communication just after a bus reset cancellation even when a host issues a bus reset signal immediately after recognizing the power supply of the device. <P>SOLUTION: A USB controller 1 can control the pull-up of a signal line D+ for reporting the power supply of the device to the host through a switching element Q1. When the power of the device is supplied, the CPU 3 of the device initializes itself and initializes the USB controller 1. During the initialization, the USB controller 1 maintains the switching element Q1 to be OFF as an initial state, and forms a pseudo power OFF state to the host. Then, when the initialization of the USB controller 1 is completed, the USB controller 1 turns the switching element Q1 ON to pull up the signal line D+. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
