USB DEVICE AND USB CONNECTION SYSTEM

摘要

PROBLEM TO BE SOLVED: To improve availability using a reset operation for recovery of an internal communication fault or the like, by providing a USB device capable of executing the reset operation on the basis of a reset from a host, a host device connected to the USB device, and a USB connection system.SOLUTION: The USB device includes a CPU for executing a control operation of the entire device in a normal mode but also stopping the operation in a power-saving mode and a state monitoring circuit for monitoring the normal mode and the power-saving mode of the CPU and switches between both of the modes by switching of a clock signal supplied to the CPU. In response to reception of a reset signal, the CPU is switched to the normal mode in the case of the CPU being in the power-saving mode and transmits a signal for resetting the CPU and a USB communication means to a reset circuit in the case of the CPU being in the normal mode.