UNIVERSAL SERIAL BUS INTERFACE APPARATUS

摘要

A USB(Universal Serial Bus) interface device is provided to enable a user to select/use a desired device between more than two USB devices connected to one USB port without using an expensive USB hub. A USB 2.0 physical layer(110) interface transfers data by fitting a signal level between a PC(20) and a USB link(120), which is placed between the USB 2.0 physical layer interface and an SD(Secure Digital)/ MMC(Multimedia Memory Card) host(130). The SD/MMC host transfers the data between an SD/MMC card, and the PC or a terminal(30) at a rear side of the USB link. An SD/MMC bus switch(140) connects the SD/MMC card with the terminal or the SD/MMC host by a main controller(150). The main controller connects the SD/MMC card with the terminal or the SD/MMC host by controlling the SD/MMC bus switch, realizes data communication between the SD/MMC card, and the PC or the terminal by controlling the SD/MMC host, and realizes the data communication between the USB 2.0 physical layer interface and the SD/MMC host according to a USB communication protocol by controlling the USB link.