A hot plug of pci bus using single chip

PURPOSE: A hot plug controller of a PCI bus is provided to implement a power on/off control, an adaptor card installation sense, a 66MHz operation check, a physical ID and a USB or I2C bus interface function on a single chip so that it can reduce a cost and enhance a reliability. CONSTITUTION: The device comprises an SIU(System Interface Unit, 110), an RU(Register Unit, 120), a PCU(power Control Unit, 130), and a BIU(Bus Isolation Unit, 140). The SIU(110) interfaces with a PCI bus, a USB and an I2C bus. The RU(120), connected to the SIU(110), performs a function of a reset control, a present detection, a 66MHz enable check, an LED control, and a storage of a physical ID data. The PCU(130) switches a power of a PCI slot on or off by controlling an FET power transistor for connecting the system power to the pcI slot. The BIU(140) isolates the signals of the PCI slot from the PCI bus by controlling the RU(120).