Abstract: A compensated-clock generating circuit that complies with USB specifications includes an oscillating circuit that generates clock pulses; a counting circuit that counts the number of clock pulses from the oscillating circuit based upon a regular prescribed signal in accordance with a USB downstream signal; and a frequency compensation value generating circuit that compares the value counted by the counting circuit and a prescribed reference value and obtaining a compensation value. The oscillation frequency of the oscillating circuit is corrected to a prescribed value in response to receipt of the compensation value from the frequency compensation value generating circuit. Compensation is applied based upon a highly accurate signal that is based upon USB specifications, thereby making it possible to generate pulses of higher accuracy even if the accuracy of the oscillation frequency per se of the oscillator in the oscillation circuit is low.

Abstract: A USB-HUB device in which a request for a device connected to a port of the USB-HUB device may be executed by commonly using a serial interface engine of the HUB device has been disclosed. A USB-HUB device (1) may include a HUB address register (124), a HID address register (125), a first comparator (123), a second comparator (113), a virtual port control unit (18) and a HID request processing unit (131). A HID address register (125) may store a HID address. A first comparator (123) may compare a value of a HUB address register (124) with an address field of a supplied token packet. A second comparator (113) may compare a value of a HID address register (125) with an address field of the supplied token packet. A virtual port control unit (18) may indicate a status of a port to which a device (3) may be virtually connected. A HID processing unit (131) may perform a process in response to a request for the device (3).

Abstract: A USB-HUB device in which a request for a device connected to a port of the USB-HUB device may be executed by commonly using a serial interface engine of the HUB device has been disclosed. A USB-HUB device (1) may include a HUB address register (124), a HID address register (125), a first comparator (123), a second comparator (113), a virtual port control unit (18) and a HID request processing unit (131). A HID address register (125) may store a HID address. A first comparator (123) may compare a value of a HUB address register (124) with an address field of a supplied token packet. A second comparator (113) may compare a value of a HID address register (125) with an address field of the supplied token packet. A virtual port control unit (18) may indicate a status of a port to which a device (3) may be virtually connected. A HID processing unit (131) may perform a process in response to a request for the device (3).

Abstract: A circuitry for controlling a response speed of a phase locked loop circuit includes a response speed switching circuit having at least one resistive element with a resistance; and a switching operation control circuit being connected to a phase comparator in the phase locked loop circuit for receiving output signals from the phase comparator, and the switching operation control circuit being also connected to the response speed switching circuit for transmitting selected one of first and second switching control signals to the response speed switching circuit, so that if the response speed switching circuit receives the first switching control signal from the switching operation control circuit, then the response speed switching circuit becomes connected to the phase locked loop circuit, whereby the at least one resistive element becomes connected in parallel to the phase locked loop circuit so as to place the phase locked loop circuit into a high speed response state, and so that if the response speed switc