Abstract: SOC (System On Chip) for optical mouse with 8-pins is provided. The SOC of the invention has three power pins for coupling a first power voltage, a second power voltage and ground voltage, a driving pin for controlling a light source, an optical sensing array for receiving reflected light, two signal pins for data exchange with a host and two IO pins. For at least five different switches of the optical mouse that receive touch controls of users, each IO pin receives and distinguishes statuses of multiple switches, such that a total pin count of the IO pins is less than a total number of switches.

Abstract: A frequency detecting and converting apparatus comprises a plurality of frequency-dividers, a multiplexer, a pulse width detector, a comparing unit and an encoder. The invention automatically detects the operating frequency of an input clock signal, divides the frequency of the input clock signal by a pre-defined integer according to the detected operating frequency and finally generates an output clock signal with an operating frequency required for an integrated circuit.

Abstract: A frequency detecting and converting apparatus comprises a plurality of frequency-dividers, a multiplexer, a pulse width detector, a comparing unit and an encoder. The invention automatically detects the operating frequency of an input clock signal, divides the frequency of the input clock signal by a pre-defined integer according to the detected operating frequency and finally generates an output clock signal with an operating frequency required for an integrated circuit.