Abstract: A microcomputer has an electric potential control unit, a signal generation unit, and a timing signal generation circuit. The electric potential control unit includes a transistor which controls an electric potential of an input terminal which is energized by a power supply. The signal generation unit includes an input buffer circuit which receives a change in the electric potential of the input terminal and supplies an interrupt signal to a CPU. The timing signal generation circuit generates a timing signal which controls conductivity of a transistor and operates the transistor intermittently. A capacitor is connected to the input terminal.

Abstract: A semiconductor integrated circuit includes an oscillator circuit, which amplifies a signal sent from an oscillator by an amplifier circuit operating with a low power supply voltage for outputting the same. In the oscillator circuit, a threshold voltage of a transfer gate forming a switching element is set to a value lower than a threshold voltage of other transistors so as to reduce an on-resistance of the transfer gate and hence to ensure output of a signal supplied from said oscillator.