Integrated circuit for a flexible disk drive capable of always

Abstract

In an integrated circuit for use in controlling a flexible disk drive for driving a flexible disk loaded therein, a power on reset circuit produces a reset signal after a predetermined time duration elapses where a power supply voltage is stable from a time when a power supply is applied. The power on reset circuit comprises a voltage detecting circuit for detecting a power supply voltage to produce a voltage detected signal and a delay circuit for producing, responsive to the voltage detected signal, the reset signal after the predetermined time duration elapses. Disposed between a selectable function circuit and a logic circuit, an output holding circuit holds output signals of the selectable function circuit as held signals and supplies the held signals to the logic circuit. The output holding circuit consists of two D-type flip-flops which are disposed in correspondence with two output signal lines of a logical circuit.