A direction setting pin DIR receives a direction signal ROT that indicates the rotational direction of the stepping motor. A clock pin CLK receives a clock signal CLK that indicates the rotational direction of the stepping motor. A logic circuit generates a first internal signal and a second internal signal that respectively indicate the states of the first H-bridge circuit and the second H-bridge circuit according to the direction signal ROT and the clock signal CLK. When the clock signal CLK remains in a predetermined state for a predetermined judgment time, the logic circuit transits to a predetermined mode.