A data processing device, includes a central processing unit configured to operate in accordance with a program; a register capable of setting a first mode and a second mode; a non-volatile memory; a sequencer configured to control the non-volatile memory; and a first clock circuit for supplying a first clock to the central processing unit and the non-volatile memory, wherein the first mode is a mode in which the central processing unit is operated within a first range of an external supply voltage, wherein the second mode is a mode in which the central processing unit is operated within a second range of the external supply voltage, the second range includes the first range and a relatively low voltage lower than the lower limit voltage of the first range.