A central processing unit sets which of the following modes a data processing device is to operate in accordance with a user program. The high-speed operation mode allows operation within a first range in which an external supply voltage is relatively high. The wide voltage range operation mode allows operation within a second range in which the external supply voltage includes the first range and a relatively low voltage range, and an upper limit of a frequency of the first clock in the wide voltage range operation mode is lower than an upper limit of a frequency of the first clock in the high-speed operation mode. The frequency of the first clock in the low power consumption operation mode is lower than the frequency of the first clock in the high-speed operation mode and the frequency of the first clock in the wide voltage range operation mode.