When a watchdog reset request is input, a power supply controller performs partial reset processing (resetting of a control circuit alone). When restarted by partial reset processing, the control circuit makes a non-volatile memory store a log of the stored contents of a volatile memory. After the log is stored, the control circuit transmits a system reset request to the power supply controller. Based on the system reset request, the power supply controller resets the control circuit, the non-volatile memory, the volatile memory, and reset targets.