The power consumption of a control device or a data processing system is reduced. Safety is enhanced. An electronic device is operated in a simple way. A control device includes an arithmetic circuit, an input unit, and a power management unit. The input unit includes a sensor element. The power management unit has a function of controlling supply and shutdown of power to the arithmetic circuit. The power management unit has a function of supplying power to the arithmetic circuit in response to a detection signal output from the sensor element. The sensor element includes one or more selected from an acceleration sensor, an angular velocity sensor, and a magnetic sensor. The arithmetic circuit includes a register. The register includes a first circuit and a second circuit. The register has a function of storing, in the second circuit, first data stored in the first circuit in a period during which the power management unit supplies power to the arithmetic circuit and retaining the first data, in a period during which the power management unit stops power supply to the arithmetic circuit. The arithmetic circuit has a function of generating second data with use of signal data output from the sensor element and the first data.