The semiconductor device includes a command generator, an information signal storage unit, a termination signal generator and a code generator. The command generator generates a mode register write command signal, a start command signal and a termination command signal from external command signals. The information signal storage unit extracts information signals from the external command signals to store the information signals and output the information signals. The termination signal generator generates a termination signal in response to the information signals. The code generator generates code signals to control a timing of a control signal.