A semiconductor system includes a first semiconductor device and a second semiconductor device. The first semiconductor device outputs a chip selection signal, a command signal, and data. The second semiconductor device generates internal data from the data, stores the internal data, and stores the data as pattern data when the chip selection signal is enabled and a write operation is performed according to a logic level combination of the command signal. In addition, the second semiconductor device generates the internal data from the pattern data and stores the internal data without receiving the data when the chip selection signal is enabled and a write copy operation is performed according to a logic level combination of the command signal.