A bus system is provided. A bus system includes a slave functional block and a master functional block. The master functional block transmits a first command to the slave functional block. The slave functional block includes a first bus protector. The first bus protector receives the first command on behalf of the slave functional block and transmits a dummy signal corresponding to the first command to the master functional block in response to the slave functional block being in a state of not being able to receive the first command or not being able to transmit a response signal corresponding to the first command.