An electronic device includes a memory device including first and second ranks, and a system-on-chip that exchanges data with the memory device. The system-on-chip loads a first training code to the first rank and performs a first training operation on the second rank using the first training code loaded to the first rank, and loads the first training code to the second rank and performs a second training operation on the first rank using the first training code loaded to the second rank. The system-on-chip generates a first reference voltage for sampling output data of the first rank, and generates a second reference voltage for sampling output data of the second rank. The first and second reference voltages are generated based on a first result of performing the first training operation on the second rank, and a second result of performing the second training operation on the first rank.