An arbitration system and method is disclosed. The apparatus includes a first and a second memory devices, and a resistor coupled in common to the first and second memory devices, the first memory device includes a first calibration circuit configured to perform a first calibration operation responsive, at least in part, to an external calibration command, the first calibration operation being performed based on the resistor, and the second memory device includes a second calibration circuit configured to perform a second calibration operation responsive, at least in part, to the external calibration command, the second calibration operation being performed based on the resistor after the first calibration operation has finished.