Semiconductor memory device

A semiconductor memory device comprising:

• a first circuit configured to process data received from and transmitted to an external controller;
• a second circuit configured to execute calibration on the first circuit;
• and
• a control circuit configured to control the second circuit to execute the calibration on the first circuit in response to a calibration command received from the external controller, wherein
• in response to a first calibration command, the control circuit controls the second circuit to execute the calibration on the first circuit, and
• in response to a second calibration command that is received after the first calibration command, the control circuit controls the second circuit to execute the calibration on the first circuit if a first condition is met and to not execute the calibration on the first circuit if the first condition is not met, and
• a command sequence for the first calibration command received from the controller and a command sequence for the second calibration command received from the controller are the same.

A method of managing calibrations executed on an input/output circuit of a semiconductor memory device that performs operations therein in response to commands received from a controller, said method comprising:

• executing a first calibration on the input/output circuit in response to a first calibration command received from the controller;
• in response to a second calibration command that is received after the first calibration command, determining if a first condition is met;
• and
• executing a second calibration on the input/output circuit if the first condition is met but not executing the second calibration on the input/output circuit if the first condition is not met, wherein
• a command sequence for the first calibration command received from the controller and a command sequence for the second calibration command received from the controller are different.

A method of managing calibrations executed on an input/output circuit of a semiconductor memory device that performs operations therein in response to commands received from a controller, said method comprising:

• executing a first calibration on the input/output circuit in response to a first calibration command received from the controller;
• in response to a second calibration command that is received after the first calibration command, determining if a first condition is met;
• and
• executing a second calibration on the input/output circuit if the first condition is met but not executing the second calibration on the input/output circuit if the first condition is not met, wherein
• a command sequence for the first calibration command received from the controller and a command sequence for the second calibration command received from the controller are the same.