Apparatus, memory device, and method for storing multiple parameter codes for operation parameters

A method of controlling a memory device, the method comprising:

• storing a first parameter code used to set a first operating condition for one operation parameter in a first register of a mode register of the memory device;
• storing a second parameter code used to set a second operating condition for the one operation parameter in a second register of the mode register, wherein the second parameter code is expressed as an offset value from the first parameter code;
• storing a first control code for selecting the first parameter code in a third register of the mode register;
• storing a second control code for selecting the second parameter code in a fourth register of the mode register;
• setting the first operating condition as a current operating condition of the memory device by using the first parameter code for the one operation parameter;
• and
• setting the second operating condition as the current operating condition by using the first parameter code and the second parameter code for the one operation parameter.

A memory controller comprising:

• a register control word (RCW) configured to include information of a mode register set (MRS) of a memory device, the information of the MRS including a control parameter indicating that the memory device supports a decision feedback equalizer (DFE) quantity operation of data (DQ) pins of the memory device;
• and
• a training circuit configured to perform training of the DFE quantity operation and determine a global operation parameter and a per-pin operation parameter of the DFE quantity operation, the global operation parameter associated with the DQ pins and the per-pin operation parameter associated with the respective DQ pins,
• wherein the memory controller pre-drives the DQ pins to logic low before performing the training.