US Patent 8006165 Memory controller and semiconductor memory device

A memory controller includes a buffer to which data, which is to be transferred to a memory, is input, an ECC parity generating unit which generates an ECC parity in units of a predetermined data length from the data which is to be transferred to the memory, and a memory interface which adds the generated ECC parity in units of the predetermined data length, and delivers the data with the ECC parity to the memory. When a data length of the data which is to be transferred to the memory is less than the predetermined data length, the ECC parity generating unit regards data of a part that is short of the predetermined data length as “0”, and generates the ECC parity from the data of less than the predetermined data length.