Semiconductor memory device, control method, and memory system

A control method for controlling a memory cell array having a word line, comprising:

• programming data in a first memory cell provided in the word line, the programming including changing a threshold voltage of the first memory cell to a voltage according to data;
• and
• reading the data from the first memory cell, the reading including measuring the threshold voltage and determining the data on the basis of the measured threshold voltage, the data including first data of a bit and second data of a bit, the program of the second data being executed after the program of the first data,
• wherein in a case where the first data are a target of read, the reading is performed such that a determination as to whether the second data are programmed in the first memory cell or not on the basis of a flag is performed, and in a case where the second data is not programmed in the first memory cell, the measuring of the threshold voltage is aborted.

A memory system comprising:

• a memory controller;
• and
• a semiconductor memory device including a memory cell array including a memory cell, a first circuit that executes program and read, and a second circuit that controls the first circuit, the program being processing for changing a threshold voltage of the memory cell to a voltage according to data, the data including first data of one bit and second data of one bit, the program of the second data being executed after the program of the first data, the read being processing for determining the first data or the second data by measuring the threshold voltage,
• wherein the memory controller transmits a read command including a read target to the semiconductor memory device,
• the second circuit manipulates a flag in accordance with execution of the program of the second data, and in a case where the read target indicates a location of the second data, the second circuit refers to the flag, and in a case where the flag indicates non-execution of the program of the second data, the second circuit aborts the measuring before the measuring of the threshold voltage is completed and outputs a fixed value.