Nonvolatile memory system, semiconductor memory and writing method
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Abstract
A nonvolatile semiconductor memory recovers variation in the threshold of a memory cell due to disturbance related to a word line. The nonvolatile memory continuously performs many writing operations without carrying out single-sector erasing after each writing operation, performing the additional writing operations quicker than the usual writing operation, and lightening the burden imposed on software for use in additional writing. The data stored in a designated sector is read out before being saved in a register, and the selected sector is subjected to single-sector erasing when a predetermined command is given. Then write expected value data is formed from the saved data and data to be additionally written, completing the writing operation.
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Citations
43 Claims
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1-31. -31. (canceled)
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32. A nonvolatile memory comprising:
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a plurality of nonvolatile memory cells each of which has an arbitrary one of a programmed state and an erased state;
a plurality of input/output terminals;
a command decode circuit which is capable of decoding an arbitrary one of commands received via said plurality of input/output terminals;
a voltage generator;
a plurality of word lines; and
a control circuit, wherein in performing a program operation in response to decoding a write command, which is accompanied with address information and data, by said command decode circuit, said control circuit controls selection of one word line in accordance with said address information, supply of a program voltage generated by said voltage generator to said one word line, and storage of said data into ones of said nonvolatile memory cells coupled to said one word line, wherein all of said ones of said nonvolatile memory cells coupled to said one word line have said erased state before performing said program operation, and wherein another one of said nonvolatile memory cells coupled to said one word line has said programmed state before performing said program operation and has said programmed state after performing said program operation. - View Dependent Claims (33, 34, 35, 36, 37)
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38. A nonvolatile memory comprising:
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a plurality of nonvolatile memory cells, each of which has an arbitrary one of a programmed state and an erased state;
a plurality of input/output terminals;
a command register which is capable of storing an arbitrary one of commands received via said plurality of input/output terminals;
a voltage generator;
a plurality of word lines; and
a sequencer, wherein in performing a program operation in response to a write command, which is accompanied with address information and data, received via said input/output terminals, said sequencer controls selection of one word line in accordance with said address information, supply of a program voltage generated by said voltage generator to said one word line, and moving of states of said nonvolatile memory cells coupled to said one word line from said erased state to said programmed state in accordance with said data, and wherein said sequencer allows performing a first program operation in response to said write command accompanied with a first address as said address information, which first address is for selecting first ones of said plurality of nonvolatile memory cells coupled to a first word line, after performing a second program operation in response to said write command accompanied with a second address as said address information, which second address is for selecting second ones of said plurality of nonvolatile memory cells coupled to said first word line, without an erase operation in response to an erase command for moving states of said first ones of said nonvolatile memory cells into said erased state. - View Dependent Claims (39, 40, 41, 42, 43)
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Specification