Non-volatile multilevel memory cells
The present disclosure includes methods, devices, modules, and systems for operating non-volatile multilevel memory cells. One method embodiment includes assigning, to a first cell coupled to a row select line, a first number of program states to which the first cell can be programmed. The method includes assigning, to a second cell coupled to the row select line, a second number of program states to which the second cell can be programmed, wherein the second number of program states is greater than the first number of program states. The method includes programming the first cell to one of the first number of program states prior to programming the second cell to one of the second number of program states.
1. A method of programming memory cells, the method comprising:
programming a first subset of commonly coupled memory cells to one of a first number (E) of program states;
programming a second subset of the commonly coupled memory cells to one of a second number (O) of program states, wherein O is greater than E;
using a first read margin associated with the first subset of cells; and
using a second read margin associated with the second subset of cells, wherein the first read margin is greater than the second read margin; and
wherein the first number of program states and/or the second number of program states correspond to a respective non-integer number of bits.
2. The method of claim 1 , wherein the method includes combining data stored by a memory cell of the first subset with data stored by an adjacent memory cell of the second subset to represent an integer number of bits.
3. The method of claim 2 , wherein the method includes reading the first and the second subsets of cells together as a group.
4. The method of claim 3 , wherein data stored in the first subset of cells and the second subset of cells corresponds to a page of data.
5. The method of claim 1 , wherein the first subset of cells is interwoven with the second subset of cells such that each memory cell of the first subset is adjacent to a memory cell of the second subset.
6. A method of programming memory cells, the method comprising:
programming a first subset of commonly coupled memory cells to one of a first number (E) of program states;
programming a second subset of the commonly coupled memory cells to one of a second number (O) of program states, wherein O is greater than E;
using a first read margin associated with the first subset of cells; and
using a second read margin associated with the second subset of cells;
wherein the first read margin is greater than the second read margin; and
wherein the first subset of cells and the second subset of cells are read together as a group.
7. The method of claim 6 , wherein data stored in the first subset of cells and the second subset of cells corresponds to a page of data.
8. The method of claim 6 , wherein O is twice E.
9. The method of claim 6 , wherein the first number of program states and/or the second number of program states correspond to a respective non-integer number of bits.
10. A method of programming memory cells, the method comprising:
programming a first subset of commonly coupled memory cells to one of a first number (E) of program states;
programming a second subset of the commonly coupled memory cells to one of a second number (O) of program states, wherein O is greater than E;
using a first read margin associated with the first subset of cells; and
using a second read margin associated with the second subset of cells, wherein the first read margin is greater than the second read margin; and
wherein the first subset of cells is interwoven with the second subset of cells such that each memory cell of the first subset is adjacent to a memory cell of the second subset.
11. The method of claim 10 , wherein the first subset of cells and the second subset of cells are commonly coupled to a row select line.
12. The method of claim 10 , wherein O is twice E.
13. The method of claim 10 , wherein the first number of program states and/or the second number of program states correspond to a respective non-integer number of bits.
14. A method of programming memory cells, the method comprising:
programming a first subset of commonly coupled memory cells to one of a first number (E) of program states;
programming a second subset of the commonly coupled memory cells to one of a second number (O) of program states, wherein O is greater than E; and
programming a third subset of the commonly coupled memory cells to one of a third number (E2) of program states;
wherein the first number of program states and/or the third number of program states corresponds to a respective non-integer number of bits;
wherein the first subset of memory cells are coupled to a first sense line, the second subset of memory cells are coupled to a second sense line, and the third subset of memory cells are coupled to a third sense line, and wherein the first, second, and third sense lines are different sense lines.
15. The method of claim 14 , wherein E2 is greater than O.
16. The method of claim 14 , wherein the method includes reading the first and the third subsets of cells together as a group.
17. The method of claim 16 , wherein data stored in the first and the third subsets of cells corresponds to a page of data.
18. The method of claim 14 , wherein the method includes combining data stored by a memory cell of the first subset with data stored by an adjacent memory cell of the third subset to represent an integer number of bits.
19. The method of claim 18 , wherein the method includes combining data stored by adjacent memory cells of the second subset to represent the integer number of bits.
20. A method of programming memory cells, the method comprising:
programming a first subset of commonly coupled memory cells to one of a first number (E) of program states;
programming a second subset of the commonly coupled memory cells to one of a second number (O) of program states, wherein O is greater than E; and
programming a third subset of the commonly coupled memory cells to one of a third number (E2) of program states;
wherein the first subset of memory cells is programmed prior to programming the second and third subsets;
wherein each of the first, second, and third numbers of program states correspond to a respective number of bits, and wherein a sum of the respective number of bits corresponding to the first number of program states and the respective number of bits corresponding to the third number of program states is twice the respective number of bits corresponding to the second number of program states.
21. The method of claim 20 , wherein the first, second, and third subsets of cells are commonly coupled to a row select line.
22. The method of claim 20 , wherein the method includes programming the second subset prior to programming the third subset.
23. The method of claim 20 , wherein E2 is twice E.
24. A method of programming memory cells, the method comprising:
programming a first subset of commonly coupled memory cells to one of a first number (E) of program states;
programming a second subset of the commonly coupled memory cells to one of a second number (O) of program states, wherein O is greater than E; and
programming a third subset of the commonly coupled memory cells to one of a third number (E2) of program states;
wherein the second subset is programmed prior to the third subset;
wherein the first subset of memory cells are coupled to a first sense line, the second subset of memory cells are coupled to a second sense line, and the third subset of memory cells are coupled to a third sense line, and wherein the first, second, and third sense lines are different sense lines.
25. The method of claim 24 , wherein the first, second, and third subsets of cells are commonly coupled to a row select line.
26. The method of claim 24 , wherein the method includes programming the first subset prior to programming the second and third subsets.
27. The method of claim 24 , wherein the method includes:
using a first read margin associated with the second subset of cells; and
using a second read margin associated with the third subset of cells;
wherein the first read margin is greater than the second read margin.
28. The method of claim 24 , wherein the first number of program states and/or the third number of program states correspond to a respective non-integer number of bits.