Memory life extension system and method

• US 9,268,488 B2
• Filed: 06/04/2014
• Issued: 02/23/2016
• Est. Priority Date: 06/04/2014
• Status: Active Grant

• Current Assignee: Levven Automation Inc.
• Original Assignee: Levven Automation Inc.
• Inventors: Dong, Yi
• Primary Examiner(s): NGUYEN, THAN VINH
• Application Number:
  US14/295,927
• Publication Number:
  US 20150355850A1
• Time in Patent Office: 629 Days
• Field of Search: 711/103, 711/155
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 7/00 Methods or arrangements for processing data by operating upon the order or content of the data handled logic circuits H03K19/00
• CPC Class Codes: G06F 7/76 Arrangements for rearranging, permuting or selecting data according to predetermined rules, independently of the content of the data
• CPC Class Codes: G06F 9/3001 Arithmetic instructions
• CPC Class Codes: G06F 9/3004 to perform operations on memory
• CPC Class Codes: G07C 2009/00253 dynamically, e.g. variable code - rolling code
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks

Abstract

A memory life extension system and method is provided for managing operation of rewritable memory used to store a monotonically increasing sequence of multiple-byte binary values in a set of one or more memory locations in the rewritable memory. A first value is read in from a set of one or more memory locations. On detection of an instruction to store an incremented value, the incremented value is permuted by applying an encoding, in which a value of a least significant bit changes only on every second increment, to two least significant bits of the incremented value. On overflow of a least significant byte as a result of the increment, a cyclic byte-wise shift is applied to the incremented value. The permuted incremented value is then stored in the one or more memory locations.

Claims

1. A method of managing operation of rewritable memory used to store a monotonically increasing sequence of multiple-byte binary values in a set of one or more memory locations in the rewritable memory, the method comprising:

reading in a first value from the set of one or more memory locations;

on detection of an instruction to store an incremented value;

permuting the incremented value by, in combination;

applying an encoding, in which a value of a least significant bit changes only on every second increment, to two least significant bits of the incremented value; and

on overflow of a least significant byte as a result of the increment, applying a cyclic byte-wise shift to the incremented value; and

storing the permuted incremented value in the one or more memory locations.

2. The method of claim 1, wherein the encoding applied to the least significant two bits comprises an encoding of a′

₁=a₁ and a′

₀=a₁a₀, wherein a₀ is an initial value of the least significant bit, a′

₀ is an encoded value of the least significant bit, a₁ is an initial value of a second-least significant bit, and a′

₁ is an encoded value of the second-least significant bit.

3. The method of claim 2, wherein the set of one or more memory locations comprises a plurality of memory locations, and the cyclic byte-wise shift comprises shifting a memory location allocated to a byte of the first value to a next byte of the incremented value.

4. The method of claim 1, wherein the rewritable memory comprises EEPROM.

5. A method of managing operation of rewritable memory used to store a sequence of binary values, the method comprising:

defining an allocation of each one of a plurality of memory blocks in the rewritable memory to a corresponding byte position of a multiple-byte value;

storing a first multiple-byte value in the memory blocks corresponding to the plurality of memory addresses according to the allocation;

reading in the first value from the memory blocks;

incrementing the first value to provide an incremented value;

encoding two least significant bits of the incremented value according to the encoding of a′

₁=a₁ and a′

₀=a₁a₀, wherein a₀ is an initial value of the least significant bit, a′

₀ is an encoded value of the least significant bit, a₁ is an initial value of a second-least significant bit, and a′

₁ is an encoded value of the second-least significant bit;

when the incrementing of the first value does not result in an overflow of a least significant byte, storing the incremented value in the memory blocks according to the allocation;

when the incrementing of the first value results in an overflow of a least significant byte, altering the allocation by cyclically shifting the allocation of the plurality of memory blocks to the corresponding byte positions, and storing the incremented value in the memory blocks according to the allocation as altered.

6. The method of claim 5, wherein storing the incremented value comprises rewriting only those memory blocks corresponding to bytes of the incremented value that are changed.

7. The method of claim 5, further comprising maintaining a mapping of the allocation of the plurality of memory blocks to the corresponding byte positions.

8. The method of claim 5, wherein the rewritable memory comprises EEPROM.

9. The method of claim 5, wherein the first value and the incremented value comprise values in a rolling code algorithm.

10. The method of claim 5, wherein only the least significant bit of the first value is incremented.

11. A method of managing operation of rewritable memory used to store an increment of a stored value, the stored value being represented by multiple bytes, the multiple bytes being stored in a defined set of blocks of the rewritable memory according to a defined byte order, the method comprising:

detecting an instruction to store an incremented value in place of the stored value;

permuting two least significant bits of the incremented value according to the encoding of a′

₁=a₁ and a′

₀=a₁a₀, wherein a₀ is an initial value of the least significant bit, a′

₀ is an encoded value of the least significant bit, a₁ is an initial value of a second-least significant bit, and a′

₁ is an encoded value of the second-least significant bit;

upon determining that the incremented value results in an overflow of a least significant byte as compared to the stored value, permuting the byte order according to a cyclic byte-wise shift, and storing the incremented value as incremented according to the permuted byte order.

12. An electronic device, comprising:

a memory device comprising rewritable memory; and

at least one processor,

the memory device and the at least one processor being configured to implement a method comprising;

reading in a first value from a set of one or more memory locations of the rewritable memory;

on detection of an instruction to store an incremented value;

permuting the incremented value by, in combination;

applying an encoding, in which a value of a least significant bit changes only on every second increment, to two least significant bits of the incremented value; and

on overflow of a least significant byte as a result of the increment, applying a cyclic byte-wise shift to the incremented value; and

storing the permuted incremented value in the one or more memory locations.

13. The electronic device of claim 12, wherein the rewritable memory comprises EEPROM.

14. The electronic device of claim 12, wherein the first value and the incremented value comprise values in a rolling code algorithm.

15. The electronic device of claim 12, wherein the first value and the incremented value are comprised in a monotonically increasing sequence of multiple-byte binary values.