Counter in a flash memory

Patent metadata

Field	Value
Publication number	US-2017337104-A1
Application number	US-201615378569-A
Country	US
Kind code	A1
Filing date	Dec 14, 2016
Priority date	May 20, 2016
Publication date	Nov 23, 2017
Grant date	—

Abstract

A method of storing at least one counter into a flash memory, wherein each page of the memory assigned to the storage of the counter(s) includes: header data including a first word intended to contain a number of the page, one word per counter to store a first value thereof, and a second word intended to contain an error control code calculated by taking into account the first values; frames all having a same number of words, each frame being intended to contain a value independent from the frame data, and at least one occurrence of an identifier of a counter, each written frame representing an increment or decrement of the value of the concerned counter with respect to its first value.

First claim

What is claimed is:

1 . A method, comprising:
calculating an initial error control code taking into account a first value of a counter; and storing the counter into a selected page of a flash memory having a plurality of pages, wherein the storing includes:
writing header data into the selected page, the header data including a first word containing a number of the page, a second word containing a first value of the counter, and a third word containing the initial error control code;
writing counter information into frames of the selected page, the frames all having a same number of words, wherein, for each frame, writing the counter information includes writing into the frame a counter identifier that identifies the counter, the counter identifier representing an increment or decrement of the concerned counter; and
writing into each frame in which the counter identifier, a value independent from the identifier of the counter.

2 . The method of claim 1 , wherein writing the counter information includes updating a value of the counter by writing the counter information into a new frame of the selected page.

3 . The method of claim 1 , wherein the counter information is written sequentially into the frames of the selected page.

4 . The method of claim 1 , wherein writing the counter information includes, for each frame, calculating a frame error control code word by taking into account the counter identifier in the frame.

5 . The method of claim 1 , wherein said value independent from the counter identifier is the same for all the frames in the page.

6 . The method of claim 1 , wherein said header data are written before a first frame is written into the page.

7 . The method of claim 1 , further comprising calculating a current value of the counter by incrementing or decrementing the counter a number of times equal to how many frames in the page include the counter identifier of the counter.

8 . The method of claim 1 , wherein writing the counter information includes, each frame, writing an increment value or a decrement value of the counter into the frame.

9 . The method of claim 8 , further comprising calculating a current value of the counter by incrementing or decrementing the counter by the increment or decrement value a number of times equal to how many frames in the page include the counter identifier of the counter.

10 . The method of claim 1 , wherein writing header data into the selected page goes includes calculating the first value of the counter based on a previous counter value in a previous page.

11 . A flash memory control circuit that, in operation, performs a method comprising:
calculating an initial error control code taking into account a first value of a counter; and storing the counter into a selected page of a flash memory having a plurality of pages, wherein the storing includes:
writing header data into the selected page, the header data including a first word containing a number of the page, a second word containing a first value of the counter, and a third word containing the initial error control code;
writing counter information into frames of the selected page, the frames all having a same number of words, wherein, for each frame, writing the counter information includes writing into the frame a counter identifier that identifies the counter, the counter identifier representing an increment or decrement of the concerned counter; and
writing into each frame in which the counter identifier, a value independent from the identifier of the counter.

12 . The flash memory control circuit of claim 11 , wherein writing the counter information includes updating a value of the counter by writing the counter information into a new frame of the selected page.

13 . The flash memory control circuit of claim 11 , wherein the method includes calculating a current value of the counter by incrementing or decrementing the counter a number of times equal to how many frames in the page include the counter identifier of the counter.

14 . The flash memory control circuit of claim 11 , wherein writing the counter information includes, each frame, writing an increment value or a decrement value of the counter into the frame, and the method includes calculating a current value of the counter by incrementing or decrementing the counter by the increment or decrement value a number of times equal to how many frames in the page include the counter identifier of the counter.

15 . The flash memory control circuit of claim 11 , wherein writing header data into the selected page goes includes calculating the first value of the counter based on a previous counter value in a previous page.

16 . An electronic circuit comprising:
a flash memory; and a flash memory control circuit that, in operation, performs a method that includes:
calculating an initial error control code taking into account a first value of a counter; and
storing the counter into a selected page of a flash memory having a plurality of pages, wherein the storing includes:
writing header data into the selected page, the header data including a first word containing a number of the page, a second word containing a first value of the counter, and a third word containing the initial error control code;
writing counter information into frames of the selected page, the frames all having a same number of words, wherein, for each frame, writing the counter information includes writing into the frame a counter identifier that identifies the counter, the counter identifier representing an increment or decrement of the concerned counter; and
writing into each frame in which the counter identifier, a value independent from the identifier of the counter.

17 . The electronic circuit of claim 16 , wherein writing the counter information includes updating a value of the counter by writing the counter information into a new frame of the selected page.

18 . The electronic circuit of claim 16 , wherein the method includes calculating a current value of the counter by incrementing or decrementing the counter a number of times equal to how many frames in the page include the counter identifier of the counter.

19 . The electronic circuit of claim 16 , wherein writing the counter information includes, each frame, writing an increment value or a decrement value of the counter into the frame, and the method includes calculating a current value of the counter by incrementing or decrementing the counter by the increment or decrement value a number of times equal to how many frames in the page include the counter identifier of the counter.

20 . The electronic circuit of claim 16 , wherein writing header data into the selected page goes includes calculating the first value of the counter based on a previous counter value in a previous page.

Assignees

• Proton World Int Nv

Inventors

• Dawirs Michel
• Docquier Guillaume

Classifications

• G06F2212/1032

  Reliability improvement, data loss prevention, degraded operation etc · CPC title

• H03K23/56

  Reversible counters (H03K23/52 {and H03K23/548} take precedence) · CPC title

• G06F2212/7209

  Validity control, e.g. using flags, time stamps or sequence numbers · CPC title

• G06F12/0246 Primary

  in block erasable memory, e.g. flash memory · CPC title

• G06F2212/7207

  management of metadata or control data · CPC title