Method for page- and block based scrambling in non-volatile memory
A method and system for programming and reading data with reduced read errors in a memory device. In one approach, date to be written to the memory device is scrambled using a first pseudo random number which is generated based on a number of a page of the memory device to which the data is to be written and a second pseudo random number which is generated based on a number of a block of the memory device to which the data is to be written. This avoids bit line-to-bit line and block-to-block redundancies which can result in read errors. The data may also be scrambled based on a number of a section within a page.
1. A method of writing data into a page of a flash memory device, where the pages of the flash memory device are grouped into blocks that are each erasable as a single unit, the method comprising:
receiving data to be stored in the page;
generating a first number that depends on a block number of the block containing the page;
generating a second number that depends on a number of the page within the block containing the page;
scrambling the data to generate scrambled data, where the scrambling depends on the first number and the second number; and
writing the scrambled data into the page.
2. The method of claim 1 , wherein the scrambled data is an XOR of the received data, the first number and the second number.
3. The method of claim 1 , wherein the first number depends on the block number of the block containing the page, but not on the page number within the block.
4. The method of claim 1 , wherein the second number depends nonlinearly on the number of the page within the block containing the page.
5. The method of claim 1 , wherein the page comprises multiple sections, and the scrambling depends on a number of a section within the page.
6. The method of claim 5 , wherein the dependency on the number of the section within the page is nonlinear.
7. The method of claim 1 , wherein the first and second numbers are pseudo random numbers.