Error management processes for flash EEPROM memory arrays
AssigneeIntel Corporation
InventorsMark Christopherson, Steven Wells, Greg Atwood, Mark Bauer, Albert Fazio, Robert Hasbun
Life of this patent
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Abstract
A method of utilizing circuitry including error detecting and correcting circuitry to detect and correct errors which can occur in data stored in multi-bit per cell format in a flash EEPROM memory array before those errors can affect the accuracy of data provided by a flash EEPROM memory array.
Claims18
A method of managing data in a flash electrically-erasable programmable read only memory (EEPROM) array including separately erasable blocks of memory devices arranged to stored data in sectors, the method comprising the steps of:
- detecting errors present in a sector of an array being read,
- terminating the detection process if no errors are detected,
- correcting the errors if less than a first number of errors are detected,
- retrying the detection of errors in the sector of an array if greater than the first number of errors is detected,
- correcting the errors after the retrying if less than a second number of errors greater than the first number of errors are detected,
- marking the block of the array questionable if more than the second number of errors but less than a third number of errors is detected, which is the greatest the error detection process is able to correct, is detected;
- and then
- correcting the errors which are detected,
- rewriting the sector of data to a new position,
- checking whether the block has been marked questionable previously,
- if the block has been marked questionable previously, removing the block from service;
- and
- if more than the third number of errors is detected, removing the block from service.
A method of managing data in a flash electrically-erasable programmable read only memory (EEPROM) array including separately erasable blocks of memory devices arranged to stored data in sectors, the method comprising the steps of:
- detecting errors present in a sector of an array being read,
- determining the number of errors and the position of each of the errors detected,
- terminating the detection process if no errors are detected,
- correcting the errors if less than a first number of errors are detected,
- marking the block of the array questionable if more than the first number of errors but less than a second number of errors is detected is detected;
- and then
- correcting the errors which are detected,
- rewriting the sector of data to a new position,
- checking whether the block with errors has been marked questionable previously;
- if the block has been marked questionable previously, removing the block from service;
- and
- if more than the second number of errors is detected, removing the block from service.
Dependencies are inferred from the claim text.