Abstract:
A system and method for encoding information arriving from a host in order to store the coded information in flash memory, the method comprising encoding information arriving from a host for storage at a flash memory location including generating a number of redundancy bytes, the encoding proceeding at an encoding rate which is a function of the number of redundancy bytes generated, the encoding including determining an effective error rate, including an anticipated rate of expected reading errors, for the flash memory location; and selecting the encoding rate as a function of the effective error rate such that the number of redundancy bytes is sufficient to overcome the anticipated rate of expected reading errors with a predetermined degree of certainty.
Abstract:
A circuit (10) includes a memory (28, 16, or 26) having error correction, circuitry (30) which initiates a write operation to memory. When error correction is enabled and the write operation to the memory has the width of N bits, the write operation to the memory is performed in one access to the memory, and when error correction is enabled and the write operation to the memory has the width of M bits, where M bits is less than N bits, the write operation to the memory is performed in more than one access to the memory. In one example, the one access to the memory includes a write access to the memory, and the more than one access to the memory includes a read access to the memory and a write access to the memory.
Abstract:
Disclosed are a memory device and a memory data reading method. The memory device may include a multi-bit cell array, a threshold voltage detecting unit configured to detect first threshold voltage intervals including threshold voltages of multi-bit cells of the multi-bit cell array from among a plurality of threshold voltage intervals, a determination unit configured to determine data of a first bit layer based on the detected first threshold voltage intervals, and an error detection unit configured to detect an error bit of the data of the first bit layer. In this instance, the determination unit may determine data of a second bit layer using a second threshold voltage interval having a value of the first bit layer different from the detected error bit and being nearest to a threshold voltage of a multi-bit cell corresponding to the detected error bit.
Abstract:
To provide a Chien search device and a Chien search method capable of performing a Chien search process at a high speed. The Chien search device calculates an error position at the time of correcting an error included in data read from a nonvolatile memory, and includes a first processing unit that performs a search process of an error position in at least one-bit unit to an error-correction area of input data, and a second processing unit that processes at one time plural bits in an non-error-correction-target area of the input data.
Abstract:
A method and system for writing in flash memory, the system operative for, and the method comprising, writing data onto a plurality of logical pages characterized by a plurality of different probabilities of error respectively, the writing including encoding data intended for each of the plurality of physical pages using a redundancy code with a different code rate for each individual physical page, the code rate corresponding to the probability of error in the individual logical page.
Abstract:
Data is read from a nonvolatile memory array using one or more read voltages that are adjusted during memory life. Programming target voltages and read voltages may be adjusted together over memory life to map memory states to an increasingly wide threshold window. Individual memory states are mapped to sub-ranges that are made wider, reducing errors.
Abstract:
Data is read from a nonvolatile memory array using one or more read voltages that are adjusted during memory life. Programming target voltages and read voltages may be adjusted together over memory life to map memory states to an increasingly wide threshold window. Individual memory states are mapped to sub-ranges that are made wider, reducing errors.
Abstract:
A solid state non-volatile memory unit. The memory unit includes a multi-level solid state non-volatile memory array adapted to store data characterized by a first number of digital levels. The memory unit also includes an analog-to-digital converter having an input and an output. The input of the analog-to-digital converter is adapted to receive data from the multi-level solid state non-volatile memory array. The output of the analog-to-digital converter is adapted to output a digital signal characterized by a second number of digital levels greater than the first number of digital levels.
Abstract:
Conventionally it is difficult to judge whether the error, if occurs during read of a nonvolatile memory, is accidental or is the one that may occur frequently due to degradation. Consequently the alternate operation is conducted frequently, and the alternate is used upper, thereby shortening the device life. In a semiconductor storage according to the invention, an alternate operation to be conducted after deducing the cause of the error in the data read out of a nonvolatile memory on the basis of the number of corrections made in the past when the error is corrected or a data refreshing operation is selected. If any error occurs, the data is corrected and rewritten, and thereby accidental error recurrence is prevented. Data judged to have a high error recurrence frequency on the basis of the record of the number of error corrections has a high possibility of containing an error due to degradation, and hence an alternate operation is conducted.