GD25Q257DFJR datasheet(12/99 Pages) GIGADEVICE

12 / 99 page

3.3V Uniform Sector

Dual and Quad Serial Flash

GD25Q257D

6. ECC Operation

Error Correction Codes (ECC) is a commonly used technique in non-volatile memory to reduce the device Bit Error

Rate (BER) during the device operation life and improve device reliability. To achieve error detection and correction,

redundancy data must be added to store the ECC calculation results for a given length of data. In GD25Q257D, every

aligned 8-Byte data (A[2:0] = 0, 0, 0) stored in the memory array will be checked by the internal ECC engine using SEC-

DED (Single Error Correction

– Double Error Detection) Hsiao Codes algorithm. With 8-Byte ECC data granularity, ECC

calculation latency time can be minimized and highest level of data integrity can be preserved.

The default value of all memory data is FFH (Erased) when the device is shipped from the fa

ctory. A “Page Program

(02H)” or a “Quad Page Program (32H)” command can be used to program the user data into the memory array. When

ECC is enabled (ECC=1 in Status Register), ECC calculation will be performed during the internal programming operation

and the results are stored in the redundancy or spare area of the memory array. It is necessary to program every page in

aligned 8-Byte granularity so that ECC engine can store the correct ECC information. It is also required that every aligned

8-Byte data granularity can only be programmed once to avoid additional ECC calculation in the same granularity resulting

incorrect ECC results. A technique previously known as “Incremental Byte/Bit Programming to the same Byte location”

cannot be used for GD25Q257D when ECC is enabled.

During data read operations, the internal ECC engine will check the ECC results stored in the spare area and apply

necessary error correction or error detection to the main array data being read out. It is necessary to check the ECC Status

Bits (SEC and DED) in the Extended Register after every Read operation to see if the data read out contains any error or

not. A Read operation can start from any Byte address and continue through the entire memory array, so it is not necessary

to align the 8-Byte granularity boundary address to start a Read command.

Additional hardware monitoring of the ECC status can also be used to observe the ECC status in real time during any

data output. When configured, the ECS# (ECC Correction Signal) pin will be pulled low during any aligned 8-Byte data

output if it contains SEC or DED events.

GD25Q257DFJR Datasheet(PDF) 12 Page - GigaDevice Semiconductor (Beijing) Inc.