GD5F1GQ4REFIS datasheet(44/60 Pages) GIGADEVICE

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SPI(x1/x2/x4) NAND Flash

Table13-5. Driver Register Bits Descriptions

DS_S1

DS_S0

Driver Strength

50%

25%

75%

100%

13.4 Assistant Bad Block Management

As a NAND Flash, the device may have blocks that are invalid when shipped from the factory, and a minimum number of

valid blocks (NVB) of the total available blocks are specified. An invalid block is one that contains at least one page that has

more bad bits than can be corrected by the minimum required ECC. Additional bad blocks may develop with use. However,

the total number of available blocks will not fall below NVB during the endurance life of the product.

Although NAND Flash memory devices may contain bad blocks, they can be used reliably in systems that provide

bad-block management and error-correction algorithms, which ensure data integrity. Internal circuitry isolates each block

from other blocks, so the presence of a bad block does not affect the operation of the rest of the NAND Flash array.

NAND Flash devices are shipped from the factory erased. The factory identifies invalid blocks before shipping by

programming the Bad Block Mark (00h) to the first spare area location in each bad block. This method is compliant with

ONFI Factory Defect Mapping requirements. See the following table for the bad-block mark.

System software should initially check the first spare area location for non-FFH data on the first page of each block prior to

performing any program or erase operations on the NAND Flash device. A bad-block table can then be created, enabling

system software to map around these areas. Factory testing is performed under worst-case conditions. Because invalid

blocks may be marginal, it may not be possible to recover the bad-block marking if the block is erased.

To simplify the system requirement and guard the data integration, GigaDevice SPI NAND provides assistant

Management options as below.

Table13-6. Bad Block Mark information

Description

Density

Requirement

Minimum number of valid blocks (NVB)

1004

Total available blocks per die

1024

First spare area location

Byte 2048

Bad-block mark

00h(use non FFH to check)

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