W29N02GVSIAA Datasheet, PDF (72/79 Pages) Winbond – W29N02GV 2G-BIT 3.3V NAND FLASH MEMORY

W29N02GV
12. INVALID BLOCK MANAGEMENT
12.1 Invalid blocks
The W29N02GV may have initial invalid blocks when it ships from factory. Also, additional invalid
blocks may develop during the use of the device. Nvb represents the minimum number of valid blocks
in the total number of available blocks (See Table 12.1). An invalid block is defined as blocks that
contain one or more bad bits. Block 0, block address 00h is guaranteed to be a valid block at the time
of shipment.
Parameter
Valid block number
Symbol
Min
Nvb
2008
Table 12-1 Valid Block Number
Max
2048
Unit
blocks
12.2 Initial invalid blocks
Initial invalid blocks are defined as blocks that contain one or more invalid bits when shipped from
factory.
Although the device contains initial invalid blocks, a valid block of the device is of the same quality
and reliability as all valid blocks in the device with reference to AC and DC specifications. The
W29N02GV has internal circuits to isolate each block from other blocks and therefore, the invalid
blocks will not affect the performance of the entire device.
Before the device is shipped from the factory, it will be erased and invalid blocks are marked. All initial
invalid blocks are marked with non-FFh at the first byte of spare area on the 1^st or 2^nd page. The initial
invalid block information cannot be recovered if inadvertently erased. Therefore, software should be
created to initially check for invalid blocks by reading the marked locations before performing any
program or erase operation, and create a table of initial invalid blocks as following flow chart
Release Date: February 1^st, 2016
72
– Revision B