NM29N16 Datasheet, PDF (26/30 Pages) National Semiconductor (TI) – 16 MBit (2M x 8 Bit) CMOS NAND FLASH E2PROM

Supplementary Device Operation (Continued)
(16) UNUSABLE BLOCK IDENTIFICATION
The NM29N16 may contain unusable blocks To simplify
identification usable or good blocks leave the factory in the
erased state On initial power up (after board assembly)
reading all the bytes in a usable block will result in FFH
being read out Unusable or bad blocks will read out some
data other than FFH These blocks should be mapped out
of the system and not used The valid number of blocks is
as follows
Min Typ Max Unit
Number of good blocks 502 508 512 Block
TL D 11915 – 83
C Checkboard Pattern AAH
C Inverse Checkerboard Pattern 55H
Blank Check Usable blocks will read out ‘FFH’ for all bytes in block
http www national com
FIGURE 26 Identification of Unusable Blocks at Initial Power Up
26
TL D 11915 – 4