MT29F8G08FABWP Micron Technology, Inc, MT29F8G08FABWP Datasheet - Page 39

• Manufacturer Part Number: MT29F8G08FABWP
• Manufacturer: Micron Technology, Inc

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2gb_nand_m29b__2.fm - Rev. H 9/05 EN
Micron NAND devices are specified to have a minimum of 2,008 (N
of every 2,048 total available blocks. This means the devices may have blocks that are
invalid when they are shipped. An invalid block is one that contains one or more bad
bits. Additional bad blocks may develop with use. However, the total number of avail-
able blocks will not fall below N
Although NAND memory devices may contain bad blocks, they can be used quite reli-
ably in systems that provide bad-block mapping, replacement, and error correction
algorithms. This type of software environment ensures 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 Flash device.
The first block in each Micron NAND device is guaranteed to be free of defects when
shipped from the factory (up to 1,000 PROGRAM/ERASE cycles). This provides a reliable
location for storing boot code and critical boot information.
Before NAND devices are shipped from Micron, they are erased. The factory identifies
invalid blocks before shipping by programming data other than FFh (x8) or FFFFh (x16)
into the first spare location (column address 2,048 for x8 devices, or 1,024 for x16
devices) of the first 2 pages of each bad block.
System software should check the first spare address on the first 2 pages of each block
prior to performing any erase or programming operations on the Flash device. A bad
block table can then be created, allowing system software to map around these areas.
Factory testing is performed under worst-case conditions. Because blocks marked “bad”
may be marginal, it may not be possible to recover this information if the block is erased.
Over time, some memory locations may fail to program or erase properly. In order to
ensure that data is stored properly over the life of the Flash device, certain precautions
must be taken, such as:
• Always check status after a WRITE, ERASE, or DATA MOVE operation.
• Use some type of error detection and correction algorithm to recover from single-bit
• Use a bad-block replacement algorithm.
errors.
2, 4, and 8Gb x8/x16 Multiplexed NAND Flash Memory
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during the endurance life of the product.
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2004 Micron Technology, Inc. All rights reserved.
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) valid blocks out