MT29F1G08ABBHC-ET Micron, MT29F1G08ABBHC-ET Datasheet - Page 50

• Manufacturer Part Number: MT29F1G08ABBHC-ET
• Description: NAND Flash Memory; Density: 1Gb; Organization: 128Mbx8; Bits/Cell: SLC; I/O: Common; Supply Voltage: 1.8V; Operating Temperature Range: -40° to +85°C; Package: 63-VFBGA
• Manufacturer: Micron

Error Management
PDF: 09005aef81dc05df / Source: 09005aef821d5f08
1gb_nand_m48a__2.fm - Rev. E 1/08 EN
Micron MT29F1Gxx NAND Flash devices are specified to have a minimum of 1,004 valid
blocks (N
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
available blocks will not fall below N
Although NAND Flash memory devices may contain bad blocks, they can be used quite
reliably 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 NAND Flash device.
The first block (physical block address 00h) for each CE# in Micron NAND Flash devices
is guaranteed to be free of defects (up to 1,000 PROGRAM/ERASE cycles) when shipped
from the factory. This provides a reliable location for storing boot code and critical boot
information.
Before NAND Flash devices are shipped from Micron, they are erased. The factory iden-
tifies 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 or second page of each bad block.
System software should check the first spare address on the first and second page of
each block prior to performing any erase or formatting 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 blocks
marked “bad” may be marginal, it may not be possible to recover this information if the
block is erased.
If the NAND Flash device is erased before these operations are performed, system soft-
ware must determine which blocks are bad by writing and verifying valid information in
each memory location in the device. After writing and verifying all locations, the device
must be fully erased and checked to verify that each block has erased properly.
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 NAND Flash device, certain pre-
cautions must be taken, including:
• Always check status after a WRITE or ERASE operation.
• Under typical use conditions, utilize a minimum of 1-bit ECC for each 528 bytes of
• Use a bad-block replacement algorithm.
data.
VB
) out of 1,024 total available blocks. This means the devices may have blocks
50
VB
.
Micron Technology, Inc., reserves the right to change products or specifications without notice.
1Gb: x8, x16 NAND Flash Memory
©2006 Micron Technology, Inc. All rights reserved.
Error Management