KBE00S009M Datasheet, PDF (16/86 Pages) Samsung semiconductor – 1Gb NAND x 2 + 256Mb Mobile SDRAM x 2

KBE00S009M-D411
MCP MEMORY
NAND Flash Technical Notes (Continued)
Error in write or read operation
Within its life time, the additional invalid blocks may develop with NAND Flash memory. Refer to the qualification report for the actual
data.The following possible failure modes should be considered to implement a highly reliable system. In the case of status read
failure after erase or program, block replacement should be done. Because program status fail during a page program does not
affect the data of the other pages in the same block, block replacement can be executed with a page-sized buffer by finding an
erased empty block and reprogramming the current target data and copying the rest of the replaced block. In case of Read, ECC
must be employed. To improve the efficiency of memory space, it is recommended that the read or verification failure due to single bit
error be reclaimed by ECC without any block replacement. The said additional block failure rate does not include those reclaimed
blocks.
Write
Read
Failure Mode
Erase Failure
Program Failure
Single Bit Failure
Detection and Countermeasure sequence
Status Read after Erase --> Block Replacement
Status Read after Program --> Block Replacement
Verify ECC -> ECC Correction
ECC
: Error Correcting Code --> Hamming Code etc.
Example) 1bit correction & 2bits detection
Program Flow Chart
Start
Write 80h
Write Address
Write Data
Write 10h
Read Status Register
I/O 6 = 1 ?
No
or R/B = 1 ?
*
No
Program Error
Yes
I/O 0 = 0 ?
Yes
Program Completed
* : If program operation results in an error, map out
the block including the page in error and copy the
target data to another block.
Revision 1.0
May 2005
16