K524G2GACB-A050 Datasheet, PDF (18/94 Pages) Samsung semiconductor – MCP MEMORY

K524G2GACB-A050
MCP MEMORY
2.0 NAND Flash Technical Notes
2.1 Initial Invalid Block(s)
Initial invalid blocks are defined as blocks that contain one or more initial invalid bits whose reliability is not guaranteed by Samsung. The infor-
mation regarding the initial invalid block(s) is called the initial invalid block information. Devices with initial invalid block(s) have the same qual-
ity level as devices with all valid blocks and have the same AC and DC characteristics. An initial invalid block(s) does not affect the
performance of valid block(s) because it is isolated from the bit line and the common source line by a select transistor. The system design
must be able to mask out the initial invalid block(s) via address mapping. The 1st block, which is placed on 00h block address, is guaranteed
to be a valid block up to 1K program/erase cycles with x8:1bit/ 512Byte, x16:1bit/256Word ECC.
2.2 Identifying Initial Invalid Block(s)
All device locations are erased(FFh) except locations where the initial invalid block(s) information is written prior to shipping. The initial invalid
block(s) status is defined by the 1st byte(1st word) in the spare area. Samsung makes sure that either the 1st or 2nd page of every initial
invalid block has non-FFh data at the column address of 2048(x16:1024). Since the initial invalid block information is also erasable in most
cases, it is impossible to recover the information once it has been erased. Therefore, the system must be able to recognize the initial invalid
block(s) based on the original initial invalid block information and create the initial invalid block table via the following suggested flow chart(Fig-
ure 5). Any intentional erasure of the original initial invalid block information is prohibited.
Start
Set Block Address = 0
Increment Block Address
Create (or update)
Initial
Invalid Block(s) Table
* Check "FFh(x16:FFFFh)" at the
column address 2048(x16:1024)
of the 1st and 2nd page in the block
No
Check
"FFh(x16:FFFFh)"
Yes
No
Last Block ?
Yes
End
Figure 5. Flow chart to create initial invalid block table
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Revision 1.3
November 2009