
K9F1608W0A-TCB0, K9F1608W0A-TIB0
FLASH MEMORY
9
Identifying Invalid Block(s)
All device locations are erased(FFh) except locations where the invalid block information is written prior to shipping.
Since the
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 invalid block(s) based on the original invalid block
information and create the invalid block table via the following suggested flow chart(Figure 1). Any intentional era-
sure of the original invalid block information is prohibited.
Invalid Block(s)
Invalid blocks are defined as blocks that contain one or more invalid bits whose reliability is not guaranteed by Samsung. Typically,
an invalid block will contain a single bad bit. The information regarding the invalid block(s) is called as the invalid block information.
The invalid block information is written to the 1st or the 2nd page of the invalid block(s) with 00h data.
Devices with invalid block(s)
have the same quality level or as devices with all valid blocks and have the same AC and DC characteristics. An 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 tran-
sistor. The system design must be able to mask out the invalid block(s) via address mapping. The 1st block of the NAND Flash, how-
ever, is fully guaranteed to be a valid block.
NAND Flash Technical Notes
*
Check "FFH" on the 1st and 2nd page
Figure 1. Flow chart to create invalid block table.
Start
Set Block Address = 0
Check "FFH"
Increment Block Address
Last Block
End
No
Yes
Yes
Create (or update)
Invalid Block(s) Table
No