k9f4g08u0m-y Samsung Semiconductor, Inc., k9f4g08u0m-y Datasheet - Page 13

• Manufacturer Part Number: k9f4g08u0m-y
• Description: 512m X 8 Bits / 1g X 8 Bits Nand Flash Memory
• Manufacturer: Samsung Semiconductor, Inc.

K9K8G08U1M
K9F4G08U0M
NAND Flash Technical Notes
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 information regarding the initial invalid block(s) is called the initial invalid block information. Devices with initial invalid block(s)
have the same quality 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 tran-
sistor. 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, does not require Error Correction up to 1K program/erase cycles.
All device locations are erased(FFh) except locations where the initial invalid block(s) information is written prior to shipping. The ini-
tial invalid block(s) status is defined by the 1st byte 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. 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(Figure 3). Any intentional erasure of the original initial invalid block information is prohibited.
Identifying Initial Invalid Block(s)
Increment Block Address
Invalid Block(s) Table
Create (or update)
Initial
Figure 3. Flow chart to create initial invalid block table
No
No
Set Block Address = 0
Last Block ?
Check "FFh"
13
Start
End
Yes
Yes
*
Check "FFh" at the column address 2048
of the 1st and 2nd page in the block
FLASH MEMORY
Advance