KM29W040AT Samsung Semiconductor, KM29W040AT Datasheet - Page 9

• Manufacturer Part Number: KM29W040AT
• Manufacturer: Samsung Semiconductor

Specifications of KM29W040AT

• Cell Type: NAND
• Density: 4Mb
• Access Time (max): 15us
• Interface Type: Parallel
• Boot Type: Not Required
• Address Bus: 8b
• Operating Supply Voltage (typ): 3.3/5V
• Operating Temp Range: 0C to 70C
• Package Type: TSOP-II
• Sync/async: Asynchronous
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 5.5V
• Word Size: 8b
• Number Of Words: 512K
• Supply Current: 20mA
• Mounting: Surface Mount
• Pin Count: 40
• Lead Free Status / Rohs Status: Not Compliant

KM29W040AT, KM29W040AIT
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 so called as the invalid block informa-
tion.
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 transistor. The system design must be able to mask out the invalid block(s) via address mapping. The 1st block of the NAND
Flash, however, is fully guaranteed to be a valid block.
All device locations are erased(FFh) except locations where the invalid block information is written prior to shipping.
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.
NAND Flash Technical Notes
Identifying Invalid Block(s)
Increment Block Address
The invalid block information is written to the 1st or the 2nd page of the invalid block(s) with 00h
Invalid Block(s) Table
Create (or update)
Figure 1. Flow chart to create invalid block table.
No
No
Set Block Address = 0
Check "FFH" ?
Last Block ?
9
Start
End
Yes
Yes
*
Check "FFH" on the 1st and 2nd page
FLASH MEMORY
data. Devices with invalid
Since the