K5P2880YCM Datasheet, PDF (11/29 Pages) Samsung semiconductor – Multi-Chip Package MEMORY 128M Bit 16Mx8 Nand Flash Memory / 8M Bit 1Mx8/512Kx16 Full CMOS SRAM

K5P2880YCM - T085
NAND Flash Technical Notes
Invalid Block(s)
Invalid blocks are defined as blocks that contain one or more invalid bits whose reliability is not guaranteed by Samsung. The infor-
mation regarding the invalid block(s) is so called as the invalid block information. 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 perfor-
mance 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.
Identifying Invalid Block(s)
All device locations are erased(FFh) except locations where the invalid block(s) information is written prior to shipping. The invalid
block(s) status is defined by the 6th byte in the spare area. Samsung makes sure that either the 1st or 2nd page of every invalid
block has non-FFh data at the column address of 517. Since the invalid block information is also erasable in most cases, it is impos-
sible 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 10). Any
intentional erasure of the original invalid block information is prohibited.
Start
Set Block Address = 0
Increment Block Address
Create (or update)
No
Invalid Block(s) Table
* _{Check "FFh" ?}
Check "FFh" at the column address 517
of the 1st and 2nd page in the block
Yes
No
Last Block ?
Yes
End
Figure 10. Flow chart to create invalid block table
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Revision 0.0
June. 2001