WinCE -BSP NAND flash 坏块处理

(三星K9GAG08U0D)

1. Indentifying 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 in the spare area. Samsung makes sure that the last page of every initial invalid block has non-FFh data at the column address of 4096. The initial invalid block information is also erasable in most cases,and it is impossible to recover the information once it has been erased. Therefore,the system must be able to recognize the initial invalid blocks based on the initial invalid block information and create the initial invalid block table via the following suggested flow char. Any intentional erasure of the initial invalid block information is prohibited.

2. Error in write or read operation

Within it's life time,additional invalid blocks may develop with NAND flash memory. Refer to the qualification report for the actual data. Block replacement should be done upon erase or program error.

3. Block Replacement

(1). when an error happens in the nth page of the block 'A' during erase or program operation.

(2). copy data in the 1st ~ (n-1)th page to the same location of another free block. (Block 'B')

(3). then,copy the nth page data of the block 'A' in the buffer memory to the nth page of the block 'B'

(4). do not erase or program block 'A' by creating an "invalid block" table or other appropriate scheme.