The memory is arranged as an array of pages.
A page consists of 256 / 512 Byte data and 8 / 16 Byte spare (out of band) area. Newer chips have 2048 Bytes data and and 64 Bytes spare area sizes.
The spare area is used to store ECC (error correction code), bad block information and filesystem dependend data.
n pages build one block.
The read / write access to data is on a per page basis.
Erase is done on a per block basis.
The commands to read / write / erase the chip is given by writing to the chip with the Command Latch Enable pin high.
Address is given by writing with the Address Latch Enable pin high.
Nand Flash 的 PageSize，Block Number，每个Block有多少个Page，Spare Area的Size，都可以由Chip Id 辨认。
