The relationship between Nand Flash,nor FLASH,CFI Flash,spi Flash

Preface:
In the embedded development, such as uboot transplant, the kernel transplant all need to have the basic understanding to the flash. Here's a look at the relationship in Flash in the title

one, the memory storage structure of Flash
Flash is divided into two types according to the internal storage structure:NOR FlashAndNAND Flash。

Norflash is easy to use, easy to connect, can run code directly on the chip, excellent stability, high transmission rate, high cost performance in small capacity, which makes it suitable for embedded system as FLASH ROM.
The Norflash,nandflash emphasizes higher performance, lower cost, smaller volume and longer service life. This makes Nandflash very adept at storing pure data or data, and is used in embedded systems to support file systems.

1,nand Flash
There are two types of NAND flash in process manufacturing:MLCAndSLC。 MLC and SLC belong to two different types of NAND flash memory.
SLC full name is Single-level cell, that is, single-layer unit flash, and MLC full name is multi-level cell, that is, multi-layer unit flash.
The difference between them is that SLC each unit, only one data storage, MLC each unit can store two bits of data, MLC data density is one times larger than SLC. There are two types of NAND in page capacity: Large-page NAND flash (e.g. HY27UF082G2B) and small-page NAND flash (e.g., k9f1g08u0a).
These two types differ greatly in page capacity, command sequences, address sequences, in-page access, bad block identifiers, and are subject to different conventions, so pay special attention when porting drivers.

2,nor Flash
In the communication mode nor Flash is divided into two types:CFI FlashAndSPI Flash。

A,CFI Flash
The English name is common Flash interface, which is the public flash interface, is defined by the memory chip industry as a way to obtain the physical parameters of the flash memory chip and structural parameters of the operating procedures and standards. CFI has many rules about flash memory chips, which facilitates the embedded programming of Flash. Many nor FLASH support CFI now, but not all of them are supported.

CFI interface, which is also known as the parallel interface, parallel interface, relative to the SPI of the serial port, in addition, the CFI interface is JEDEC defined, so that some of the CFI interfaces are JEDEC interfaces. Therefore, it can be simply understood as: for nor flash, CFI interface =jedec interface =parallel interface = Parallel interface

B,spi Flash
The Serial Peripheral Interface Serial Peripheral interface is a common clock synchronous serial communication interface.

C,CFI Flash and SPI flash comparison
SPI Flash and CFI Flash media are norflash, but SPI is through the serial interface to achieve data operation, and CFI Flash parallel interface for data operation, SPI capacity is not very large, the market CFI flash bigger can do 128Mbit, and and read-write speed is slow, but the price is cheap, easy to operate. and parallel interface speed, capacity on the market already has 1Gbit capacity, the price is expensive

Second, reference documents
1,http://wenku.baidu.com/link?url=1ajionw_ 7x-vecctxhoyaxq-kt07cwe5bcfl5pnlruxe9xraajrh7gej72i8ule2jbjham76rflwbqhfuijbbumfuubbfhr8-_8vd-9snfo
2,http://www.btdcw.com/btd-b8f73b523c1ec5da51e27004-1.html

The relationship between Nand Flash,nor FLASH,CFI Flash,spi Flash