Currently there are two main Flash and NOR Flash NADN Flash. NOR Flash read and read our common SDRAM are the same, the user can run the code is loaded directly inside the NOR FLASH, SRAM can be reduced so that the capacity of such cost savings.
NAND Flash memory, random access not taken technology, it is read in the form of one of the first reading is performed, usually a 512 byte read, using this technology Flash relatively inexpensive. Users can not directly run the code on NAND Flash, so a lot of use of NAND Flash development board in addition to the use of NAND Flah, it also made a small piece of NOR Flash to run the boot code. General small-capacity used NOR Flash, because of its fast read speed, usually used to store important information such as operating system, and with large-capacity NAND FLASH, NAND FLASH most common application is an embedded system using the DOC (Disk On Chip) and we usually use "flash", you can erase online. FLASH currently on the market mainly from Intel, AMD, Fujitsu and Toshiba, while NAND Flash production of major manufacturers are Samsung and Toshiba.
NOR and NAND market is now two main nonvolatile flash memory technology. First developed in 1988, Intel NOR flash technology, completely changed the original EPROM and EEPROM domination. Then, in 1989, Toshiba issued a NAND flash architecture, emphasizing lower cost per bit, higher performance, and the same as the disk can be easily upgraded through the interface. But after more than a decade, there are still a considerable number of hardware engineers tell NOR and NAND flash memory. As "flash memory" and often with "the NOR memory" are used interchangeably. Many in the industry also confused NAND flash technology with respect to Youyuezhichu NOR technology, because in most cases the flash memory used to store only a small amount of code, then NOR flash more suitable for some. While NAND is a high-density data storage ideal solution.
NOR market is now the main non-volatile flash memory technology. NOR generally used to store a small amount of code; NOR mainly used in the code storage medium. NOR features is simple application, no special interface circuitry, high transmission efficiency, it belongs to the implementation of (XIP, eXecute In Place) chip, so that the application can run in the flash memory (NOR type) Flash directly, then the code does not have to read the system RAM. Having a highly cost-effective at 1 ~ 4MB of small capacity, but low write and erase speeds greatly affect its performance. NOR flash with SRAM interface, sufficient to address the address pins, can easily access the inside of each byte. NOR flash accounted for a capacity of 1 ~ 16MB flash memory market most.
NAND structure can provide high cell density, high storage density can be achieved, and the speed of writing and erasing quickly. Application of NAND flash difficulties that require special management and system interface.