NAND Flash Memory

NAND flash is a better than hard disk drive storage solution, which in no more than 4GB of low capacity application fared judah is obvious. As people continued pursuit of power consumption more low, lighter weight and performance is better products, NAND is being proved extremely attractive.

introduction

For many consumer audio and video product, NAND flash is a better than hard disk drive storage solution, which in no more than 4GB of low capacity application fared judah is obvious. As people continued pursuit of power consumption more low, lighter weight and performance is better products, NAND is being proved extremely attractive.

NAND flash arrays into a series of 128kB block (which), these block is the youngest of NAND devices can be erased entity. Erase a block is put all the bits (bit) set for "1" (and all bytes (Chinese) is set to FFh). It is necessary to programming, will have erased bits from the "1" into "0". A minimum of programming entity is bytes (Chinese). Some TTL chip can simultaneously execute literacy operation. Although NAND cannot simultaneously execute literacy operation, it can use called "mapping (shadowing)" method, in system-level realize it. This method has been used in a personal computer for years, and is the BIOS from low ROM loading rate on the RAM to rate is higher.

NAND advantages

NAND efficiency is higher, because NAND string no metal contacts. NAND flash unit size smaller than the TTL (4F2:10F2) is attributed to the TTL of each unit needs independent metal contacts. NAND and hard disk drives similar, based on the sector (pp), suitable for storage continuous data, such as pictures, audio or personal computer data. Although through the data mapped to RAM in system-level realize random access, but doing so would require extra RAM storage space. In addition, with hard disk, as NAND devices exist bad sectors, need ECC (ECC) to maintain the integrity of the data.

Storage unit area is smaller, LuoPian the area is smaller. In this case, NAND is able to offer today's low cost consumption market provides storage capacity greater flash memory products. NAND flash for almost all the memory can be erased. NAND the reuse of the interface as all the latest devices and density provides a similar pins output. This pin output makes design engineers without changing circuit board of hardware design, can from smaller density transplanted into greater density on the design.