Choice leading your NAND to implement
NAND glimmer because of every a little and high density advantage low expenses employ, become, go magnanimity those of memory prevailing to choose, cross even without glare in consumer. Moreover, NAND has a trumpet, it has firm advantages and fewer ability exceeds HDDs.
Because the demand for NAND increased glimmers, the density rises sharply, designers faced the type has glimmered from many kinds of NAND chosen challenges that came out, density, seller, road picture and implementing.
Standard for selection
Implementation that it is NAND controller that the first is suitable for using NAND to glimmer with the standard of the most important up-market selected works. All NAND glimmer the apparatus needs to lie in to guarantee the software of a outside controller of the reliable data and maintenance of hardware at the top of the head, the apparatus has glimmered and improve performance to enable the life-span of maximizing NAND. 3 serious pieces of management functions of main NAND controller, wear and enable into the level and code (ECC) Wrong correction .
NAND glimmers and uses the memory of shop called group of one. Most NAND glimmer apparatus born with some serious block build, lay, test foundation that guide during production together. The one will be called in the apparatus seller’s explanation badly.
Good one may reduce and must be passed the software (the management of bad block) during lifespan of NAND Follow . In addition, identical special block cause block those right perhaps” Wear-out ” And become bad one of one. Make NAND life maximize and total amount that limit exhaust block, all block should read and write to average to wear competence of making into in a series of development that ask.
Mistake perhaps because one special activity or operate, appear of cabin, and ECC must be realized finding and correcting these mistakes in the software or hardware. Can usually confirm ECC in the quantity industry of the location which every 528 bytes department correct as the code. In a system, this NAND may choose to be combined in 3 kinds of different implementation with NAND to control personnel, as figure shows.
Until 3 choice of solution chosen to come out together from NAND, one designer must choose NAND glimmer apparatus between two too: Cabin (SLC) of the single level NAND and multi-layer cabin (MLC) NAND. Every one offers its own advantage.
SLC NAND offers longer lifespan and dependability of each one, so less ECC needed and offering performance superiorly. MLC NAND expects much the step of management of harmful block, wears and enables into level and ECC. However, MLC NAND is probably every 1/3 of the price of SLC NAND.
Choose
Use, have 1 one all NAND interface and controller of choice that prefer usually in designer, where is a microprocessor chosen. Most contemporary microprocessors, if they really have any support to NAND, usually support SLC NAND only in lower density. Those process technologies restrain those total amount stored from extremely having SLC or MLC NAND about one, because probably 1 Gbyte that this density stores in each concave model’s mould at present. So for high density to support NAND, first control person must be able to support many NANDs. This is usually used to do the course and much slice alternately to enable to become possible.
At present, the level of ECC needed for MLC NAND by 4, but is moving to 8 and 12 rapidly. The total amount of higher ECC needs the hardware in NAND controls personnel. However, compare with MLC NAND that is formed progressively rapidly, the microprocessor evolves slower paces and goes on.
” NAND controlled ” Close (choose 2) It is useful to use a lot of different embedding and portable type stored. All portable SD/MMC card use the implementation, imbed the market NANDs that control, and there are several choices. When the microprocessor only needs to support interface of a SD/MMC type to increase the systematic support to SLC or MLC NAND, this kind of method has its advantage.
The controller is piled up and handled in all harmful blocks by NAND and managed, wear and enable into ECC of level and NAND. NAND controlled implements in the course of employing embeddedly and in probably 4 Gbyte density is being seen at present that 8 Gbyte portable card is inherent.
The unfavorable conditions with this method are that each NAND supplier supports different interface on the kind of NAND of their control, require the intact software to overhaul from a NAND seller for another change.
Choose 3 in types of choosing NAND and give the designer most flexibility in the course of selecting from different sellers. Nearly all NAND control personnel and support different types, seller and density of NAND. Because NAND controller reaches the processor to use the same interface forever, the designer chooses without needing to change different types and supplier of NAND of any software freely.
