日本不卡免费一本二本高清 日本不卡三区 日本不卡一区 日本不卡一区二区高清更新 日本不卡一区二区三区 日本不卡一区免费更新一区

Flash???????????Flash?????????????block?????λ?????????????????????洢?豸??????bitλ???С???/д????λ??Flash????????????????飺???????????????????????????block???????????С??128KB/256KB??????????1???????????????????????0xFF???????????????????????????????????????????????????????????????????????Flash Memory?????????Flash????? ??????????档

NAND Flash ?????????????????????????????????????????????????????????Uboot ?? Linux ???? NAND ????????????????????????????????? ???????????Nandflash?????????????????е???????????BBM??????????????????????????? NAND ?洢?????????????????????????????????????????????????????????????????????????????????????????????

?????? 

Flash???????????

Flash??????洢??MOSFET???????и???????(Floating Gate)?????????洢?????????

??Flash??????????????(uv-erasable)??EPROM?????????????Floating Gate?洢??????????????

?????Flash????????? 

??????Flash??浥?????????(electrical charge) ????洢????洢???????????????е??????external gate?????????????????????????洢????г???????????????ɡ?????????????????洢??????????????????????Vth???????????Flash??洢???????????????0????????????洢?豸????????????????0????????1?????????????????????????????????????????0??

NandFlash????

Nand flash???????????????????????????????????д????????????????????ж?????????????????????У??????????ECC?????????????????????????????????Nand Flash????1GB??2GB???????8GB??????????????????????????????????洢??????????????????????е??????????PC???????????洢????????? 

SLC??MLC 

Nand Flash????????洢????????????????Σ???????????浥??У???洢1λ??????????λ???????????SLC??MLC?????????????????????ù???SLC????MLC??? 
Nand Flash????У??и????????Read ID?????ID??????ü????????????????4???????о??????5??????????????Щ????У???????????????????????????Nand Flash????????о???chip????????????chip??????????Plane????????е????С?????С??????????Щ????У????????????????????flash??SLC????MLC?? 

 oob / Redundant Area / Spare Area

????????????????????????????????spare area??/????????redundant area??????Linux???У???????OOB??Out Of Band????????????????????Nand Flash?????????????????д???????????????????????????????????????ж?????????????????????????EDC(Error Detection Code)/ECC??Error Code Correction, ???? Error Checking and Correcting?????????????????????????????????У?????

Oob???д?????????????????????????????????д????????????д??oob??

????oob?????????????????У?

1. ???????????
2. ?洢ECC????
3. ?洢?Щ??????????????????jffs2????????Щ???洢?Щ??????????yaffs2???????????oob?У????????????????????????

Bad Block Management???????

Nand Flash????????????????????????д????????????????????????????????????ù????У???ЩNand Flash??block?????????????????????????????block???????飬??????á?????????????????????Nand Flash????????????????????

Wear-Leveling???????

Nand Flash??block???????????????????

????????Nand Flash??block????????????????????????????????ζ???????block???????д?????????????block???????????????????????????????????????ε??????block????????????????????Щblock???棬?????block??????????????????????????????????????????Nand Flash??

 ECC????У????

Nand Flash????????????????????д?????л????????????????????и???????????????????????????д?ECC???????????????????????Nand Flash??ECC???????????к??????BCH??????????????????????????????????????????????????????????????????????????????

??????????????????ECC????????????????????????????????????????????????????Щ????????????????????????????????????????????ECC??????????????????????????д??????????????????????????????????????????Щ????Nand Flash??????д????????????????

???У?Linux?е????????ECC??????NAND_ECC_SOFT????????????????????

??????????????MLC??Nand Flash????????????????????2GB??4GB??8GB???????BCH????BCH?????????????????????

???????????????????δ?????BCH?????????

BCH???????????????Nand Flash??Controller?У?????????????BCH ECC??飬?????BCH????????????????棬????????????д???????????????????BCH?????????????ó?BCH??????????????BCH????????????????д?????????BCHУ????????д??

????????????β?????Щ?????????????????????????????nand flash??controller?????????????????????????????nand flash?????????????????????????nand flash??controller?????datasheet??????????????????????ɡ?

????????????????????????BCH???????????????????????????????????????Micron????????????????汾??BCH????

λ???

Nand Flash??λ???????????????????Щ???/Ч????????

1. ???Ч???Drifting Effects??

   ???Ч???????Nand Flash??cell????????????????????????????????

2. ?????????????????Program-Disturb Errors??

   ????????????????????????Ч???over-program effect????

   ????????????????????д????????????????????????????λ???????

3. ??????????????????Read-Disturb Errors??

   ??Ч?????????????????????????????????????λ????????????????????仯????Nand Flash????λ????????

???λ??????????Nand Flashλ???????????????????????

1. ?????nand flash???????????洢???????????????????????????????????????????е??λ???????仯????????λ?????????????????????У??λ???????????0???1???????????1???0??????????????????λ???????????λ???????????????????У?????????????
2. ????????????nand flash?е??????洢????У?????????λ?????????????仯???????1????????0?????????0????????1???????????????λ??????仯?????????????????λ?????????????????????????????????????????????????????????????????????????????????????????????????λ??仯??????????????????????????????????????????Erase?????????Block???????????????????????Nand Flash????ù????У??????λ?????????????????????????λ????????

?????????????λ?????????????Nand Flash????????????????????????е?????λ???????????????????????????У???????????ECC???????????????????????

??????????????????????????????????????????????μ??ɡ?

????и???????????ECCУ?鷢???д?????ж????????????λ???????????????

???ж??????????????????????????????????????????????????Nand Flash???????controller?????????????????????????????У?????????

Nand Flash???Щtypical????

1. ??????????200us????Щ??????800us
2. ??????????1.5ms
3. ???????????????????????????20us
4. ???з????Serial access??????????????????25ns?????Щ???Nand Flash??30ns????????50ns
5. ??????????????????????????????multiplex?????
6. Nand Flash????/???????????????????????10??ε???/??????????????????????Nor Flash???????????????????????
7. ????????48?????TSOP1??? ?? 52?????ULGA???

Nand Flash????????Nand Flashо?

????д????????дNand Flash ????????????????????Nand Flash о??????????????????Nand Flashо?????????????????????????????????????????ж?????????Nand Flash???????????????????Nand Flash????????????????????ECCУ??????????????д???????????????????Nand Flash???????

???????????????Nand Flashо???????????????????

????Nand Flash????????????????????С??λ?????????Nand Flash?????????????????????????????????Plane?????????????????????????????????д???????洢?????????????洢????ж????????????????????????????????????????????????buffer???????????datasheet????????????????page register????????????????????棬?????????

???????????Щ?????????????????????????????????????????????????????????Nand Flash??FIFO??д??Nand Flash????????????????????????????д???????洢??????????????????д?????????????У???е????????????????????ε??????????0x10????????????????????????????????е??????????д???????洢????????

???????

????????????????????????????С?2K??Nand Flash??????е???????oob???λ????1?????????С??棬pagesize??512B????256B??Nand Flash???????????6???????????????0xFF???????????顣???????????????????飬???飬???????????????0xFF???

??????????????????????????flash????Щ???????????0xFF??????????????????????????????д?????????ζ???????д???????????????????????????????????????????飬?????????齫?????????????????

uboot???и???????

nand scrub

?????????????е??????????????????????????????????????????????ù????г?????±????

nand erase

????????飬??????????????飬????????????????????????????Щ??????????????Щ???????ù?????????????

Uboot ???????????????????

NAND ??????????????????(BBT)???????????????????е????л??顣?????????????????????????????????????????????????

• ??γ???????????????
• ???????????????α?????????????
• ??α??滵?????????б??????籣???????
• ?? NAND д?????????????????????飬?????????滻???飿

Uboot ?????????????? bootloader????????????????????????????????????????????????????±?????????????????????

??? uboot ???????????????????????Щ??????????????????????????

1. ??????飬?????????д?????????顣??? NAND ?д????????????飬???????鶼????????????????????????飬????????? NAND ?????????????????????ú????? NAND о?????????????????????????о?????????????????? 20 ?? 80?????? NAND ?????????????? N ????飬????????????????С? N*80*128KB??
2. ??? BBT ?????????????ж? BBT ????????У?顣
3. ??е??籣??????????????? BBT ???磬BBT ???????

??????й????????????????????????????????Ч????????????????????????????????????????

???ú??????

?????????????????ú????????д???? NAND ?е?????????滻???顣?????????????????????????????????????????? NAND ???????????

???ú???????

????????ú??????????????????鵽???????????????? BBT ??????趨??????滻??(SBT)????????????????? i ??????????????????? BBT ?м?????????飬??? SBT ?в?????滻?飻???д?? i ?????????????? BBT ?б????????飬????????л?????????飬?????????? j???????????? j д?? SBT ?е?? i ?????????? SBT ??? j ?????д??? i??SBT ?е??????????????????????????????????е????п????????飬???????????????飬?? SBT ?е???λ????? 0x00?????????д??????г???????????? SBT ???λ???? 0x00 ?????????????????????

 BBT/SBT ???????

????? BBT/SBT ????У?????

???????????? BBT ???????????????????????????????????????????б?????????????????????????? BBT??????????????? BBT ????????????? BBT ????????У?顣??? BBT ?????? NAND ?У????????Ч?????????????????? NAND ???????????????????????? ECC У?顣???????????????????? ECC ??????????????? bit?????? 2 ???? bit ???????? BBT ??????????????? ECC У??????洢???У????? NOR Flash????ж? BBT ?????????У??????????????

????????????????? BBT/SBT ?????????????????????????? BBM ?????

BBM ????

typedef struct {
UINT8     acSignature[4];/* BBM ??? */
UINT32    ulBBToffset;/* BBT ??? */
UINT32    ulSBToffset;/* SBT ??? */
UINT16    usBlockNum;/* BBM ?????? block ??? */    
UINT16    usSBTstart;/* SBT ????λ?????? block ??? */
UINT16    usSBtop;/* SBT top block */
UINT16    usSBnum;/* SBT number */
UINT32    ulBBTcrc;/* BBT ???? CRC У???? */
UINT32    ulSBTcrc;/* SBT ???? CRC У???? */
UINT32    ulHeadcrc;/* BBM ???? CRC У???? */
} BBM_HEAD

BBT/SBT ????????

??????? CRC У?????????? BBT ??????????洢???У????????????????????????Ч???

???????籣?????

????????????????? BBT ??????????д BBT ??????磬?? BBT ?????????????????????????????????????????????????????????????????????????д???????????磬???????????????????????????????д?????????????磬???????????????????????

???????????????????????????????????????????????????ü????????????????????????Ч?????????????????????????

???

?????????NandFlash??????????? NAND ?????????????????? uboot ???????????????????????????????????????????? NAND ?????????????????????????????????????к????????á?

ECC????

ECCУ?????????????????????????????????????????????Ρ?ECC??漴??????棬??????????з???????????????????????????????????/??????????ι???????????????????????????????????????

???????

????????????????????乤??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????渽??????????????????????????????????????????

??????????????????????ECC????????????????????????桰???У?飨Parity?????????????С???λ????????????λ??bit??????λ????????????????1??0????????8?????????????????????byte???????????У???????????????8λ?????????λ?洢????????????????洢?????????????仯????????????ó?????????????У?????????????8λ??????????????λ?????????λ?????????д洢???????????8??λ??洢???????��????????λ???????????1??0??????洢????????λ????1??1??1??0??0??1??0??1??????????λ????1+1+1+0+0+1+0+1=5????????????????????У?飬У??λ??????1????????0????????У?飬????????CPU????洢??????????????????8λ?д洢?????????????????????У??λ???????????????????????????????У???????????????????????????????????λ??????????????????????У???????????λ????

??????????????????Parity?????????????????λ??????????????????λ????鵱?8λ?????????????????????λ??????Parity?????????????λ????????????????????λ?16λ??????????2λ?????飬??????λ?32λ?????????4λ??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????漼????????????????ECC?????????????????????????????????????λ?????У??λ??????????????????????????????????????????????????????????????????Parity??????????????λ??8λ???????????5λ??????ECC????????????????λ??????????ECC??????λ????λ??????????????λ?16λ?ECCλ?6λ??32λ?ECCλ?7λ??????λ?64λ?ECCλ?8λ???????????????λ??????????ECCλ??????λ??????????????ECC??????????????????????????????????????????????????????????ж????ECC????????????????????????Parity??????????????λ?????????????????

???

ECC??Error Checking and Correcting????????????????棬??????????????λ??????λ?洢???????????????????????д????棬?????ECC?????????????????????????????????洢???????????????????ECC???????????????????ECC???????????????????????????????????????????????е????λ???????????????????λ??????????????????????????????????????????????????????档??????????????????α??????????????????α???С???д???????????????????????????????????????????????????????????????????????????????????????????????????д??????????????????