NandFlash數(shù)據(jù)存儲(chǔ)規(guī)則與數(shù)據(jù)讀寫方法

NandFlashNANDFlashNandFlash的芯片為例作了具體的解釋。NANDFlashbitmemorycell，一般來(lái)說(shuō)，cell816bit，(NandFlashNandFlashK9F1208,K9F1208U0M)，528Byte32形成一個(gè)BlockSizeof(block)=16kByte。1block=16kbyte，512Mbit=64Mbyte，Numberof(block)=40961block=32,1=528byte=512byte(MainArea)+16byte(SpareArea)Nandflash式可以形成所謂的三類地址：--BlockAddress--Address--ColumnAddressNANDFlash來(lái)講，地址和命令只能在I/O[7:0]8位。512byte9bit528byteNAND512byte1sthalf2ndhalf,各自的訪問(wèn)由地址指針命令來(lái)選擇，A[7:0]就是所謂的column對(duì)地址。BlockA14以上的bit來(lái)表示，例如512Mb的NAND，共12bitA[25:14]，1Gbit的528byte/NANDFlashblockaddressA[26:24addressblcokaddress|addressinblockNANDFlash的地址表示為：BlockAddress|Addressinblock|halfpointer|ColumnAddress地址傳送挨次是ColumnAddress,Address,BlockAddress。由于地址只能在I/O[7:0]512Mbitx8NANDflash，0~0x3FF_FFFF，只要是這個(gè)范圍內(nèi)的數(shù)值表示的地址都是有效的。NAND_ADDR為例：1columnaddress，NAND_ADDR[7:0]，不需移位即可傳遞到pointerbit8是由操作指令打算的，即指令打算halfbit8don”tcare的。9NAND_ADDR[16:9]I/O[7:0]上3NAND_ADDR[24:17I/O上I/O4步才4-stepaddressing。NANDFlash256Mbit以下，那么，blockadress最高位只到3x16NANDflash器件略微進(jìn)展一mainarea256word512byte。bit8完全不用管，地址傳遞照舊和x8器NANDx8nandflashblock，每個(gè)block。一般而言，block、隨著芯片的不同而不同，典型的安排是這樣的：1block=321=512bytes(datafield)+16bytes(oob)flashblock512bytes1sthalf和2sdhalf，half256K9F1208U0B4096個(gè)Blocks，flash4096*(32*528)=69206016Bytes=66MB最終16Bytes*(32*512)=67108864Bytes=64MB，1528Bytes528〔1Byte00Byte11Byte，81Byte1bit〕。這528BytesDataFieldSpareField，其中SpareField占528Bytes里的16Bytes,這16Bytes是用于在讀寫操作的時(shí)候存放校驗(yàn)16Bytes512BytesDataField，528Bytes，但512BytesNandFlash讀命令有兩個(gè)，分別是Read1,Read2Read1DataFieldRead2SpareFieldNandFlash，也就是說(shuō)當(dāng)我們給定了讀取的起始位置后，讀操作將從Byte〔SpareFieldNandFlashNandFlashColumnAddressAddress.進(jìn)展尋址。ColumnAddressBytePaageAddress：頁(yè)地址。由于頁(yè)地址總是以512Bytes90FlashRead1src_addrColumnAddressAddress：column_addr=src_addr%512;//columnaddress_address=(src_addr>>9);//addressNandFlashA0~A7rA8A8你將了解到這是什么緣由)Read1命令的操作分為4Cycle，發(fā)送完讀命令00h或01h〔00h與01h的區(qū)分請(qǐng)見(jiàn)下文描述4Cycle1st.Cycle,3rd.Cycle4th.CycleAddress〔每次向17Address3Read100h01h。這里消滅了兩K9F1208U0BDataField2half如上文我所提及的，Read11st.CycleColumnAddress，假設(shè)我0，0Byte是127，狀況也與前面一樣，但不知道你覺(jué)察沒(méi)有，用于傳遞ColumnAddress8〔I/O0~I/O7，對(duì)應(yīng)A0~A7，這也是A8的地址位中〕，也就是說(shuō)我們能夠指定的ColumnAddress范圍為0~255，但不命令從第256個(gè)字節(jié)處開頭讀取此頁(yè)，那將會(huì)發(fā)生什么情景？我必需把ColumnAddressColumnAddress。DataField〔ColumnAddress〕0~25500h256byte頁(yè)，那么我將這樣發(fā)送命令串：column_addr=256;從2ndNF_CMD=0x01; half開頭讀取NF_ADDR=column_addr&0xff;1stCycleNF_ADDR=_address&0xff;2nd.CycleNF_ADDR=(_address>>8)&0xff;3rd.CycleNF_ADDR=(_address>>16)&0xff;4th.Cycle其中NF_CMD和NF_ADDR分別是NandFlash的命令存放器和地址存放器的地址解引用，我一般這樣定義它們：#definerNFCMD(*(volatileunsignedchar*)0x4e000004)//NADDFlashcommand#definerNFADDR(*(volatileunsignedchar*)0x4e000008)//NANDFlashaddressA801h是00h這兩個(gè)命令來(lái)置高位或是置低位〕，這樣我們傳遞column_addr的值256NF_CMD=0x011所以我們傳到地址存放器里的值變成了：A0A1A2A3A4A5A6A7A8100000001256byte〔2ndhalf0byte〕開頭讀取數(shù)據(jù)。nand_flash.c3voidnf_reset(void);voidnf_init(void);voidnf_read(unsignedintsrc_addr,unsignedchar*desc_addr,intsize);nf_init調(diào)用。nf_initnand_flashnandflash，nf_init必需被調(diào)用。nf_read(unsignedintsrc_addr,unsignedchar*desc_addr,intsize);src_addrnandflash，desc_addr，size讀取文件的長(zhǎng)度。nf_resetnf_readNF_nFCE_L;NF_nFCE_H;NandFlashNF_nFCE_L必定被調(diào)用，F(xiàn)lash〔片選/取消片選〕nf_reset中的：rNFCONF=(1<<15)|(1<<14)|(1<<13)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);,rNFCONFNandFlashs3c2410NandFlash中的第5000字節(jié)處開頭讀取10240x30000000read函數(shù)：nf_read(5000,0x30000000,1024);5000src_addr.：依據(jù)column_addr=src_addr%512;_address=(src_addr>>9);我們可得出：column_addr=5000%512=392_address=(5000>>9)=99392nf_readcolumn_addr=5000%512;>_address=(5000>>9);NF_ADDR=column_addr&0xff;1stCycleNF_ADDR=_address&0xff;2nd.CycleNF_ADDR=(_address>>8)&0xff;3rd.CycleNF_ADDR=(_address>>16)&0xff;4th.CyclerNFDATA(NandFlash我用下面的代碼進(jìn)展數(shù)據(jù)的讀取.：for(i=column_addr;i<512;i++){*buf++=NF_RDDATA;}0Column(0Byte).NandFlash下面是源代碼：/*本代碼只屬于溝通學(xué)習(xí)，不得用于商業(yè)開發(fā)*/#include“s3c2410.h“#include“nand_flash.h“staticunsignedcharseBuf[16]={0xff};//-------------------------------------------------------------------unsignedshortnf_checkId(void){inti;unsignedshortid;NF_nFCE_L;//chipenableNF_CMD(0x90);//ReadIDNF_ADDR(0x0);for(i=0;i<10;i++);//waittWB(100ns)id=NF_RDDATA<<8;//Makercode(K9S1208V:0xec)id|=NF_RDDATA;//Devidecode(K9S1208V:0x76)NF_nFCE_H;//chipenablereturnid;}//-------------------------------------------------------------------staticvoidnf_reset(void){inti;NF_nFCE_L;//chipenableNF_CMD(0xFF);//resetcommandfor(i=0;i<10;i++);//tWB=100ns.NF_WAITRB;//wait200~500us;NF_nFCE_H;//chipdisable}//-------------------------------------------------------------------voidnf_init(void){rNFCONF=(1<<15)|(1<<14)|(1<<13)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);//11111xxxrxxx,rxxx//EnrrECCRnFCE=HtACLStWRPH0tWRPH1nf_reset;}//-------------------------------------------------------------------voidnf_read(unsignedintsrc_addr,unsignedchar*desc_addr,intsize){inti;unsignedintcolumn_addr=src_addr%512;//columnaddressunsignedint_address=(src_addr>>9);//addrressunsignedchar*buf=desc_addr;while((unsignedint)buf<(unsignedint)(desc_addr)+size){NF_nFCE_L;//enablechipnand_flash*/if(column_addr>255)//2endhalftNF_CMD(0x01);//Read2command.cmd0x01:Readcommand(startfrom2endhalf)elseNF_CMD(0x00);//1sthalft?NF_ADDR(column_addr&0xff);//ColumnAddressNF_ADDR(_address&0xff);//AddressNF_ADDR((_addre