NAND FLASH读写.doc

NAND FLASH读写HY27UF081G2A:1Gbit (128Mx8bit / 64Mx16bit) NAND Flash Memory设备操作:3.1 Page Read.打开电源之后，芯片默认处于读状态。也可以在写入4字节地址之后，写入命令00h和30h到命令寄存器，使能读操作。In two consecutive(连续) read operations, the second one does need 00h command, which four address cycles and 30h command initiates that operation. Second read operation always requires setup command if first read operation was executed(执行) using also random data(随机读取) out command.Two types of operations are available: random read. The random read mode is enabled when the page address is changed. The 2112 bytes (X8 device) or 1056 words (X16 device) of data within the selected page are transferred to the data registers in less than 25us(tR). The system controller(控制器) may detect(检测) the completion of this data transfer (tR) by analyzing(分析) the output of R/B pin. Once the data in a page is loaded into the data registers(一旦一页的数据被加载到数据寄存器中), they may be read out in 30ns cycle time (3.3V device) by sequentially pulsing RE. The repetitive(重复) high to low transitions of the RE clock make the device output the data starting from the selected column address up to the last column address.The device may output random data in a page instead of the consecutive sequential data by writing random data output command. The column address of next data, which is going to be out, may be changed to the address which follows random data output command.1.命令输入 Command Input (CLE=1，ALE=0)ALE(0),CE(0) - CLE(1) - WE(0)-Command(输入并保持),在Command 保持时拉高WE（1）WE上升沿锁存Command-CE(1)-CLE(0)-ALE(1)根据时序图所得示意程序伪码void write_com(uint8 com)ALE=0; CE=0; delay 20ns;CLE=1;delay 15ns; WE=0;delay 15ns; IO7-0=com;delay 5ns; WE=1;delay 15ns; CE=1; CLE=0; ALE=1;2.地址输入 Address Input（CLE=0，ALE=1）3.数据输入 Data Input (CLE=0，ALE=0)4.数据读出 Data Output (CLE=0，ALE=0)5.读状态寄存器(Read Status Register)6.页读取(Page Read)7.任意地址数据读取 (Random DATA Output)command 0x00-address 4字节（该页首地址）- command 0x30-判别忙信号delay15ns-顺序读取或者command0x05-address 2字节（所要读的数据所在地址）-开始读出数据注意：注意图中的Column Address 对应Dout N的地址,0x50后是2字节在该页中的地址页写入(Page Program)command 0x80 - address 4字节（该页首地址）-顺序写入最多2112字节-command 0x10结束写-判别忙信号-command 0x70读状态寄存器-IO0为0写成功任意地址数据写入(Random DATA Input)command 0x80 - address 4字节（该页首地址）-顺序写入或者command0x85-写入数据-command0x10结束写入-判别忙信号-command0x70读状态-IO0为0写成功复制写入(Copy-Back Program)这个模式下，可以不用外部存储介质，直接在芯片内部快速准确地完成数据的复制重写入。因为数据串行输入和re-Loading的时间消耗被去除了，所以系统的效率提高了。在一块数据块中的若干数据块需要更新而该数据块中剩余数据需要复制到新的指定的空闲数据块中时，这种好处就尤为明显的体现出来了。执行复制写入的操作是一种连续的不需要串行存取的页读操作且通过目标页的地址来复制写入。读操作通过“0x35”指令来使得源页中的全部2112字节（X8芯片）/1056字节（X16芯片）数据传入内部数据缓存BUFFER。一旦设备芯片返回空闲状态，这copy_back指令“0x85”和目标页的地址可以写入。在实际将数据写入目标页签需要写入写指令“0x10”来开始实际写数据操作.When there is a program-failure at Copy-Back operation, error is reported by pass/fail status. But, ifCopy-Back operations are accumulated over time, bit error due to charge loss is not checked by externalerror detection/correction scheme. For this reason, two bit error correction is recommended for the useof Copy-Back operation.（大意是如果有写入超时，那么以一次的PASS/FAIL位会丢失，所以在这个Copy_back program模式下需要有两位的PASS/FAIL位来做检测（一般情况下只有一位）注：page间的复制写入，只允许从奇数地址的页复制到奇数地址的页，或者从偶数地址的页复制的偶数地址的页（不是很明白）过程：1.先通过指令0X35+4字节地址位找到源页将其2112字节复制到内部BUFFER 2.通过指令0x85+4字节地址设定目标页地址 3.通过指令0X10开始复制数据读区ID(Read ID)Command 0x90-address 0x00 -读1st：制造商标号-2nd:器件标识符-3rd:内部晶片数量，存储单元类型，同时编程的页数-4th:页大小（除去剩余区域），剩余区域大小，块大小（除去剩余区域