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)
NAND FLASH读写
