上一节我们介绍过nand flash一些特性和基本的命令序列操作方法，下面我们看看如何擦除、写nand flash一、擦除nand flashk9f1208U0M是按块擦除nand flash 的，1 block = 32 page = 32 * 512 byte= 16KB这里有注意的是擦除的地址绝对要是块对其的，即addr % block == 0看看datasheet上面擦除block的时序代码如下://擦除一个block块int erase_one_block(int addr){int statu;addr = addr >> 9;WRITE_CMD(0x60);//setup cmdWRITE_ADDR(addr&0xff);//1st CycleWRITE_ADDR((addr >> 8)&0xff);//2st CycleWRITE_ADDR((addr >> 16)&0xff);//3rd CycleWRITE_CMD(0xd0);//erase cmdwhile(!NFREADY());//wait readystatu = read_statu();if((statu & 0x1) != 0)return -1;return 0;}/* * 对nand flash 的一个块进行擦除 * 1 page_size = 512 bye; * 1 block_size = 32 * page_size = 32 * 512 / 1024 = 16bye; */int nand_erase(int addr,int size){int n = size / BLOCK_SIZE;int i = 0;//判断是否是块对齐的地址if(addr % BLOCK_SIZE != 0){uart0_printf("The addr is invalid,must addr %% 16byte == 0.\r\n");return -1;}if(n n = 1;uart0_printf("Start %#x will %d blocks will be erased.\r\n",addr,n);NFChipEn();for(i = 1;i {if(erase_one_block(addr) uart0_printf("Erase failed.\r\n");uart0_printf("%d block is erased\r",i);addr = addr + BLOCK_SIZE;}uart0_printf("\n");NFChipDs();return 0;}关于状态的读取int read_statu(){int statu;WRITE_CMD(0x70);delay_mtime(1000);statu = READ_DATA();#ifdef _DEBUG_uart0_printf("statu = %#x.\r\n",statu);#endifreturn statu;}二、写nand flashk9f1208U0M是按页写nand flash 的，1 page = 512 byte这里有注意的是擦除的地址绝对要是页对其的，即addr % page == 0看看datasheet上面写一个页的时序代码如下://发送命令和地址int write_cmd_addr(int addr){int column_addr,page_address;column_addr = addr % PAGE_SIZE;page_address = addr >> 9;WRITE_CMD(0x80);WRITE_ADDR(column_addr & 0xff);WRITE_ADDR(page_address & 0xff);WRITE_ADDR((page_address >> 8) & 0xff);WRITE_ADDR((page_address >> 16) & 0xff);return 0;}/* *注意:不管你要写多少个字节，每次写占用的最少 *是一个页的大小。 */int write_nand_page(int addr,char str[]){int statu,new_addr = addr;int i = 0,j = 0;int nbyte = my_strlen(str),n;uart0_printf("write %d pages.\n",nbyte/PAGE_SIZE);if(addr % PAGE_SIZE != 0){uart0_printf("The addr is invalid.\r\n");return -1;}/* *不够一页的按一页处理 *超过一页的按两页处理 */n = nbyte / PAGE_SIZE;if(nbyte % PAGE_SIZE != 0) n ++;if(n NFChipEn();for(i = 0;i {write_cmd_addr(new_addr);for(j = 0;j {WRITE_DATA(*str);}WRITE_CMD(0x10);while(!NFREADY());statu = read_statu();if((statu & 0x1) != 0){uart0_printf("write error.\r\n");return -1;}new_addr += PAGE_SIZE;}#ifdef _DEBUG_uart0_printf("*str = %c n = %d nbyte = %d.\r\n",*str,n,nbyte);#endifuart0_printf("write %d bytes at addr : %#x.\r\n",nbyte,addr);NFChipDs();return ;}
