裸奔之写、擦除nandflash

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 flash

k9f1208U0M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 cmd

WRITE_ADDR(addr&0xff);//1st Cycle

WRITE_ADDR((addr >> 8)&0xff);//2st Cycle

WRITE_ADDR((addr >> 16)&0xff);//3rd Cycle

WRITE_CMD(0xd0);//erase cmd

while(!NFREADY());//wait ready

statu = 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 < 1) 

n = 1;

uart0_printf("Start %#x will %d blocks will be erased.\r\n",addr,n);

NFChipEn();

for(i = 1;i <= n;i ++)

{

if(erase_one_block(addr) < 0)

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);

#endif

return statu;

}

二、写nand flash

k9f1208U0M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 < 1) n = 1;

NFChipEn();

for(i = 0;i < n;i ++)

{

write_cmd_addr(new_addr);

for(j = 0;j < PAGE_SIZE && *str != '\0';j ++,str ++)

{

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);

#endif

uart0_printf("write %d bytes at addr : %#x.\r\n",nbyte,addr);

NFChipDs();

return ;

}