Nand Flash数据存储规则与数据读写方法(三)

谈到Nand Flash的数据存储方式，关于NAND Flash的数据读写方法方面的文章不多，这篇文章详细讲述了Nand Flash数据存储方式和数据读写方法，并用具体的芯片为例作了详细的解释。

    下面是源代码：
/* 
本代码只属于交流学习，不得用于商业开发
*/
#include "s3c2410.h"
#include "nand_flash.h"
static unsigned char seBuf[16]={0xff};
//--------------------------------------------------------------------------------------
unsigned short nf_checkId(void)
{
int i;
unsigned short id;
NF_nFCE_L(); //chip enable

NF_CMD(0x90); //Read ID
NF_ADDR(0x0);
for(i=0;i<10;i++); //wait tWB(100ns)

id=NF_RDDATA()<<8; // Maker code(K9S1208V:0xec)
id|=NF_RDDATA(); // Devide code(K9S1208V:0x76)

NF_nFCE_H(); //chip enable
return id;
}
//--------------------------------------------------------------------------------------
static void nf_reset(void)
{
int i;
NF_nFCE_L(); //chip enable
NF_CMD(0xFF); //reset command
for(i=0;i<10;i++); //tWB = 100ns.
NF_WAITRB(); //wait 200~500us;
NF_nFCE_H(); //chip disable
}
//--------------------------------------------------------------------------------------
void nf_init(void)
{
rNFCONF=(1<<15)|(1<<14)|(1<<13)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);
// 1 1 1 1 1 xxx r xxx, r xxx
// En r r ECCR nFCE=H tACLS tWRPH0 tWRPH1
nf_reset();
}
//--------------------------------------------------------------------------------------

void nf_read(unsigned int src_addr,unsigned char *desc_addr,int size)
{
int i;
unsigned int column_addr = src_addr % 512; // column address
unsigned int page_address = (src_addr >> 9); // page addrress
unsigned char *buf = desc_addr;
while((unsigned int)buf < (unsigned int)(desc_addr) + size)
{
NF_nFCE_L(); // enable chip

/*NF_ADDR和NF_CMD为nand_flash的地址和命令寄存器的解引用*/
if(column_addr > 255) // 2end halft
NF_CMD(0x01); // Read2 command. cmd 0x01: Read command(start from 2end half page)
else
NF_CMD(0x00); // 1st halft?

NF_ADDR(column_addr & 0xff); // Column Address
NF_ADDR(page_address & 0xff); // Page Address
NF_ADDR((page_address >> & 0xff); // ...
NF_ADDR((page_address >> 16) & 0xff); // ..
for(i = 0; i < 10; i++); // wait tWB(100ns)/////??????
NF_WAITRB(); // Wait tR(max 12us)

// Read from main area
for(i = column_addr; i < 512; i++)
{
*buf++= NF_RDDATA();
}
NF_nFCE_H(); // disable chip
column_addr = 0;
page_address++;
}
return ;
}