目的：了解nandflash的接口，通过nandflash控制器熟悉nand的控制。
先上图：
我的nandflash是256M的，nand的一页为2k+64byte，1块 = 64页，也就是有两块。
数据线地址线就只有8位，那怎么访问那么大的地址呢，可以多次发，如下：
nand的接口电路：
分析下各个引脚的功能：LDATAn 命令、地址、数据总线，CLE 命令锁存使能，ALE 地址锁存使能 nFCE 片选使能，nFRE 读使能，nFWE 写使能，wp 写保护。
RnB 就绪/忙输出。
命令设置：
TACLS ：CLE & ALE duration setting value (0~3)发生读写使能前，地址/命令使能设置的持续时间值。
TWRPH0 ：TWRPH0 duration setting value (0~7) 发生读写使能持续的时间。
TWRPH1：TWRPH1 duration setting value (0~7) 写使能结束后，地址/命令使能持续的时间。
head.s：
@******************************************************************************
@ File：head.s
@ 功能：设置SDRAM，将程序复制到SDRAM，然后跳到SDRAM继续执行
@******************************************************************************
.text
.global _start
_start: @函数disable_watch_dog, memsetup, init_nand, nand_read_ll在init.c中定义
ldr sp, =4096 @设置堆栈
bl disable_watch_dog @关WATCH DOG
bl memsetup @初始化SDRAM
bl nand_init @初始化NAND Flash
@将NAND Flash中地址4096开始的1024字节代码(main.c编译得到)复制到SDRAM中
@nand_read_ll函数需要3个参数：
ldr r0, =0x30000000 @1. 目标地址=0x30000000，这是SDRAM的起始地址
mov r1, #4096 @2. 源地址 = 4096，连接的时候，main.c中的代码都存在NAND Flash地址4096开始处
mov r2, #2048 @3. 复制长度= 2048(bytes)，对于本实验的main.c，这是足够了
bl nand_read @调用C函数nand_read
ldr sp, =0x34000000 @设置栈
ldr lr, =halt_loop @设置返回地址
ldr pc, =main @b指令和bl指令只能前后跳转32M的范围，所以这里使用向pc赋值的方法进行跳转
halt_loop:
b halt_loop
初始化函数：
/* WOTCH DOG register */
#define WTCON
(*(volatile unsigned long *)0x53000000)
/* SDRAM regisers */
#define MEM_CTL_BASE0x48000000
void disable_watch_dog();
void memsetup();
/*上电后，WATCH DOG默认是开着的，要把它关掉 */
void disable_watch_dog()
{
WTCON = 0;
}
/* 设置控制SDRAM的13个寄存器 */
void memsetup()
{
int i = 0;
unsigned long *p = (unsigned long *)MEM_CTL_BASE;
/* SDRAM 13个寄存器的值 */
unsigned long const mem_cfg_val[]={ 0x22011110, //BWSCON
0x00000700, //BANKCON0
0x00000700, //BANKCON1
0x00000700, //BANKCON2
0x00000700, //BANKCON3
0x00000700, //BANKCON4
0x00000700, //BANKCON5
0x00018005, //BANKCON6
0x00018005, //BANKCON7
0x008C07A3, //REFRESH
0x000000B1, //BANKSIZE
0x00000030, //MRSRB6
0x00000030, //MRSRB7
};
for(; i < 13; i++)
p[i] = mem_cfg_val[i];
}
nand.c：
#define GSTATUS1 (*(volatile unsigned int *)0x560000B0)
#define BUSY 1
#define NAND_SECTOR_SIZE 512
#define NAND_BLOCK_MASK (NAND_SECTOR_SIZE - 1)
#define NAND_SECTOR_SIZE_LP 2048
#define NAND_BLOCK_MASK_LP (NAND_SECTOR_SIZE_LP - 1)
typedef unsigned int S3C24X0_REG32;
/* NAND FLASH (see S3C2410 manual chapter 6) */
typedef struct {
S3C24X0_REG32 NFCONF;
S3C24X0_REG32 NFCMD;
S3C24X0_REG32 NFADDR;
S3C24X0_REG32 NFDATA;
S3C24X0_REG32 NFSTAT;
S3C24X0_REG32 NFECC;
} S3C2410_NAND;
/* NAND FLASH (see S3C2440 manual chapter 6, www.100ask.net) */
typedef struct {
S3C24X0_REG32 NFCONF;
S3C24X0_REG32 NFCONT;
S3C24X0_REG32 NFCMD;
S3C24X0_REG32 NFADDR;
S3C24X0_REG32 NFDATA;
S3C24X0_REG32 NFMECCD0;
S3C24X0_REG32 NFMECCD1;
S3C24X0_REG32 NFSECCD;
S3C24X0_REG32 NFSTAT;
S3C24X0_REG32 NFESTAT0;
S3C24X0_REG32 NFESTAT1;
S3C24X0_REG32 NFMECC0;
S3C24X0_REG32 NFMECC1;
S3C24X0_REG32 NFSECC;
S3C24X0_REG32 NFSBLK;
S3C24X0_REG32 NFEBLK;
} S3C2440_NAND;
typedef struct {
void (*nand_reset)(void);
void (*wait_idle)(void);
void (*nand_select_chip)(void);
void (*nand_deselect_chip)(void);
void (*write_cmd)(int cmd);
void (*write_addr)(unsigned int addr);
unsigned char (*read_data)(void);
}t_nand_chip;
static S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
static S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;
static t_nand_chip nand_chip;
/* 供外部调用的函数 */
void nand_init(void);
void nand_read(unsigned char *buf, unsigned long start_addr, int size);
/* NAND Flash操作的总入口, 它们将调用S3C2410或S3C2440的相应函数 */
static void nand_reset(void);
static void wait_idle(void);
static void nand_select_chip(void);
static void nand_deselect_chip(void);
static void write_cmd(int cmd);
static void write_addr(unsigned int addr);
static unsigned char read_data(void);
/* S3C2410的NAND Flash处理函数 */
static void s3c2410_nand_reset(void);
static void s3c2410_wait_idle(void);
static void s3c2410_nand_select_chip(void);
static void s3c2410_nand_deselect_chip(void);
static void s3c2410_write_cmd(int cmd);
static void s3c2410_write_addr(unsigned int addr);
static unsigned char s3c2410_read_data();
/* S3C2440的NAND Flash处理函数 */
static void s3c2440_nand_reset(void);
static void s3c2440_wait_idle(void);
static void s3c2440_nand_select_chip(void);
static void s3c2440_nand_deselect_chip(void);
static void s3c2440_write_cmd(int cmd);
static void s3c2440_write_addr(unsigned int addr);
static unsigned char s3c2440_read_data(void);
/* S3C2410的NAND Flash操作函数 */
/* 复位 */
static void s3c2410_nand_reset(void)
{
s3c2410_nand_select_chip();
s3c2410_write_cmd(0xff); // 复位命令
s3c2410_wait_idle();
s3c2410_nand_deselect_chip();
}
/* 等待NAND Flash就绪 */
static void s3c2410_wait_idle(void)
{
int i;
volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFSTAT;
while(!(*p & BUSY))
for(i=0; i<10; i++);
}
/* 发出片选信号 */
static void s3c2410_nand_select_chip(void)
{
int i;
s3c2410nand->NFCONF &= ~(1<<11);
for(i=0; i<10; i++);
}
/* 取消片选信号 */
static void s3c2410_nand_deselect_chip(void)
{
s3c2410nand->NFCONF |= (1<<11);
}
/* 发出命令 */
static void s3c2410_write_cmd(int cmd)
{
volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFCMD;
*p = cmd;
}
/* 发出地址 */
static void s3c2410_write_addr(unsigned int addr)
{
int i;
volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFADDR;
*p = addr & 0xff;
for(i=0; i<10; i++);
*p = (addr >> 9) & 0xff;
for(i=0; i<10; i++);
*p = (addr >> 17) & 0xff;
for(i=0; i<10; i++);
*p = (addr >> 25) & 0xff;
for(i=0; i<10; i++);
}
/* 读取数据 */
static unsigned char s3c2410_read_data(void)
{
volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFDATA;
return *p;
}
/* S3C2440的NAND Flash操作函数 */
/* 复位 */
static void s3c2440_nand_reset(void)
{
s3c2440_nand_select_chip();
s3c2440_write_cmd(0xff); // 复位命令
s3c2440_wait_idle();
s3c2440_nand_deselect_chip();
}
/* 等待NAND Flash就绪 */
static void s3c2440_wait_idle(void)
{
int i;
volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFSTAT;
while(!(*p & BUSY))
for(i=0; i<10; i++);
}
/* 发出片选信号 */
static void s3c2440_nand_select_chip(void)
{
int i;
s3c2440nand->NFCONT &= ~(1<<1);
for(i=0; i<10; i++);
}
/* 取消片选信号 */
static void s3c2440_nand_deselect_chip(void)
{
s3c2440nand->NFCONT |= (1<<1);
}
/* 发出命令 */
static void s3c2440_write_cmd(int cmd)
{
volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFCMD;
*p = cmd;
}
/* 发出地址 */
static void s3c2440_write_addr(unsigned int addr)
{
int i;
volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFADDR;
*p = addr & 0xff;
for(i=0; i<10; i++);
*p = (addr >> 9) & 0xff;
for(i=0; i<10; i++);
*p = (addr >> 17) & 0xff;
for(i=0; i<10; i++);
*p = (addr >> 25) & 0xff;
for(i=0; i<10; i++);
}
static void s3c2440_write_addr_lp(unsigned int addr)
{
int i;
volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFADDR;
int col, page;
col = addr & NAND_BLOCK_MASK_LP;
page = addr / NAND_SECTOR_SIZE_LP;
*p = col & 0xff;/* Column Address A0~A7 */
for(i=0; i<10; i++);
*p = (col >> 8) & 0x0f;
/* Column Address A8~A11 */
for(i=0; i<10; i++);
*p = page & 0xff;/* Row Address A12~A19 */
for(i=0; i<10; i++);
*p = (page >> 8) & 0xff;/* Row Address A20~A27 */
for(i=0; i<10; i++);
*p = (page >> 16) & 0x03;/* Row Address A28~A29 */
for(i=0; i<10; i++);
}
/* 读取数据 */
static unsigned char s3c2440_read_data(void)
{
volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFDATA;
return *p;
}
/* 在第一次使用NAND Flash前，复位一下NAND Flash */
static void nand_reset(void)
{
nand_chip.nand_reset();
}
static void wait_idle(void)
{
nand_chip.wait_idle();
}
static void nand_select_chip(void)
{
int i;
nand_chip.nand_select_chip();
for(i=0; i<10; i++);
}
static void nand_deselect_chip(void)
{
nand_chip.nand_deselect_chip();
}
static void write_cmd(int cmd)
{
nand_chip.write_cmd(cmd);
}
static void write_addr(unsigned int addr)
{
nand_chip.write_addr(addr);
}
static unsigned char read_data(void)
{
return nand_chip.read_data();
}
/* 初始化NAND Flash */
void nand_init(void)
{
#define TACLS 0
#define TWRPH0 3
#define TWRPH1 0
/* 判断是S3C2410还是S3C2440 */
if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
{
nand_chip.nand_reset = s3c2410_nand_reset;
nand_chip.wait_idle = s3c2410_wait_idle;
nand_chip.nand_select_chip = s3c2410_nand_select_chip;
nand_chip.nand_deselect_chip = s3c2410_nand_deselect_chip;
nand_chip.write_cmd = s3c2410_write_cmd;
nand_chip.write_addr = s3c2410_write_addr;
nand_chip.read_data = s3c2410_read_data;
/* 使能NAND Flash控制器, 初始化ECC, 禁止片选, 设置时序 */
s3c2410nand->NFCONF = (1<<15)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);
}
else
{
nand_chip.nand_reset = s3c2440_nand_reset;
nand_chip.wait_idle = s3c2440_wait_idle;
nand_chip.nand_select_chip = s3c2440_nand_select_chip;
nand_chip.nand_deselect_chip = s3c2440_nand_deselect_chip;
nand_chip.write_cmd = s3c2440_write_cmd;
#ifdef LARGER_NAND_PAGE
nand_chip.write_addr = s3c2440_write_addr_lp;
#else
nand_chip.write_addr= s3c2440_write_addr;
#endif
nand_chip.read_data = s3c2440_read_data;
/* 设置时序 */
s3c2440nand->NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);
/* 使能NAND Flash控制器, 初始化ECC, 禁止片选 */
s3c2440nand->NFCONT = (1<<4)|(1<<1)|(1<<0);
}
/* 复位NAND Flash */
nand_reset();
}
/* 读函数 */
void nand_read(unsigned char *buf, unsigned long start_addr, int size)
{
int i, j;
#ifdef LARGER_NAND_PAGE
if ((start_addr & NAND_BLOCK_MASK_LP) || (size & NAND_BLOCK_MASK_LP)) {
return ; /* 地址或长度不对齐 */
}
#else
if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
return ; /* 地址或长度不对齐 */
}
#endif
/* 选中芯片 */
nand_select_chip();
for(i=start_addr; i < (start_addr + size);) {
/* 发出READ0命令 */
write_cmd(0);
/* Write Address */
write_addr(i);
#ifdef LARGER_NAND_PAGE
write_cmd(0x30);
#endif
wait_idle();
#ifdef LARGER_NAND_PAGE
for(j=0; j < NAND_SECTOR_SIZE_LP; j++, i++) {
#else
for(j=0; j < NAND_SECTOR_SIZE; j++, i++) {
#endif
*buf = read_data();
buf++;
}
}
/* 取消片选信号 */
nand_deselect_chip();
return ;
}
nand.lds
SECTIONS {
firtst 0x00000000 : { head.o init.o nand.o}
second 0x30000000 : AT(4096) { main.o }
}
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