Nor flash 原理及硬件操作（2）

回顾：

其实Nor flash的硬件操作---->Nor flash的内存操作---->Nor flash地址和数据操作。

所以，对Nor flash手册的解读至关重要！！！《MX29LV800BT/BB（推荐）/MX29LV160D T/B》

对了，u-boot是裸机开发的集大成者，虚心学习总是没错的。

 

 

 程序框架：

void nor_flash_test(void)
{
    char c;
    
    /*打印菜单，供我们选择测试内容*/
    myprintf("\n\r");
    myprintf("[s]  Scan nor flash\n\r");
    myprintf("[e]  Erase nor flash\n\r");
    myprintf("[w]  Write nor flash\n\r");
    myprintf("[r]  Read nor flash\n\r");
    myprintf("[q]  Quit\n\r");
    myprintf("Enter selection:");

    c = getchar();
    myprintf("%c\n\r",c);

    /*测试内容：
     *1.识别nor_falsh
     *2.擦出nor_flash某扇区
     *3.编写某个地址
     *4.读某个地址
     */
    switch(c)
        {
            case 's':
            case 'S':
            do_scan_nor_flash();
            break;

            case 'e':
            case 'E':
            do_erase_nor_flash();
            break;

            case 'w':
            case 'W':
            do_write_nor_flash();
            break;

            case 'r':
            case 'R':
            do_read_nor_flash();
            break;

            case 'q':
            case 'Q':
            return;　　//return直接返回到函数起始位置重新开始执行
            break;

            default:
            break;
            
        }
}

基本框架有了，接着我们就来完善每一个选择对应的被调函数：

再回忆一下，在Nor flash 原理及硬件操作（1）中，我们是如何对Nor flash的进行读/写的：

md.w addr        //读操作命令，参数
2 mw.w addr data   //写操作命令，参数 

所以，我们最好首先分别封装读/写函数，然后提供给其他的函数使用：

 #define　　NOR_FLASH_BASE　　0　　//Nor flash的基地址为0
... 

 1　unsigned int nor_read_word(unsigned int base,unsigned int offset)
{
    volatile unsigned short *p = (volatile unsigned short *)(base + (offset<<1));
    return *p;
}

unsigned int nor_dat(unsigned int offset)
{
    return nor_read_word(NOR_FLASH_BASE, offset);
}

(1)do_scan_nor_flash函数

void do_scan_nor_flash(void)
{
    char str[4];
    unsigned int size;
    int regions,i;
    int region_info_base;
    int block_addr, blocks,block_size,j;
    int cnt;
    int vendor,device;

    /*打印厂家ID*/
    nor_cmd(0x555,0xaa);    //解锁
    nor_cmd(0x2aa,0x55);
    nor_cmd(0x555,0x90);

    vendor = nor_dat(0);    //读ID
    device = nor_dat(1);

    nor_cmd(0,0xf0);        //复位，退出读ID操作
    
    
    nor_cmd(0x55,0x98);    //进入CFI模式，读取其他的信息

    str[0] = nor_dat(0x10);  //读QRY确认进入CFI模式
    str[1] = nor_dat(0x11);
    str[2] = nor_dat(0x12);
    str[3] = '\0';
    myprintf("str = %s\n\r",str);

    /*打印容量*/
    size = (1<<nor_dat(0x27));　　//1个数左移n位，就等于将这个数乘以2的n次方
    myprintf("vendor id = 0x%x,device id = 0x%x,Nor flash size = %dM\n\r",vendor,device,size/(1024*1024));

    /*打印各个扇区的起始地址*/
    regions = nor_dat(0x2c);
    region_info_base = 0x2d;
    block_addr = 0;
    myprintf("Block/sector start Address:\n\r");
    cnt = 0;
    for(i=0; i<regions; i++)
        {
            blocks = 1 + (nor_dat(region_info_base) + (nor_dat(region_info_base+1)<<8));
            block_size = 256 * (nor_dat(region_info_base+2) + (nor_dat(region_info_base+3)<<8));
            region_info_base += 4;
            
            for(j=0; j<blocks; j++)
                {
                    /*打印每个block的起始地址*/
                    printHex(block_addr);
                    putchar(' ');
                    block_addr += block_size;
                    cnt++;
                    if(cnt % 5 == 0 )
                        {
                            myprintf("\n\r");
                        }
                }
        }
    myprintf("\n\r");
    /*退出CFI模式*/
    nor_cmd(0,0xf0);
}

(bits:15-0):　2F 0x00　30 0x01　  所以要将2F、30合成低16位数0x0100

（(bits:15-0) + 1）=blocks

(bits:31-16):　2D 0x0f　2E 0x00　所以要将2D、2E合成高16位数0x000f

(bits:31-16)*256=block_size

 

(2)do_erase_nor_flash函数

void do_erase_nor_flash(void )
{    
    unsigned int addr;

    /*获得地址*/
    myprintf("Enter the address of sector to erase: ");
    addr = get_uint();　　//string_utils.c里面的函数，可以直接获得标准输入

    myprintf("Erase ...\n\r");

    nor_cmd(0x555,0xaa);    //解锁
    nor_cmd(0x2aa,0x55);
    nor_cmd(0x555,0x80);    //擦除
    
    nor_cmd(0x555,0xaa);    //再次解锁
    nor_cmd(0x2aa,0x55);
    
18　　　/*扇区地址写入0x30*/
19　　　nor_cmd(addr>>1,0x30);  /*Nor flash 16bits*/　//一个数右移n位，就等于这个数除以2的n次方
    wait_ready(addr);
　　 myprintf("Erasing finished!");
}

(3)由于读/写/擦除都需要时间，所以我们需要设置延时，但是延时又无法保证精准，可能会浪费系统时间。

我们查看手册，看是否有更好的解决办法：

 

 

 于是wait_ready函数：

void wait_ready(unsigned int addr)
{
    unsigned int val;
    unsigned int pre;
    
    pre = nor_dat(addr>>1);　　//先读一次数据
    val = nor_dat(addr>>1);　　//再读一次数据

    while((val & (1<<6)) != (pre & (1<<6)))　　//若两次读取结果不一致，说明说明数据还在变化，继续等待
        {
            pre = val;　　//继续读取
            val = nor_dat(addr>>1);　　
        }
}

(4)do_read_nor_flash函数：

void do_read_nor_flash(void )
{
    unsigned int addr;
    volatile unsigned char *p;
    int i,j;
    unsigned char c;
    unsigned char str[16];

    /*获得地址*/
    myprintf("Enter the address to read: ");
    addr = get_uint();

    p = (volatile unsigned char *)addr;

    myprintf("Data :\n\r");
    
    /*长度固定为64Bytes*/
    for(i=0; i<4; i++)
        {
            /*每行打印16个字符数据*/
        for(j=0; j<16;j++)
            {
                /*先打印数值*/
                c = *p++;
                str[j] = c;
                myprintf("%02x",c);　　//格式控制显示结果为2个字节，高位补零
                myprintf(" ");
            }
    
        myprintf("   ;");
        for(j=0; j<16;j++)
            {
                /*后打印不可显示字符*/ 
                if(str[j] < 0x20 || str[j] > 0x7e)　　//ASCII码 可显示字符0x20~0x7e
                    {
                        putchar('.');
                    }
                else
                    {
                        putchar(str[j]);
                    }
            }
        myprintf("\n\r");
        }
}

（5）do_write_nor_flash函数：

void do_write_nor_flash(void )
{
    unsigned int addr;
    unsigned char str[100];
    int i,j;
    unsigned int val;

    /*获得地址*/
    myprintf("Enter the address of sector to write: ");
    addr = get_uint();

    myprintf("Enter the string to write: ");
    gets(str);

    myprintf("Writing ...\n\r");

    /*str[0],str[1]==>>16bit*/
    /*str[2],str[3]==>>16bit*/
    
    i=0;
    j=1;
    while(str[i] && str[j])
        {
            val = str[i] + (str[j]<<8);　　//str[0],str[1]合并成16bit的数据，依次类推...

            /*烧写*/
            nor_cmd(0x555,0xaa);    //解锁
            nor_cmd(0x2aa,0x55);
            nor_cmd(0x555,0xa0);    //发出烧写信号
            nor_cmd(addr>>1,val);

            /*等待烧写完成，读数据Q6无变化时表示结束*/
            wait_ready(addr);

            i += 2;　　//合并str[2],str[3]
            j += 2;
            addr += 2;
        }

        val = str[i];　　//10 50 63 00 1f ff ff
    
    nor_cmd(0x555,0xaa);    //解锁
    nor_cmd(0x2aa,0x55);
    nor_cmd(0x555,0xa0);    //发出烧写信号
    nor_cmd(addr>>1,val);　　//写完最后一个高位数据
    /*等待烧写完成，读数据Q6无变化时表示结束*/
    wait_ready(addr);
48　　
49　　　myprintf("Writting finished!");
    
}

代码展示：

#include "myprintf.h"
#include "string_utils.h"

#define    NOR_FLASH_BASE        0

/*进入nor flash的CFI模式
 *读取各类信息
 */

/*55H 98*/
/*地址(0+(0x55<<1))写0x98*/
void nor_write_word(unsigned int base,unsigned int offset,unsigned short val)
{
    volatile unsigned short *p = (volatile unsigned short *)(base + (offset<<1));
    *p = val;
}

/*offset是基于Nor flash的角度*/
void nor_cmd(unsigned int offset,unsigned int cmd)
{
    nor_write_word(NOR_FLASH_BASE, offset, cmd);
}

unsigned int nor_read_word(unsigned int base,unsigned int offset)
{
    volatile unsigned short *p = (volatile unsigned short *)(base + (offset<<1));
    return *p;
}

unsigned int nor_dat(unsigned int offset)
{
    return nor_read_word(NOR_FLASH_BASE, offset);
}

void wait_ready(unsigned int addr)
{
    unsigned int val;
    unsigned int pre;
    
    pre = nor_dat(addr>>1);
    val = nor_dat(addr>>1);

    while((val & (1<<6)) != (pre & (1<<6)))
        {
            pre = val;
            val = nor_dat(addr>>1);
        }
}

void do_scan_nor_flash(void)
{
    char str[4];
    unsigned int size;
    int regions,i;
    int region_info_base;
    int block_addr, blocks,block_size,j;
    int cnt;
    int vendor,device;

    /*打印厂家ID*/
    nor_cmd(0x555,0xaa);    //解锁
    nor_cmd(0x2aa,0x55);
    nor_cmd(0x555,0x90);

    vendor = nor_dat(0);    //读ID
    device = nor_dat(1);

    nor_cmd(0,0xf0);        //复位
    
    
    nor_cmd(0x55,0x98);    //进入CFI模式

    str[0] = nor_dat(0x10);
    str[1] = nor_dat(0x11);
    str[2] = nor_dat(0x12);
    str[3] = '\0';
    myprintf("str = %s\n\r",str);

    /*打印容量*/
    size = (1<<nor_dat(0x27));
    myprintf("vendor id = 0x%x,device id = 0x%x,Nor flash size = %dM\n\r",vendor,device,size/(1024*1024));

    /*打印各个扇区的起始地址*/
    regions = nor_dat(0x2c);
    region_info_base = 0x2d;
    block_addr = 0;
    myprintf("Block/sector start Address:\n\r");
    cnt = 0;
    for(i=0; i<regions; i++)
        {
            blocks = 1 + (nor_dat(region_info_base) + (nor_dat(region_info_base+1)<<8));
            block_size = 256 * (nor_dat(region_info_base+2) + (nor_dat(region_info_base+3)<<8));
            region_info_base += 4;
            
            for(j=0; j<blocks; j++)
                {
                    /*打印每个block的起始地址*/
                    printHex(block_addr);
                    putchar(' ');
                    block_addr += block_size;
                    cnt++;
                    if(cnt % 5 == 0 )
                        {
                            myprintf("\n\r");
                        }
                }
        }
    myprintf("\n\r");
    /*退出CFI模式*/
    nor_cmd(0,0xf0);
}

void do_erase_nor_flash(void )
{    
    unsigned int addr;

    /*获得地址*/
    myprintf("Enter the address of sector to erase: ");
    addr = get_uint();

    myprintf("Erase ...\n\r");

    nor_cmd(0x555,0xaa);    //解锁
    nor_cmd(0x2aa,0x55);
    nor_cmd(0x555,0x80);    //擦除
    
    nor_cmd(0x555,0xaa);    //再次解锁
    nor_cmd(0x2aa,0x55);
    nor_cmd(addr>>1,0x30);    //扇区地址写入0x30
    wait_ready(addr);

    myprintf("Erase finished!");
}

void do_write_nor_flash(void )
{
    unsigned int addr;
    unsigned char str[100];
    int i,j;
    unsigned int val;

    /*获得地址*/
    myprintf("Enter the address of sector to write: ");
    addr = get_uint();

    myprintf("Enter the string to write: ");
    gets(str);

    myprintf("Writing ...\n\r");

    /*str[0],str[1]==>>16bit*/
    /*str[2],str[3]==>>16bit*/
    
    i=0;
    j=1;
    while(str[i] && str[j])
        {
            val = str[i] + (str[j]<<8);

            /*烧写*/
            nor_cmd(0x555,0xaa);    //解锁
            nor_cmd(0x2aa,0x55);
            nor_cmd(0x555,0xa0);    //发出烧写信号
            nor_cmd(addr>>1,val);

            /*等待烧写完成，读数据Q6无变化时表示结束*/
            wait_ready(addr);

            i += 2;
            j += 2;
            addr += 2;
        }

        val = str[i];    
    
    nor_cmd(0x555,0xaa);    //解锁
    nor_cmd(0x2aa,0x55);
    nor_cmd(0x555,0xa0);    //发出烧写信号
    nor_cmd(addr>>1,val);
    /*等待烧写完成，读数据Q6无变化时表示结束*/
    wait_ready(addr);

    myprintf("Writing finished!");
    
}

void do_read_nor_flash(void )
{
    unsigned int addr;
    volatile unsigned char *p;
    int i,j;
    unsigned char c;
    unsigned char str[16];

    /*获得地址*/
    myprintf("Enter the address to read: ");
    addr = get_uint();

    p = (volatile unsigned char *)addr;

    myprintf("Data :\n\r");
    
    /*长度固定为64Bytes*/
    for(i=0; i<4; i++)
        {
            /*每行打印16个字符数据*/
        for(j=0; j<16;j++)
            {
                /*先打印数值*/
                c = *p++;
                str[j] = c;
                myprintf("%02x",c);
                myprintf(" ");
            }
    
        myprintf("   ;");
        for(j=0; j<16;j++)
            {
                /*后打印不可显示字符*/
                if(str[j] < 0x20 || str[j] > 0x7e)
                    {
                        putchar('.');
                    }
                else
                    {
                        putchar(str[j]);
                    }
            }
        myprintf("\n\r");
        }
}

void nor_flash_test(void)
{
    char c;
    
    /*打印菜单，供我们选择测试内容*/
    myprintf("\n\r");
    myprintf("[s]  Scan nor flash\n\r");
    myprintf("[e]  Erase nor flash\n\r");
    myprintf("[w]  Write nor flash\n\r");
    myprintf("[r]  Read nor flash\n\r");
    myprintf("[q]  Quit\n\r");
    myprintf("Enter selection:");

    c = getchar();
    myprintf("%c\n\r",c);

    /*测试内容：
    *1.识别nor_falsh
    *2.擦出nor_flash某扇区
    *3.编写某个地址
    *4.读某个地址
    */
    switch(c)
        {
            case 's':
            case 'S':
            do_scan_nor_flash();
            break;

            case 'e':
            case 'E':
            do_erase_nor_flash();
            break;

            case 'w':
            case 'W':
            do_write_nor_flash();
            break;

            case 'r':
            case 'R':
            do_read_nor_flash();
            break;

            case 'q':
            case 'Q':
            return;
            break;

            default:
            break;
            
        }
}