色婷婷AⅤ一区二区三区|亚洲精品第一国产综合亚AV|久久精品官方网视频|日本28视频香蕉

          新聞中心

          EEPW首頁 > 嵌入式系統(tǒng) > 設計應用 > ARM·Nand Flash的控制

          ARM·Nand Flash的控制

          作者: 時間:2016-11-24 來源:網(wǎng)絡 收藏
          【本章總結】
          個人覺得這章內(nèi)容過于復雜,只需要記住如果nand中4096的程序想要被拷貝出來執(zhí)行,就把這個代碼寫進去,紅色部分是真正的代碼,可以復制過去,直接使用,其他就不做了解了。聽了一個小時,這個老師講的也挺亂的,也沒有人能記住這么多東西吧。。。
          【head.S init.c main.c nand.c Makefile】
          代碼詳解,這里先把一部分代碼存放在NAND Flash 地址4096之后,當程序啟動后通過NAND Flash控制器將他們讀出來、執(zhí)行。
          注意:以前的代碼都小于4096,開發(fā)板啟動后他們被自動復制進“Steppingstone”;
          現(xiàn)在的代碼在4096之后,需要控制NAND Flash將他們讀出來、執(zhí)行
          【nand.lds】
          SECTIONS {
          firtst 0x00000000 : { head.o init.o nand.o}
          second 0x30000000 : AT(4096) { main.o }
          }
          對于這里,我是這樣理解的 。head.o init.o nand.o都放在Nand flash0地址處,0x0000 0000是他的鏈接地址,也就是放在0x0000 0000處運行;mian.o存放在Nand flash 4096地址處,0x3000 0000是他的鏈接地址,也就是放在0x3000 0000處運行
          (可能也就是前一陣子看到的鏈接地址和加載地址的區(qū)別)
          當開發(fā)板啟動時,前4k的代碼被考進SRAM,所以我們需要在SRAM內(nèi)完成初始化和跳轉
          【head.s】
          SECTIONS {
          firtst 0x00000000 : { head.o init.o nand.o}
          second 0x30000000 : AT(4096) { main.o }
          } @******************************************************************************
          @ File:head.s
          @ 功能:設置SDRAM,將程序復制到SDRAM,然后跳到SDRAM繼續(xù)執(zhí)行
          @******************************************************************************
          .text
          .global _start
          _start:
          @函數(shù)disable_watch_dog, memsetup, init_nand, nand_read_ll在init.c中定義
          ldr sp, =4096 @設置堆棧
          bl disable_watch_dog @關WATCH DOG
          bl memsetup @初始化SDRAM
          bl nand_init @初始化NAND Flash
          @將NAND Flash中地址4096開始的1024字節(jié)代碼(main.c編譯得到)復制到SDRAM中
          @nand_read_ll函數(shù)需要3個參數(shù):
          ldr r0, =0x30000000 @1. 目標地址=0x30000000,這是SDRAM的起始地址
          mov r1, #4096 @2. 源地址 = 4096,連接的時候,main.c中的代碼都存在NAND Flash地址4096開始處
          mov r2, #2048 @3. 復制長度= 2048(bytes),對于本實驗的main.c,這是足夠了
          bl nand_read @調(diào)用C函數(shù)nand_read
          ldr sp, =0x34000000 @設置棧
          ldr lr, =halt_loop @設置返回地址
          ldr pc, =main @b指令和bl指令只能前后跳轉32M的范圍,所以這里使用向pc賦值的方法進行跳轉
          halt_loop:
          b halt_loop
          *對于這一串代碼,很多都是前面學過的知識,這里我們只關注配置Nand的紅色代碼
          bl nand_init
          *目標地址,源地址,目標長度
          ldr r0, =0x30000000 @1. 目標地址=0x30000000,這是SDRAM的起始地址
          mov r1, #4096 @2. 源地址 = 4096,連接的時候,main.c中的代碼都存在NAND Flash地 址4096開始處
          mov r2, #2048 @3. 復制長度= 2048(bytes),對于本實驗的main.c,這是足夠了
          bl nand_read @調(diào)用C函數(shù)nand_read
          這里我們可以跳轉到nand_read中可以看一下
          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 ;
          }
          #else
          if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
          return ;
          }
          #endif
          nand_select_chip();
          for(i=start_addr; i < (start_addr + size);) {
          write_cmd(0);
          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++;
          }
          }
          【nand.c】
          #define LARGER_NAND_PAGE
          #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;
          typedef struct {
          S3C24X0_REG32 NFCONF;
          S3C24X0_REG32 NFCMD;
          S3C24X0_REG32 NFADDR;
          S3C24X0_REG32 NFDATA;
          S3C24X0_REG32 NFSTAT;
          S3C24X0_REG32 NFECC;
          } S3C2410_NAND;
          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;
          void nand_init(void);
          void nand_read(unsigned char *buf, unsigned long start_addr, int size);
          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);
          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();
          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);
          static void s3c2410_nand_reset(void)
          {
          s3c2410_nand_select_chip();
          s3c2410_write_cmd(0xff); // 復位命令
          s3c2410_wait_idle();
          s3c2410_nand_deselect_chip();
          }
          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++);
          }
          static void s3c2410_nand_select_chip(void)
          {
          int i;
          s3c2410nand->NFCONF &= ~(1<<11);
          for(i=0; i<10; i++);
          }
          static void s3c2410_nand_deselect_chip(void)
          {
          s3c2410nand->NFCONF |= (1<<11);
          }
          static void s3c2410_write_cmd(int cmd)
          {
          volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFCMD;
          *p = cmd;
          }
          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++);
          }
          static unsigned char s3c2410_read_data(void)
          {
          volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFDATA;
          return *p;
          }
          static void s3c2440_nand_reset(void)
          {
          s3c2440_nand_select_chip();
          s3c2440_write_cmd(0xff); // 復位命令
          s3c2440_wait_idle();
          s3c2440_nand_deselect_chip();
          }
          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++);
          }
          static void s3c2440_nand_select_chip(void)
          {
          int i;
          s3c2440nand->NFCONT &= ~(1<<1);
          for(i=0; i<10; i++);
          }
          static void s3c2440_nand_deselect_chip(void)
          {
          s3c2440nand->NFCONT |= (1<<1);
          }
          static void s3c2440_write_cmd(int cmd)
          {
          volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFCMD;
          *p = cmd;
          }
          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++);
          }

          上一頁 1 2 下一頁

          關鍵詞: ARMNandFlas

          評論


          技術專區(qū)

          關閉