1.2440结构图
对于2440来说，cpu可以直接发指令给SRAM、网卡、SDRAM、NOR FLASH，但无法直接控制NAND FLASH,必须由NAND FLASH控制器来操作NAND FLASH，但为什么我们的裸机程序烧入NAND FLASH还可以运行呢？
这就引入了重定位机制，当程序是NAND启动时，2440会把前4K的代码拷贝到SRAM中运行（由硬件完成拷贝），然后CPU从0地址开始运行（0地址对应的是SRAM）。如果烧入NAND FLASH中的程序超过4K该怎么办呢？
如果程序大于4K，前面4K放入SRAM同时前4K的代码会把整个代码都读出来，放在SDRAM中，这就是重定位，重新确定程序的地址。
对于NOR启动来说CPU所对应的0地址是NOR FLASH的0地址，此时片内内存的基地址是0x40000000，所以此时NAND FLASH不可访问。
NOR FLASH的特点：可以像内存一样的读，但不能像内存一样的写，必须通过特定的指令来写，那么问题来了，如果程序中含有需要更改的全局变量或静态变量，他们存储在NOR上我们直接修改是无效的（局部变量存储在栈中，也就是内存中，可随时改变他的初始值），那我们想要修改全局变量或局部变量该怎么办呢？我们要把全局变量或静态变量放到SDRAM上重定位后运行
我们写个代码烧到nor上来测试一下
2.测试代码
（1）sdram.h
#ifndef _SDRAM_INIT
#define _SDRAM_INIT
void sdram_init(void);
int sdram_test(void);
#endif(2)sdram.c
#include "s3c2440_soc.h"
void sdram_init(void)
{
BWSCON = 0x22000000;
BANKCON6 = 0x18001;
BANKCON7= 0x18001;
REFRESH = 0x8404F5;
BANKSIZE = 0xb1;
MRSRB6 = 0x20;
MRSRB7 = 0x20;
}
int sdram_test(void)
{
volatile unsigned char *p = (volatile unsigned char *)0x30000000;
int i = 0;
//write sdram
for(i = 0; i<1000;i++ )
{
p[i] = 0x22;
}
//read sdram
for(i = 0; i<1000;i++ )
{
if(p[i] != 0x22)
{
return -1;
}
}
return 0;
}（3）uart.h
#ifndef _UART_H
#define _UART_H
#include "s3c2440_soc.h"
int uart0_init();
int putchar(int c);
int getchar(void);
int puts(char* s);
#endif
（4）uart.c
#include "s3c2440_soc.h"
/*uart初始化*/
int uart0_init()
{
/*启用txd0，rxd0*/
GPHCON &= ~((3<<6)|(3<<4));
GPHCON |= ((2<<6)|(2<<4));
/*启用内部上拉*/
GPHUP = 0;
/*设置时钟源*/
UCON0 = 0x05;
/*设置波特率115200*/
//UBRDIVn = (int)( UART clock / ( buad rate x 16) ) –1
//= (50000000/115200/16)-1
//= 26
UBRDIV0 = 26;
/*设置数据格式为 8n1*/
ULCON0 = 0x3;
}
/*输出字符*/
int putchar(int c)
{
/*检测移位寄存器是否有数据，无数据跳过，有数据则输出*/
while(!(UTRSTAT0 & (1<<2)));
/*把数据写入移位寄存器，一次可以发送一个字节*/
UTXH0 = (unsigned char)c;
return 0;
}
/*获取字符*/
int getchar(void)
{
/*检测移位寄存器是否有数据，无数据跳过，有数据则输出*/
while(!(UTRSTAT0 & (1<<0)));
/*把数据从移位寄存器读出*/
return URXH0;
}
/*输出字符串*/
int puts(char* s)
{
while(*s)
{
putchar(*s);
s++;
}
return 0;
}
(5)s3c2440_soc.h
#ifndef __S3C2440_SOC_H
#define __S3C2440_SOC_H
#define __REG(x) (*(volatile unsigned int *)(x))
#define __REG_BYTE(x) (*(volatile unsigned char*)(x))
/*Memory Controllers*/
#define BWSCON __REG(0x48000000) //Bus width & wait status control
#define BANKCON0 __REG(0x48000004) //Boot ROM control
#define BANKCON1 __REG(0x48000008) //BANK1 control
#define BANKCON2 __REG(0x4800000C) //BANK2 control
#define BANKCON3 __REG(0x48000010) //BANK3 control
#define BANKCON4 __REG(0x48000014) //BANK4 control
#define BANKCON5 __REG(0x48000018) //BANK5 control
#define BANKCON6 __REG(0x4800001C) //BANK6 control
#define BANKCON7 __REG(0x48000020) //BANK7 control
#define REFRESH __REG(0x48000024) //DRAM/SDRAM refresh control
#define BANKSIZE __REG(0x48000028) //Flexible bank size
#define MRSRB6 __REG(0x4800002C) //Mode register set for SDRAM BANK6
#define MRSRB7 __REG(0x48000030) //Mode register set for SDRAM BANK7
/*USB Host Controller*/
#define HcRevision __REG(0x49000000)
#define HcControl __REG(0x49000004)
#define HcCommonStatus __REG(0x49000008)
#define HcInterruptStatus __REG(0x4900000C)
#define HcInterruptEnable __REG(0x49000010)
#define HcInterruptDisable __REG(0x49000014)
#define HcHCCA __REG(0x49000018)
#define HcPeriodCuttentED __REG(0x4900001C)
#define HcControlHeadED __REG(0x49000020)
#define HcControlCurrentED __REG(0x49000024)
#define HcBulkHeadED __REG(0x49000028)
#define HcBulkCurrentED __REG(0x4900002C)
#define HcDoneHead __REG(0x49000030)
#define HcRmInterval __REG(0x49000034)
#define HcFmRemaining __REG(0x49000038)
#define HcFmNumber __REG(0x4900003C)
#define HcPeriodicStart __REG(0x49000040)
#define HcLSThreshold __REG(0x49000044)
#define HcRhDescriptorA __REG(0x49000048)
#define HcRhDescriptorB __REG(0x4900004C)
#define HcRhStatus __REG(0x49000050)
#define HcRhPortStatus1 __REG(0x49000054)
#define HcRhPortStatus2 __REG(0x49000058)
/*Interrupt Controller*/
#define SRCPND __REG(0X4A000000) //Interrupt request status
#define INTMOD __REG(0X4A000004) //Interrupt mode control
#define INTMSK __REG(0X4A000008) //Interrupt mask control
#define PRIORITY __REG(0X4A00000C) //IRQ priority control
#define INTPND __REG(0X4A000010) //Interrupt request status
#define INTOFFSET __REG(0X4A000014) //Interrupt request source offset
#define SUBSRCPND __REG(0X4A000018) //Sub source pending
#define INTSUBMSK __REG(0X4A00001C) //Interrupt sub mask
/*DMA*/
#define DISRC0 __REG(0x4B000000) //DMA 0 initial source
#define DISRCC0 __REG(0x4B000004) //DMA 0 initial source control
#define DIDST0 __REG(0x4B000008) //DMA 0 initial destination
#define DIDSTC0 __REG(0x4B00000C) //DMA 0 initial destination control
#define DCON0 __REG(0x4B000010) //DMA 0 control
#define DSTAT0 __REG(0x4B000014) //DMA 0 count
#define DCSRC0 __REG(0x4B000018) //DMA 0 current source
#define DCDST0 __REG(0x4B00001C) //DMA 0 current destination
#define DMASKTRIG0 __REG(0x4B000020) //DMA 0 mask trigger
#define DISRC1 __REG(0x4B000040) //DMA 1 initial source
#define DISRCC1 __REG(0x4B000044) //DMA 1 initial source control
#define DIDST1 __REG(0x4B000048) //DMA 1 initial destination
#define DIDSTC1 __REG(0x4B00004C) //DMA 1 initial destination control
#define DCON1 __REG(0x4B000050) //DMA 1 control
#define DSTAT1 __REG(0x4B000054) //DMA 1 count
#define DCSRC1 __REG(0x4B000058) //DMA 1 current source
#define DCDST1 __REG(0x4B00005C) //DMA 1 current destination
#define DMASKTRIG1 __REG(0x4B000060) //DMA 1 mask trigger
#define DISRC2 __REG(0x4B000080) //DMA 2 initial source
#define DISRCC2 __REG(0x4B000084) //DMA 2 initial source control
#define DIDST2 __REG(0x4B000088) //DMA 2 initial destination
#define DIDSTC2 __REG(0x4B00008C) //DMA 2 initial destination control
#define DCON2 __REG(0x4B000090) //DMA 2 control
#define DSTAT2 __REG(0x4B000094) //DMA 2 count
#define DCSRC2 __REG(0x4B000098) //DMA 2 current source
#define DCDST2 __REG(0x4B00009C) //DMA 2 current destination
#define DMASKTRIG2 __REG(0x4B0000A0) //DMA 2 mask trigger
#define DISRC3 __REG(0x4B0000C0) //DMA 3 initial source
#define DISRCC3 __REG(0x4B0000C4) //DMA 3 initial source control
#define DIDST3 __REG(0x4B0000C8) //DMA 3 initial destination
#define DIDSTC3 __REG(0x4B0000CC) //DMA 3 initial destination control
#define DCON3 __REG(0x4B0000D0) //DMA 3 control
#define DSTAT3 __REG(0x4B0000D4) //DMA 3 count
#define DCSRC3 __REG(0x4B0000D8) //DMA 3 current source
#define DCDST3 __REG(0x4B0000DC) //DMA 3 current destination
#define DMASKTRIG3 __REG(0x4B0000E0) //DMA 3 mask trigger
/*Clock & Power Management*/
#define LOCKTIME __REG(0x4C000000) //PLL lock time counter
#define MPLLCON __REG(0x4C000004) //MPLL control
#define UPLLCON __REG(0x4C000008) //UPLL control
#define CLKCON __REG(0x4C00000C) //Clock generator control
#define CLKSLOW __REG(0x4C000010) //Slow clock control
#define CLKDIVN __REG(0x4C000014) //Clock divider control
#define CAMDIVN __REG(0x4C000018) //Camera clock divider control
/*LCD Controller*/
#define LCDCON1 __REG(0X4D000000) //LCD control 1
#define LCDCON2 __REG(0X4D000004) //LCD control 2
#define LCDCON3 __REG(0X4D000008) //LCD control 3
#define LCDCON4 __REG(0X4D00000C) //LCD control 4
#define LCDCON5 __REG(0X4D000010) //LCD control 5
#define LCDSADDR1 __REG(0X4D000014) //STN/TFT: frame buffer start address 1
#define LCDSADDR2 __REG(0X4D000018) //STN/TFT: frame buffer start address 2
#define LCDSADDR3 __REG(0X4D00001C) //STN/TFT: virtual screen address set
#define REDLUT __REG(0X4D000020) //STN: red lookup table
#define GREENLUT __REG(0X4D000024) //STN: green lookup table
#define BLUELUT __REG(0X4D000028) //STN: blue lookup table
#define DITHMODE __REG(0X4D00004C) //STN: dithering mode
#define TPAL __REG(0X4D000050) //TFT: temporary palette
#define LCDINTPND __REG(0X4D000054) //LCD interrupt pending
#define LCDSRCPND __REG(0X4D000058) //LCD interrupt source
#define LCDINTMSK __REG(0X4D00005C) //LCD interrupt mask
#define TCONSEL __REG(0X4D000060) //TCON(LPC3600/LCC3600) control
/*NAND Flash*/
#define NFCONF __REG(0x4E000000) //NAND flash configuration
#define NFCONT __REG(0x4E000004) //NAND flash control
#define NFCMD __REG(0x4E000008) //NAND flash command
#define NFADDR __REG(0x4E00000C) //NAND flash address
#define NFDATA __REG(0x4E000010) //NAND flash data
#define NFMECC0 __REG(0x4E000014) //NAND flash main area ECC0/1
#define NFMECC1 __REG(0x4E000018) //NAND flash main area ECC2/3
#define NFSECC __REG(0x4E00001C) //NAND flash spare area ECC
#define NFSTAT __REG(0x4E000020) //NAND flash operation status
#define NFESTAT0 __REG(0x4E000024) //NAND flash ECC status for I/O[7:0]
#define NFESTAT1 __REG(0x4E000028) //NAND flash ECC status for I/O[15:8]
#define NFMECC0_STATUS __REG(0x4E00002C) //NAND flash main area ECC0 status
#define NFMECC1_STATUS __REG(0x4E000030) //NAND flash main area ECC1 status
#define NFSECC_STATUS __REG(0x4E000034) //NAND flash spare area ECC status
#define NFSBLK __REG(0x4E000038) //NAND flash start block address
#define NFEBLK __REG(0x4E00003C) //NAND flash end block address
/*Camera Interface*/
#define CISRCFMT __REG(0x4F000000) //Input source format
#define CIWDOFST __REG(0x4F000004) //Window offset register
#define CIGCTRL __REG(0x4F000008) //Global control register
#define CICOYSA1 __REG(0x4F000018) //Y 1st frame start address for codec DMA
#define CICOYSA2 __REG(0x4F00001C) //Y 2nd frame start address for codec DMA
#define CICOYSA3 __REG(0x4F000020) //Y 3nd frame start address for codec DMA
#define CICOYSA4 __REG(0x4F000024) //Y 4th frame start address for codec DMA
#define CICOCBSA1 __REG(0x4F000028) //Cb 1st frame start address for codec DMA
#define CICOCBSA2 __REG(0x4F00002C) //Cb 2nd frame start address for codec DMA
#define CICOCBSA3 __REG(0x4F000030) //Cb 3nd frame start address for codec DMA
#define CICOCBSA4 __REG(0x4F000034) //Cb 4th frame start address for codec DMA
#define CICOCRSA1 __REG(0x4F000038) //Cr 1st frame start address for codec DMA
#define CICOCRSA2 __REG(0x4F00003C) //Cr 2nd frame start address for codec DMA
#define CICOCRSA3 __REG(0x4F000040) //Cr 3nd frame start address for codec DMA
#define CICOCRSA4 __REG(0x4F000044) //Cr 4th frame start address for codec DMA
#define CICOTRGFMT __REG(0x4F000048) //Target image format of codec DMA
#define CICOCTRL __REG(0x4F00004C) //Codec DMA control related
#define CICOSCPRERATIO __REG(0x4F000050) //Codec pre-scaler ratio control
#define CICOSCPREDST __REG(0x4F000054) //Codec pre-scaler destination format
#define CICOSCCTRL __REG(0x4F000058) //Codec main-scaler control
#define CICOTAREA __REG(0x4F00005C) //Codec scaler target area
#define CICOSTATUS __REG(0x4F000064) //Codec path status
#define CIPRCLRSA1 __REG(0x4F00006C) //RGB 1st frame start address for preview DMA
#define CIPRCLRSA2 __REG(0x4F000070) //RGB 2nd frame start address for preview DMA
#define CIPRCLRSA3 __REG(0x4F000074) //RGB 3nd frame start address for preview DMA
#define CIPRCLRSA4 __REG(0x4F000078) //RGB 4th frame start address for preview DMA
#define CIPRTRGFMT __REG(0x4F00007C) //Target image format of preview DMA
#define CIPRCTRL __REG(0x4F000080) //Preview DMA control related
#define CIPRSCPRERATIO __REG(0x4F000084) //Preview pre-scaler ratio control
#define CIPRSCPREDST __REG(0x4F000088) //Preview pre-scaler destination format
#define CIPRSCCTRL __REG(0x4F00008C) //Preview main-scaler control
#define CIPRTAREA __REG(0x4F000090) //Preview scaler target area
#define CIPRSTATUS __REG(0x4F000098) //Preview path status
#define CIIMGCPT __REG(0x4F0000A0) //Image capture enable command
/*UART*/
#define ULCON0 __REG(0x50000000) //UART 0 line control
#define UCON0 __REG(0x50000004) //UART 0 control
#define UFCON0 __REG(0x50000008) //UART 0 FIFO control
#define UMCON0 __REG(0x5000000C) //UART 0 modem control
#define UTRSTAT0 __REG(0x50000010) //UART 0 Tx/Rx status
#define UERSTAT0 __REG(0x50000014) //UART 0 Rx error status
#define UFSTAT0 __REG(0x50000018) //UART 0 FIFO status
#define UMSTAT0 __REG(0x5000001C) //UART 0 modem status
#define UTXH0 __REG_BYTE(0x50000020) //UART 0 transmission hold
#define URXH0 __REG(0x50000024) //UART 0 receive buffer
#define UBRDIV0 __REG(0x50000028) //UART 0 baud rate divisor
#define ULCON1 __REG(0x50004000) //UART 1 line control
#define UCON1 __REG(0x50004004) //UART 1 control
#define UFCON1 __REG(0x50004008) //UART 1 FIFO control
#define UMCON1 __REG(0x5000400C) //UART 1 modem control
#define UTRSTAT1 __REG(0x50004010) //UART 1 Tx/Rx status
#define UERSTAT1 __REG(0x50004014) //UART 1 Rx error status
#define UFSTAT1 __REG(0x50004018) //UART 1 FIFO status
#define UMSTAT1 __REG(0x5000401C) //UART 1 modem status
#define UTXH1 __REG(0x50004020) //UART 1 transmission hold
#define URXH1 __REG(0x50004024) //UART 1 receive buffer
#define UBRDIV1 __REG(0x50004028) //UART 1 baud rate divisor
#define ULCON2 __REG(0x50008000) //UART 2 line control
#define UCON2 __REG(0x50008004) //UART 2 control
#define UFCON2 __REG(0x50008008) //UART 2 FIFO control
#define UTRSTAT2 __REG(0x50008010) //UART 2 Tx/Rx status
#define UERSTAT2 __REG(0x50008014) //UART 2 Rx error status
#define UFSTAT2 __REG(0x50008018) //UART 2 FIFO status
#define UTXH2 __REG(0x50008020) //UART 2 transmission hold
#define URXH2 __REG(0x50008024) //UART 2 receive buffer
#define UBRDIV2 __REG(0x50008028) //UART 2 baud rate divisor
/*PWM Timer*/
#define TCFG0 __REG(0x51000000) //Timer configuration
#define TCFG1 __REG(0x51000004) //Timer configuration
#define TCON __REG(0x51000008) //Timer control
#define TCNTB0 __REG(0x5100000C) //Timer count buffer 0
#define TCMPB0 __REG(0x51000010) //Timer compare buffer 0
#define TCNTO0 __REG(0x51000014) //Timer count observation 0
#define TCNTB1 __REG(0x51000018) //Timer count buffer 1
#define TCMPB1 __REG(0x5100001C) //Timer compare buffer 1
#define TCNTO1 __REG(0x51000020) //Timer count observation 1
#define TCNTB2 __REG(0x51000024) //Timer count buffer 2
#define TCMPB2 __REG(0x51000028) //Timer compare buffer 2
#define TCNTO2 __REG(0x5100002C) //Timer count observation 2
#define TCNTB3 __REG(0x51000030) //Timer count buffer 3
#define TCMPB3 __REG(0x51000034) //Timer compare buffer 3
#define TCNTO3 __REG(0x51000038) //Timer count observation 3
#define TCNTB4 __REG(0x5100003C) //Timer count buffer 4
#define TCNTO4 __REG(0x51000040) //Timer count observation 4
/*USB Device*/
#define FUNC_ADDR_REG __REG(0x52000140) //Function address
#define PWR_REG __REG(0x52000144) //Power management
#define EP_INT_REG __REG(0x52000148) //interrupt pending and clear
#define USB_INT_REG __REG(0x52000158) //USB interrupt pending and clear
#define EP_INT_EN_REG __REG(0x5200015C) //Interrupt enable
#define USB_INT_EN_REG __REG(0x5200016C) //Interrupt enable
#define FRAME_NUM1_REG __REG(0x52000170) //Frame number lower byte
#define FRAME_NUM2_REG __REG(0x52000174) //Frame number higher byte
#define INDEX_REG __REG(0x52000178) //Register index
#define EP0_CSR __REG(0x52000184) //Endpoint 0 status
#define IN_CSR1_REG __REG(0x52000184) //In endpoint control status
#define IN_CSR2_REG __REG(0x52000188) //In endpoint control status
#define MAXP_REG __REG(0x52000180) //Endpoint max packet
#define OUT_CSR1_REG __REG(0x52000190) //Out endpoint control status
#define OUT_CSR2_REG __REG(0x52000194) //Out endpoint control status
#define OUT_FIFO_CNT1_REG __REG(0x52000198) //Endpoint out write count
#define OUT_FIFO_CNT2_REG __REG(0x5200019C) //Endpoint out write count
#define EP0_FIFO __REG(0x520001C0) //Endpoint 0 FIFO
#define EP1_FIFO __REG(0x520001C4) //Endpoint 1 FIFO
#define EP2_FIFO __REG(0x520001C8) //Endpoint 2 FIFO
#define EP3_FIFO __REG(0x520001CC) //Endpoint 3 FIFO
#define EP4_FIFO __REG(0x520001D0) //Endpoint 4 FIFO
#define EP1_DMA_CON __REG(0x52000200) //EP1 DMA Interface control
#define EP1_DMA_UNIT __REG(0x52000204) //EP1 DMA Tx unit counter
#define EP1_DMA_FIFO __REG(0x52000208) //EP1 DMA Tx FIFO counter
#define EP1_DMA_TTC_L __REG(0x5200020C) //EP1 DMA Total Tx counter
#define EP1_DMA_TTC_M __REG(0x52000210) //EP1 DMA Total Tx counter
#define EP1_DMA_TTC_H __REG(0x52000214) //EP1 DMA Total Tx counter
#define EP2_DMA_CON __REG(0x52000218) //EP2 DMA interface control
#define EP2_DMA_UNIT __REG(0x5200021C) //EP2 DMA Tx Unit counter
#define EP2_DMA_FIFO __REG(0x52000220) //EP2 DMA Tx FIFO counter
#define EP2_DMA_TTC_L __REG(0x52000224) //EP2 DMA total Tx counter
#define EP2_DMA_TTC_M __REG(0x52000228) //EP2 DMA total Tx counter
#define EP2_DMA_TTC_H __REG(0x5200022C) //EP2 DMA Total Tx counter
#define EP3_DMA_CON __REG(0x52000240) //EP3 DMA Interface control
#define EP3_DMA_UNIT __REG(0x52000244) //EP3 DMA Tx Unit counter
#define EP3_DMA_FIFO __REG(0x52000248) //EP3 DMA Tx FIFO counter
#define EP3_DMA_TTC_L __REG(0x5200024C) //EP3 DMA Total Tx counter
#define EP3_DMA_TTC_M __REG(0x52000250) //EP3 DMA Total Tx counter
#define EP3_DMA_TTC_H __REG(0x52000254) //EP3 DMA Total Tx counter
#define EP4_DMA_CON __REG(0x52000258) //EP4 DMA Interface control
#define EP4_DMA_UNIT __REG(0x5200025C) //EP4 DMA Tx Unit counter
#define EP4_DMA_FIFO __REG(0x52000260) //EP4 DMA Tx FIFO counter
#define EP4_DMA_TTC_L __REG(0x52000264) //EP4 DMA Total Tx counter
#define EP4_DMA_TTC_M __REG(0x52000268) //EP4 DMA Total Tx counter
#define EP4_DMA_TTC_H __REG(0x5200026C) //EP4 DMA Total Tx counter
/* WOTCHDOG register */
#define WTCON __REG(0x53000000)
#define WTDAT __REG(0x53000004)
#define WTCNT __REG(0x53000008)
/* I2C registers */
#define IICCON __REG(0x54000000) // IIC control
#define IICSTAT __REG(0x54000004) // IIC status
#define IICADD __REG(0x54000008) // IIC address
#define IICDS __REG(0x5400000c) // IIC data shift
#define IICLC __REG(0x54000010) //IIC multi-master line control
/*IIS*/
#define IISCON __REG(0x55000000) //HW,W R/W IIS control
#define IISMOD __REG(0x55000004) //IIS mode
#define IISPSR __REG(0x55000008) //IIS prescaler
#define IISFCON __REG(0x5500000C) //IIS FIFO control
#define IISFIFO __REG(0x55000010) //HW IIS FIFO entry
/*I/O port*/
#define GPACON __REG(0x56000000) //Port A control
#define GPADAT __REG(0x56000004) //Port A data
#define GPBCON __REG(0x56000010) //Port B control
#define GPBDAT __REG(0x56000014) //Port B data
#define GPBUP __REG(0x56000018) //Pull-up control B
#define GPCCON __REG(0x56000020) //Port C control
#define GPCDAT __REG(0x56000024) //Port C data
#define GPCUP __REG(0x56000028) //Pull-up control C
#define GPDCON __REG(0x56000030) //Port D control
#define GPDDA1T __REG(0x56000034) //Port D data
#define GPDUP __REG(0x56000038) //Pull-up control D
#define GPECON __REG(0x56000040) //Port E control
#define GPEDAT __REG(0x56000044) //Port E data
#define GPEUP __REG(0x56000048) //Pull-up control E
#define GPFCON __REG(0x56000050) //Port F control
#define GPFDAT __REG(0x56000054) //Port F data
#define GPFUP __REG(0x56000058) //Pull-up control F
#define GPGCON __REG(0x56000060) //Port G control
#define GPGDAT __REG(0x56000064) //Port G data
#define GPGUP __REG(0x56000068) //Pull-up control G
#define GPHCON __REG(0x56000070) //Port H control
#define GPHDAT __REG(0x56000074) //Port H data
#define GPHUP __REG(0x56000078) //Pull-up control H
#define GPJCON __REG(0x560000D0) //Port J control
#define GPJDAT __REG(0x560000D4) //Port J data
#define GPJUP __REG(0x560000D8) //Pull-up control J
#define MISCCR __REG(0x56000080) //Miscellaneous control
#define DCLKCON __REG(0x56000084) //DCLK0/1 control
#define EXTINT0 __REG(0x56000088) //External interrupt control register 0
#define EXTINT1 __REG(0x5600008C) //External interrupt control register 1
#define EXTINT2 __REG(0x56000090) //External interrupt control register 2
#define EINTFLT0 __REG(0x56000094) //? W R/W Reserved
#define EINTFLT1 __REG(0x56000098) //Reserved
#define EINTFLT2 __REG(0x5600009C) //External interrupt filter control register 2
#define EINTFLT3 __REG(0x560000A0) //External interrupt filter control register 3
#define EINTMASK __REG(0x560000A4) //External interrupt mask
#define EINTPEND __REG(0x560000A8) //External interrupt pending
#define GSTATUS0 __REG(0x560000AC) //R External pin status
#define GSTATUS1 __REG(0x560000B0) //R/W Chip ID
#define GSTATUS2 __REG(0x560000B4) //Reset status
#define GSTATUS3 __REG(0x560000B8) //Inform register
#define GSTATUS4 __REG(0x560000BC) //Inform register
#define MSLCON __REG(0x560000CC) //Memory sleep control register
/*RTC*/
#define RTCCON __REG(0x57000040) //RTC control
#define TICNT __REG(0x57000044) //Tick time count
#define RTCALM __REG(0x57000050) //RTC alarm control
#define ALMSEC __REG(0x57000054) //Alarm second
#define ALMMIN __REG(0x57000058) //Alarm minute
#define ALMHOUR __REG(0x5700005C) //Alarm hour
#define ALMDATE __REG(0x57000060) //alarm day
#define ALMMON __REG(0x57000064) //Alarm month
#define ALMYEAR __REG(0x57000068) //Alarm year
#define BCDSEC __REG(0x57000070) //BCD second
#define BCDMIN __REG(0x57000074) //BCD minute
#define BCDHOUR __REG(0x57000078) //BCD hour
#define BCDDATE __REG(0x5700007C) //BCD day
#define BCDDAY __REG(0x57000080) //BCD date
#define BCDMON __REG(0x57000084) //BCD month
#define BCDYEAR __REG(0x57000088) //BCD year
/*A/D Converte*/
#define ADCCON __REG(0x58000000) //ADC control
#define ADCTSC __REG(0x58000004) //ADC touch screen control
#define ADCDLY __REG(0x58000008) //ADC start or interval delay
#define ADCDAT0 __REG(0x5800000C) //ADC conversion data
#define ADCDAT1 __REG(0x58000010) //ADC conversion data
#define ADCUPDN __REG(0x58000014) //Stylus up or down interrupt status
/*SPI CONTROL REGISTER*/
#define SPCON0 __REG(0x59000000) //SPI channel 0 control register
#define SPSTA0 __REG(0x59000004) //SPI channel 0 status register
#define SPPIN0 __REG(0x59000008) //SPI channel 0 pin control register
#define SPPRE0 __REG(0x5900000C) //SPI cannel 0 baud rate prescaler register
#define SPTDAT0 __REG(0x59000010) //SPI channel 0 Tx data register
#define SPRDAT0 __REG(0x59000014) //SPI channel 0 Rx data register
#define SPCON1 __REG(0x59000020) //SPI channel 1 control register
#define SPSTA1 __REG(0x59000024) //SPI channel 1 status register
#define SPPIN1 __REG(0x59000028) // SPI channel 1 pin control register
#define SPPRE1 __REG(0x5900002C) //SPI cannel 1 baud rate prescaler register
#define SPTDAT1 __REG(0x59000030) //SPI channel 1 Tx data register
#define SPRDAT1 __REG(0x59000034) //SPI channel 1 Rx data register
/*SD Interface*/
#define SDICON __REG(0x5A000000) //SDI control
#define SDIPRE __REG(0x5A000004) //SDI baud rate prescaler
#define SDICARG __REG(0x5A000008) //SDI command argument
#define SDICCON __REG(0x5A00000C) //SDI command control
#define SDICSTA __REG(0x5A000010) //SDI command status
#define SDIRSP0 __REG(0x5A000014) //SDI response
#define SDIRSP1 __REG(0x5A000018) //SDI response
#define SDIRSP2 __REG(0x5A00001C) //SDI response
#define SDIRSP3 __REG(0x5A000020) //SDI response
#define SDIDTIMER __REG(0x5A000024) //SDI data / busy timer
#define SDIBSIZE __REG(0x5A000028) //SDI block size
#define SDIDCON __REG(0x5A00002C) //SDI data control
#define SDIDCNT __REG(0x5A000030) //SDI data remain counter
#define SDIDSTA __REG(0x5A000034) //SDI data status
#define SDIFSTA __REG(0x5A000038) //SDI FIFO status
#define SDIIMSK __REG(0x5A00003C) //SDI interrupt mask
#define SDIDAT __REG(0x5A000040) //SDI data
#endif
(6)main.c
#include "sdram.h"
#include "s3c2440_soc.h"
#include "uart.h"
char g_char = 'A;
int main()
{
uart0_init();
while(1)
{
putchar(g_char);
g_char++;/*nor启动时此代码无效*/
delay(100000);
}
return 0;
}
(7)启动代码start.S
.text
.global _start
_start:
/* 关闭看门狗 */
ldr r0, =0x53000000
ldr r1, =0
str r1, [r0]
/* 设置MPLL, FCLK : HCLK : PCLK = 400m : 100m : 50m */
/* LOCKTIME(0x4C000000) = 0xFFFFFFFF */
ldr r0, =0x4C000000
ldr r1, =0xFFFFFFFF
str r1, [r0]
/* CLKDIVN(0x4C000014) = 0X5, tFCLK:tHCLK:tPCLK = 1:4:8 */
ldr r0, =0x4C000014
ldr r1, =0x5
str r1, [r0]
/* 设置CPU工作于异步模式 */
mrc p15,0,r0,c1,c0,0
orr r0,r0,#0xc0000000 //R1_nF:OR:R1_iA
mcr p15,0,r0,c1,c0,0
/* 设置MPLLCON(0x4C000004) = (92<<12)|(1<<4)|(1<<0)
* m = MDIV+8 = 92+8=100
* p = PDIV+2 = 1+2 = 3
* s = SDIV = 1
* FCLK = 2*m*Fin/(p*2^s) = 2*100*12/(3*2^1)=400M
*/
ldr r0, =0x4C000004
ldr r1, =(92<<12)|(1<<4)|(1<<0)
str r1, [r0]
/* 一旦设置PLL, 就会锁定lock time直到PLL输出稳定
* 然后CPU工作于新的频率FCLK
*/
/* 设置内存: sp 栈 */
/* 分辨是nor/nand启动
* 写0到0地址, 再读出来
* 如果得到0, 表示0地址上的内容被修改了, 它对应ram, 这就是nand启动
* 否则就是nor启动
*/
mov r1, #0
ldr r0, [r1] /* 读出原来的值备份 */
str r1, [r1] /* 0->[0] */
ldr r2, [r1] /* r2=[0] */
cmp r1, r2 /* r1==r2? 如果相等表示是NAND启动 */
ldr sp, =0x40000000+4096 /* 先假设是nor启动 */
moveq sp, #4096 /* nand启动 */
streq r0, [r1] /* 恢复原来的值 */
bl main
halt:
b halt
(8)Makefile
all:
arm-linux-gcc -c -o led.o led.c
arm-linux-gcc -c -o uart.o uart.c
arm-linux-gcc -c -o sdram.o sdram.c
arm-linux-gcc -c -o main.o main.c
arm-linux-gcc -c -o start.o start.S
arm-linux-ld -Ttext 0 start.o led.o uart.o sdram.o main.o -o sdram.elf
arm-linux-objcopy -O binary -S sdram.elf sdram.bin
arm-linux-objdump -D sdram.elf > sdram.dis
clean:
rm *.bin *.o *.elf *.dis
把程序上传到linux平台编译编译后我们会发现sdram.bin为什么会这么大，我们打开sdram.dis查看一下反汇编代码
我们会发现数据段的起始地址是8478，这样会让程序便的很大我们修改Makefile
Makefile
-Tdata 0x800指定数据段的地址为0x800
all:
arm-linux-gcc -c -o led.o led.c
arm-linux-gcc -c -o uart.o uart.c
arm-linux-gcc -c -o sdram.o sdram.c
arm-linux-gcc -c -o main.o main.c
arm-linux-gcc -c -o start.o start.S
arm-linux-ld -Ttext 0 -Tdata 0x800 start.o led.o uart.o sdram.o main.o -o sdram.elf
arm-linux-objcopy -O binary -S sdram.elf sdram.bin
arm-linux-objdump -D sdram.elf > sdram.dis
clean:
rm *.bin *.o *.elf *.dis
上传后重新make，发现bin文件小了很多
我们把bin文件烧入nor和nand中
在nor中发现
字符是不变的在nand中字符是变化的因为g_char++;/*nor启动时此代码无效*/
3.段的引入
从上述代码我们可以看出程序最少包含数据段和代码段
数据段：存放全局变量
我们看看是否含有其他的段，修改main.c
#include "sdram.h"
#include "s3c2440_soc.h"
#include "uart.h"
char g_char = 'A';
const char g_char2 = 'B';
int g_A = 0;
int g_B;
int main()
{
uart0_init();
while(1)
{
putchar(g_char);
g_char++;/*nor启动时此代码无效*/
delay(100000);
}
return 0;
}
重新上传编译，查看返回编码
发现除了data段和text段还有bss段、只读数据段（rodata）、comment段（注释段）
data段存放有初值但不为0的全局变量
rodata存放固定值的全局变量
bss段存放初值为0和没有初值的全局变量
comment存放一些注释包含编译器信息
ls -al查看bin文件大小为2049，也就是0x801字节，但是我们查看返回编码发现bss段的起始地址为0x804，所以说bss段和comment段并不保存在bin文件中，因为初值为0或没有初值的全局变量我们没必要保存，对于注释而言就更没有必要了
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