接口設計：

對SDRAM初始化

對內存控制器初始化

memsetup:
mov r1,#MEM_CTL_BASE
adrl r2,mem_cfg_val
add r3,r1,#52
ldr r4,[r2],#4

str r4,[r1],#4

cmp r1,r3

bne 1b

mov pc,lr

復制代碼到SDRAM,將SRAM中的4K數(shù)據(jù)全部復制到SDRAM，
SRAM起始地址為0x00000000，SDRAM的起始地址為0x30000000
copy_steppingstone_to_sdram:
mov r1,#0

ldr r2,=SDRAM_BASE

mov r3 ,#4*1024

ldr r4,[r1],#4

str r4,[r2],#4

cmp r1,r3

bne 1b

mov pc,lr
align 4

存儲控制器13個寄存器的設置值
mem_cfg_val:long 0x22011110

BWSCON：long 0x00000000

BANKCON0 long 0x00000700

BANKCON1 long 0x00000700

BANKCON2 long 0x00000700

BANKCON3 long 0x00000700

BANKCON4 long 0x00000700

BANKCON5 long 0x00000700

BANKCON6 long 0x00018005

BANKCON7 long 0x00018005

REFRESHlong 0x008e07a3

BANKSIZE long 0x000000b2

MRSRB6 long 0x00000030、

MRSRB7 long 0x00000030

NAND FLASH配置寄存器初始化

MemCfgInit();//設置NAND FLASH的配置寄存器

void MemCfgInit(void)
{
//rCLKCON |= 0xffff0;
//enable nand flash control, initilize ecc, chip disable,
rNFCONF = (1<<15)|(1<<12)|(1<<11)|(7<<8)|(7<<4)|(7);
}