在开发板运行uClinux后,我这样擦除Flash怎不成功?

#define AM_ADDR_UNLOCK1        0x555
#define AM_ADDR_UNLOCK2        0x2aa
#define AM_DATA_UNLOCK1        0xaaaa
#define AM_DATA_UNLOCK2        0x5555
#define AM_SETUP_WRITE         0xa0a0
#define AM_SETUP_ERASE         0x8080
#define AM_CHIP_ERASE          0x1010
#define AM_SECTOR_ERASE        0x3030
#define AM_START_ADDR 0x02000000    /*因运行uClinux时Flash
地址被映射到0x02000000*/

int earaFlash()
{        
    printf("Start easraFlash!\n");
    *((volatile UINT16 *)AM_START_ADDR+ AM_ADDR_UNLOCK1) = AM_DATA_UNLOCK1;
    *((volatile UINT16 *)AM_START_ADDR+ AM_ADDR_UNLOCK2) = AM_DATA_UNLOCK2;
    *((volatile UINT16 *)AM_START_ADDR+ AM_ADDR_UNLOCK1) = AM_SETUP_ERASE;         
    *((volatile UINT16 *)AM_START_ADDR+ AM_ADDR_UNLOCK1) = AM_DATA_UNLOCK1;       
    *((volatile UINT16 *)AM_START_ADDR+ AM_ADDR_UNLOCK2) = AM_DATA_UNLOCK2;  
    *((volatile UINT16 *)AM_START_ADDR+ AM_ADDR_UNLOCK1) = AM_CHIP_ERASE;
    printf("End easraFlash!\n");
    return(0); 
}