DSP6713在CE1空间接了一个Flash，CE1#片选信号都不拉低的原因是什么？

您好，我用的是DSP6713，在CE1空间接了一个Flash：AM29LV160D，但不知道为什么不论擦除，还是读写，CE1#片选信号都不拉低，请问哪些原因会导致这个问题？谢谢您的回答。
下面是我的程序：
主程序：
Flash_StartAdd = 0x90000000;

flash_chip_erase();
printf("Finish flash erase!!n");
// Write flash memory.
for(i=0;i<0x400;i++)
[
data = i;//fmod(i,0x10000);
addr = (Flash_StartAdd+2*i);
Write_Flash_Word(&data,&addr);
]
printf("Write flash ok.n");
// Read flash memory.
for(i=0;i<0x400;i++)
[
addr = Flash_StartAdd+2*i;
Read_Flash_Word(&data,&addr);
if(data != fmod(i,0x10000))
[
printf(" Testing is Failure!n");
printf("Address 0x%x is error! Data is 0x%xn",i,data);
exit(0);
]
]
printf("Opereation is success.n");
相关函数：
#define FLASH_ADR1 (0x90000000+0x555<<1)
#define FLASH_ADR2 (0x90000000+0x2AA<<1)
#define Sourceaddr 0x90000000
#define Toggle_Bit 0x80 //0x40 /* d6 = 1 */
#define Hangup_Bit 0x20 /* d5 = 1 */
#define Pass_Flag 0
#define Fail_Flag 1
void flash_chip_erase()
[
*(volatile Uint16*)FLASH_ADR1=0x012a;//0xaa;
*(volatile Uint16*)FLASH_ADR2=0x0095;//0x55;
*(volatile Uint16*)FLASH_ADR1=0x0100;//0x80;
*(volatile Uint16*)FLASH_ADR1=0x012a;//0xaa;
*(volatile Uint16*)FLASH_ADR2=0x0095;//0x55;
*(volatile Uint16*)FLASH_ADR1=0x0010;//0x10;
]
int Toggle_Bit_Check(Uint16 *addr)
[
Uint16 toggle_data,read_data;
toggle_data = *addr&Toggle_Bit;
do[
if(((read_data = *addr) &Toggle_Bit) == toggle_data)
break;
toggle_data = read_data & Toggle_Bit;
]while((read_data&Hangup_Bit) != Hangup_Bit);
toggle_data = *addr & Toggle_Bit;
if(((read_data = *addr)&Toggle_Bit) != toggle_data)
return (Fail_Flag);
return (Pass_Flag);
]

int Write_Flash_Word(Uint16 *data,Uint16 *address)
[
*(volatile Uint16 *)FLASH_ADR1=0x012a;//0xaa;
*(volatile Uint16 *)FLASH_ADR2=0x0095;//0x55;
*(volatile Uint16 *)FLASH_ADR1=0x0120;//0xa0;
*address=*data;
return(Toggle_Bit_Check(address));
]
int Read_Flash_Word(Uint16 *data,Uint16 *address)
[
*(volatile Uint16 *)FLASH_ADR1=0x012a;//0xaa;
*(volatile Uint16 *)FLASH_ADR2=0x0095;//0x55;
*(volatile Uint16 *)FLASH_ADR1=0x01b0;//0xf0;
*data=*address;
return(Toggle_Bit_Check(address));
]