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| sst29sf040作为数据存储器时，为何掉电后数据恢复为初始化的值呢 |
| 新闻出处：21ic
发布时间： 2007-09-25 |
ccjchen 发布于 2007-9-25 8:43:00
sst29sf040不是flash吗，难道数据会丢失吗？我仿真时看到数据也写进了sst29sf040阿，为什么一烧写进芯片后掉电数据就会恢复为初始化的值呢？
下面是我改变数组 syn 的值并存储到sst29sf040的程序
void ByteProgram(uchar data SrcByte,uint Dst)
{
XBYTE[0x0555] = 0xAA;
XBYTE[0x02AA] = 0x55;
XBYTE[0x0555] = 0xA0;
XBYTE[Dst] = SrcByte;
wait(1,9);//等待25us
}
int Erase_One_Sector(uint Dst)
{
/* Issue the Sector Erase command to 39SF040 */
XBYTE[0x0555] = 0xAA; /* set up address to be 555h */
/* write data 0xAA to the address */
XBYTE[0x02AA] = 0x55; /* set up address to be 2AAh */
/* write data 0x55 to the address */
XBYTE[0x0555] = 0x80; /* set up address to be 555h */
/* write data 0x80 to the address */
XBYTE[0x0555] = 0xAA; /* set up address to be 555h */
/* write data 0xAA to the address */
XBYTE[0x02AA] = 0x55; /* set up address to be 2AAh */
/* write data 0x55 to the address */
XBYTE[Dst] = 0x20; /* set up starting address to be erased */
/* write data 0x30 to the address */
wait(85,134); /* check DATABOOK for the most */
/* accurate value -- Tse */
}
uchar ByteRead(uint addr)
{
uchar GetData;
GetData = XBYTE[addr];
return(GetData);
}
void sst_save()//用于保存易丢失数据
{
uchar i;
Erase_One_Sector(128);
for(i=0;i<4;i++)
{
ByteProgram(syn[2*i+1],0x0080+i);
syn[2*i+1]=ByteRead(0x0080+i);
}
}
void main()
{
sst_save();
}
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