sst29sf040不是flash吗,为什么我把它当作数据存储器时一掉电数据就会丢失呢？
sst29sf040的A0-A7接74ls373的输出，74373集成在CPLD中，没画出来,A8-A14接AT89C52的P20-P26，而A15-A18接地，因为我用不到那么大的空间，而其片选端CE接AT89C52的P27
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();我 在程序中改变syn 的值未写出，为什么我一断电，syn 的值还是原来的赋的初值呢？
} |
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