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AT45DB041D-SU-SL954 参数 Datasheet PDF下载

AT45DB041D-SU-SL954图片预览
型号: AT45DB041D-SU-SL954
PDF下载: 下载PDF文件 查看货源
内容描述: 4兆位2.5伏或2.7伏的DataFlash [4-megabit 2.5-volt or 2.7-volt DataFlash]
分类和应用: 闪存存储内存集成电路光电二极管异步传输模式ATM时钟
文件页数/大小: 53 页 / 1649 K
品牌: ATMEL [ ATMEL ]
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AT45DB041D  
9.1.1  
Erase Sector Protection Register Command  
In order to modify and change the values of the Sector Protection Register, it must first be  
erased using the Erase Sector Protection Register command.  
To erase the Sector Protection Register, the CS pin must first be asserted as it would be with  
any other command. Once the CS pin has been asserted, the appropriate 4-byte opcode  
sequence must be clocked into the device via the SI pin. The 4-byte opcode sequence must  
start with 3DH and be followed by 2AH, 7FH, and CFH. After the last bit of the opcode sequence  
has been clocked in, the CS pin must be deasserted to initiate the internally self-timed erase  
cycle. The erasing of the Sector Protection Register should take place in a time of tPE, during  
which time the Status Register will indicate that the device is busy. If the device is powered-  
down before the completion of the erase cycle, then the contents of the Sector Protection Regis-  
ter cannot be guaranteed.  
The Sector Protection Register can be erased with the sector protection enabled or disabled.  
Since the erased state (FFH) of each byte in the Sector Protection Register is used to indicate  
that a sector is specified for protection, leaving the sector protection enabled during the erasing  
of the register allows the protection scheme to be more effective in the prevention of accidental  
programming or erasing of the device. If for some reason an erroneous program or erase com-  
mand is sent to the device immediately after erasing the Sector Protection Register and before  
the register can be reprogrammed, then the erroneous program or erase command will not be  
processed because all sectors would be protected.  
Command  
Byte 1  
Byte 2  
Byte 3  
Byte 4  
Erase Sector Protection Register  
3DH  
2AH  
7FH  
CFH  
Figure 9-2. Erase Sector Protection Register  
CS  
Opcode  
Byte 1  
Opcode  
Byte 2  
Opcode  
Byte 3  
Opcode  
Byte 4  
SI  
Each transition  
represents 8 bits  
15  
3595L–DFLASH–4/08