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3387L–DFLASH–6/06

AT45DB321C

6.3.4

Various Aspects About the Sector Protection Register

Due to the sharing of the internal circuitry, the contents of the buffer 1 will get modified during the

erase and programming of Sector Protection Register. If the device is powered down during

erasing or programming the sector protection register, then the contents of the Sector Protection

Register cannot be guaranteed. The Sector Protection Register can be erased or reprogrammed

with the sector protection enabled or disabled. Being able to reprogram the Sector Protection

Register with the sector protection enabled allows the user to temporarily disable the sector pro-

tection to an individual sector rather than disabling the sector protection completely.

The Sector Protection Register is subject to the same endurance characteristics as the main

memory array. Users are encouraged to carefully evaluate the number of times the Sector Pro-

tection Register will be modified during the course of the applications’ life cycle. If the application

requires that the Sector Protection Register be modified more than the specified endurance of

the DataFlash because the application needs to temporarily unprotect individual sectors (sector

protection remains enabled while the Sector Protection Register is reprogrammed), then the

application will need to limit this practice. Instead, a combination of temporarily unprotecting indi-

vidual sectors along with disabling sector protection completely will need to be implemented by

the application to ensure that the endurance limits of the device are not exceeded.