OneNAND512Mb(KFG1216U2B-xIB6)
3.11.3 OTP Block Lock Operation
FLASH MEMORY
Even though the OTP area can only be programmed once without erase capability, it can be locked when the device starts up to pre-
vent any changes from being made.
Unlike the main area of the NAND Flash Array memory, once the OTP block is locked, it cannot be unlocked, for locking bit for
both blocks lies in the same word of OTP area.
Therefore, if OTP Block is locked prior to 1st Block OTP lock, 1st Block OTP cannot be locked.
Locking the OTP
Programming to the OTP area can be prevented by locking the OTP area. Locking the OTP area is accomplished by
programming XXFCh to 8th word of sector0 in page0 spare area in the OTP block.
At device power-up, this word location is checked and if XXFCh is found, the OTPL bit of the Controller Status Register is set to "1",
indicating the OTP is locked. When the Program Operation finds that the status of the OTP is locked, the device updates the Error Bit
of the Controller Status Register as "1" (fail).
OTP Lock Operation Steps
•
Issue the OTP Access Command
• Fill data to be programmed into DataRAM (data can be input at anytime between the "Start" and "Write Program" commands)
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•
•
•
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Write 'XXFCh' data into the 8th word of sector0 in page0 spare area of the DataRAM.
Issue a Flash Block Address (FBA) which is unlocked area address of NAND Flash Array address map.
Issue a Program command to program the data from the DataRAM into the OTP
When the OTP lock is complete, do a Cold Reset to exit the OTP Access mode and update OTP lock bit[6].
OTP lock bit[6] of the Controller Status Register will be set to "1" and the OTP will be locked.
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