Samsung MUXONENAND A-DIE KFM2G16Q2A - Manual (Page 127)

MuxOneNAND2G(KFM2G16Q2A-DEBx)
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FLASH MEMORY
MuxOneNAND4G(KFN4G16Q2A-DEBx)
3.14.4 1st Block OTP Lock Operation
1st Block could be used as OTP, for secured booting operation.
1st Block OTP can be accessed just as any other NAND Flash Array Blocks before it is locked, however, once 1st Block is locked to be OTP,
1st Block OTP cannot be erased or programmed.
Note that OTP Block can be locked freely after locking 1st Block OTP.
Locking the 1st Block OTP
Programming to the 1st Block OTP area can be prevented by locking the OTP area. Locking the OTP area is accomplished by programming
XXF3h to 8th word of sector0 in page0 spare area in the OTP block.
At device power-up, this word location is checked and if XXF3h is found, the OTP
BL
bit of the Controller Status Register is set to "1", indicating
the 1st Block is locked. When the Program Operation finds that the status of the 1st Block is locked, the device updates the Error Bit of the
Controller Status Register as "1" (fail).
1st Block 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).
• Write 'XXF3h' 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 1st Block OTP lock is complete, do a Cold Reset to exit the OTP Access mode and update 1st Block OTP lock bit[5].
• 1st Block OTP lock bit[5] of the Controller Status Register will be set to "1" and the 1st Block will be locked.
Even though the OTP area can only be programmed once without erase capability, it can be locked when the device starts up to prevent any
changes from being made.
Unlike other remaining main area of the NAND Flash Array memory, once the 1st block OTP is locked, it cannot be unlocked.