Samsung FLEX-MUXONENAND KFN8GH6Q4M - Manual (Page 62)

Flex-MuxOneNAND4G(KFM4GH6Q4M-DEBx)
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FLASH MEMORY
Flex-MuxOneNAND8G(KFN8GH6Q4M-DEBx)
Flex-MuxOneNAND16G(KFKAGH6Q4M-DEBx)
3.4.3.3 Locked-tight NAND Array Write Protection State
A block that is in a locked-tight state can only be changed to locked state after a Cold or Warm Reset. Unlock and Lock command sequences
will not affect its state. This is an added level of write protection security.
A block must first be set to a locked state before it can be changed to locked-tight using the Lock-tight command. locked-tight blocks will revert
to a locked state following a Cold or Warm Reset.
When there are Lock-tight blocks in the flash array, All Block Unlock Command will fail and there will be no change in the lock status of the
blocks of the Flash array.
Thus, All Block Unlock command succeeds only when there are no tightly-locked blocks in Flash.
3.4.4 NAND Flash Array Write Protection State Diagram
* NOTE : If the 1st Block is set to be OTP, Block 0 will always be Lock Status
Lock-Tight Command Sequence:
Start block address+Lock-tight block command (002Ch)
Locked-tight
Power On
Start block address
+Unlock block Command
RP pin: High
&
Lock block Command
RP pin: High
&
+Lock-tight block Command
RP pin: High
&
Cold reset or
unlock
Lock
Lock-tight
Lock
Lock
Warm reset
Start block address
Lock
Lock
Start block address
Cold reset or
Warm reset
or
unlock
Start block address (000h)
RP pin: High
&
+All Block Unlock Command