EMBEDDED FLASH MEMORY INTERFACE S3F8275X
16-12

HARD LOCK PROTECTION

User can set Hard Lock Protection by write ‘0110’ in FMCON.7−4. If this function is enabled, the user cannot write
or erase the data in a flash memory area. This protection can be released by the chip erase execution (in the tool
program mode).
In terms of user program mode, the procedure of setting Hard Lock Protection is following that. Whereas in tool
mode the manufacturer of serial tool writer could support Hardware Protection. Please refer to the manual of serial
program writer tool provided by the manufacturer.
The Hard Lock Protection Procedure in User program Mode
1. Set Flash Memory User Programming Enable Register (FMUSR) to “10100101B”.
2. Check user’s ID code (written by user)
3. Set Flash Memory Control Register (FMCON) to “01100001B”.
4. Set Flash Memory User Programming Enable Register (FMUSR) to “00000000B”.
PROGRAMMING TIP ⎯ Hard Lock Protection
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SB1
LD FMUSR,#0A5H ; User Program mode enable
CP UserID_Code,#User_value ; Check user’s ID code (written by user)
; User_value is any value by user
JR NE,Not_ID_Code ; If not equal, jump to Not_ID_Code
LD FMCON,#01100001B ; Hard Lock mode set & start
NOP ; Dummy Instruction, This instruction must be needed
LD FMUSR,#0 ; User Program mode disable
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Not_ID_Code: SB1
LD FMUSR,#0 ; User Program mode disable
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