User’s Manual U17029EJ3V0UM
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APPENDIX A ON-CHIP FLASH MEMORY SECURITY FUNCTIONS
Microcontrollers that include flash memory include an authentication function that reads an embedded 10-byte ID
code as a security measure against unauthorized access to flash memory.
This ID code’s specifications are described below. Be sure to write the ID code to on-chip flash memory according
to these specifications. Also, when using the integrated debugger with the QB-78K0MINI to start debugging (i.e.,
when reading the target device’s on-chip flash memory code), enter the ID code in the integrated debugger’s
configuration screen and perform ID code authentication.
[ID code specifications]
•
The values of addresses 0x85 to 0x8E comprise the 10-byte ID code.
•
Bits 0 and 1 at address 0x84 are the use enable flag bits for the QB-78K0MINI (“00b” = use prohibited, any
other value = use enabled).
•
If the ID code input to the integrated debugger matches the ID code embedded in the on-chip flash memory,
debugging can be performed.
•
Even if these two ID codes match, debugging cannot be performed when the QB-78K0MINI use enable flag
value is “00b”.
•
When flash memory contents are erased, its ID code becomes 0xFFFFFFFFFFFFFFFFFFFF.
Caution Of “00” is written to address 0x84, write operations from the QB-78K0MINI become disabled, and
only write operations from a flash programmer are enabled.
The following is an ID code setting example.
(Example) When the following values are set to addresses 0x85 to 0x8E
Address Value
[7:0]
0x85 0x12
0x86 0x34
0x87 0x56
0x88 0x78
0x89 0x9A
0x8A 0xBC
0x8B 0xDE
0x8C 0xF1
0x8D 0x23
0x8E 0xD4
The ID code to be input via the integrated debugger ID78K0-QB’s configuration dialog box is either
123456789ABCDEF123D4 or 123456789abcdef123d4.
Assembler code
cseg secur_id
db 12h
db 34h
db 56h
db 78h
db 9ah
db 0bch
db 0deh
db 0f1h
db 23h
db 0d4h
