CHAPTER 4 HOW TO USE MINICUBE2 WITH 78K0 MICROCONTROLLER
User’s Manual U18371EJ1V0UM
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(b) Option byte area (essential)
This is the area for the security setting to prevent the flash memory from being read by an unauthorized person.
The target device operates in accordance with the set value, as shown below.
Table 4-8. Option Byte Setting and Operation
Set Value
Description
Remark
0x00
Debugging is unavailable even if an on-chip debug emulator
(such as MINICUBE2) is connected.
This setting is available
only for flash programming.
0x02
The on-chip flash memory is not erased no matter how many
times the security ID code authentication fails.
-
0x03
All on-chip flash memory areas are erased if the security ID
code authentication fails.
-
Other than above
Setting prohibited
-
[How to set]
Describe the code for setting the option byte in the user program. Refer to the following and add a code to
the assembler source.
Example
When setting 0x02
SSS
CSEG
AT
084H;
″
SSS
″
is an arbitrary symbol name (eight characters or less)
DB
2H
Caution If address 0x84 is overwritten by 0x00 by self programming, communication is disabled, and
debugging and connection can no longer be performed even if the debugger is restarted. In
such as case, erase the memory via flash programming.
(c) Security ID area (essential)
This is the area for the security setting to prevent the flash memory from being read by an unauthorized person.
The security ID functions as a password for starting the debugger. The debugger starts only when the
security ID that is input during debugger startup and the security ID embedded in this area match.
[How to set]
When using NEC Electronics assembler RA78K0, an ID code is generated in this area, using the linker option
(-gi). Figure 4-31 shows the Linker Options dialog box of the project manager. Select the
″
Security ID
″
check box as shown in the figure below and set an arbitrary ID code (10 bytes).
