Security Settings - NEC 78K0S/KB1+ User Manual
8-bit single-chip microcontrollers
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Also See for 78K0S/KB1+:
- Application note (49 pages) ,
- Application note (37 pages) ,
- Application note (38 pages)
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ACK
NAK
19.7.3 Security settings
The operations shown below can be prohibited using the security setting command.
• Batch erase (chip erase) is prohibited
Execution of the block erase and batch erase (chip erase) commands for entire blocks in the flash memory is
prohibited. Once execution of the batch erase (chip erase) command is prohibited, all the prohibition settings can
no longer be cancelled.
Caution After the security setting of the batch erase is set, erasure cannot be performed for the device.
In addition, even if a write command is executed, data different from that which has already
been written to the flash memory cannot be written because the erase command is disabled.
• Block erase is prohibited
Execution of the block erase command in the flash memory is prohibited. This prohibition setting can be
cancelled using the batch erase (chip erase) command.
• Write is prohibited
Execution of the write and block erase commands for entire blocks in the flash memory is prohibited. This
prohibition setting can be cancelled using the batch erase (chip erase) command.
Remark
The security setting is valid when the programming mode is set next time.
The batch erase (chip erase), block erase, and write commands are enabled by the default setting when the flash
memory is shipped. The above security settings are possible only for on-board/off-board programming. Each security
setting can be used in combination.
Table 19-8 shows the relationship between the erase and write commands when the 78K0S/KB1+ security function
is enabled.
Table 19-8. Relationship Between Commands When Security Function Is Enabled
Security
When batch erase (chip erase) security
operation is enabled
When block erase security operation is
enabled
When write security operation is enabled
Note Since the erase command is disabled, data different from that which has already been written to the
flash memory cannot be written.
CHAPTER 19 FLASH MEMORY
Table 19-7. Response Name
Response Name
Command
Batch Erase (Chip
Erase) Command
Disabled
Enabled
User's Manual U17446EJ3V1UD
Function
Acknowledges command/data.
Acknowledges illegal command/data.
Block Erase
Command
Disabled
Write Command
Note
Enabled
Enabled
Disabled
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