UPD78F1502AGK-GAK-AX Datasheet, PDF (859/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 27 FLASH MEMORY
27.7 Security Settings
The 78K0R/Lx3 microcontrollers support a security function that prohibits rewriting the user program written to the
internal flash memory, so that the program cannot be changed by an unauthorized person.
The operations shown below can be performed using the Security Set command. The security setting is valid when the
programming mode is set next.
• Disabling batch erase (chip erase)
Execution of the block erase and batch erase (chip erase) commands for entire blocks in the flash memory is
prohibited by this setting during on-board/off-board programming. Once execution of the batch erase (chip erase)
command is prohibited, all of the prohibition settings (including prohibition of batch erase (chip erase)) can no longer
be cancelled.
Caution After the security setting for 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.
• Disabling block erase
Execution of the block erase command for a specific block in the flash memory is prohibited during on-board/off-board
programming. However, blocks can be erased by means of self programming.
• Disabling write
Execution of the write and block erase commands for entire blocks in the flash memory is prohibited during on-
board/off-board programming. However, blocks can be written by means of self programming.
• Disabling rewriting boot cluster 0
Execution of the batch erase (chip erase) command, block erase command, and write command on boot cluster 0
(00000H to 00FFFH) in the flash memory is prohibited by this setting.
Caution If a security setting that rewrites boot cluster 0 has been applied, boot cluster 0 of that device will
not be rewritten, and the entire flash memory of the device will not be erased in batch.
The batch erase (chip erase), block erase, write commands, and rewriting boot cluster 0 are enabled by the default
setting when the flash memory is shipped. Security can be set by on-board/off-board programming and self programming.
Each security setting can be used in combination.
All the security settings are cleared by executing the batch erase (chip erase) command.
Table 27-6 shows the relationship between the erase and write commands when the 78K0R/Lx3 microcontrollers
security function is enabled.
Remark To prohibit writing and erasing during self-programming, use the flash sealed window function (see 27.8.2 for
detail).
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Jun 20, 2011