UPD78F0838 Renesas Electronics Corporation., UPD78F0838 Datasheet - Page 821

• Manufacturer Part Number: UPD78F0838
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

26.8 Security Settings
memory, so that the program cannot be changed by an unauthorized person.
the programming mode is set next.
setting when the flash memory is shipped.
programming. Each security setting can be used in combination.
is enabled.
The 78K0/Dx2 supports a security function that prohibits rewriting the user program written to the internal flash
The operations shown below can be performed using the security set command. The security setting is valid when
The batch erase (chip erase), block erase, write commands, and rewriting boot cluster 0 are enabled by the default
Prohibition of erasing blocks and writing is cleared by executing the batch erase (chip erase) command.
Table 26-10 shows the relationship between the erase and write commands when the 78K0/Dx2 security function
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.
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 (0000H to 0FFFH) 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
Caution After the security setting for the batch erase is set, erasure cannot be performed for the device.
will not be rewritten.
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.
Preliminary User’s Manual U19748EJ1V0UD
CHAPTER 26 FLASH MEMORY
Security can be set by on-board/off-board programming and self
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