Renesas RL78 Series User Manual page 802

RL78/G1D
26.6.3 Flash shield window function
The flash shield window function is provided as one of the security functions for self-programming. It disables writing to
and erasing areas outside the range specified as a window only during self-programming.
The window range can be set by specifying the start and end blocks. The window range can be set or changed during
both serial programming and self-programming.
Writing to and erasing areas outside the window range are disabled during self-programming. During serial
programming, however, areas outside the range specified as a window can be written and erased.
Window range
Flash memory
area
Cautions 1. If the rewrite-prohibited area of the boot cluster 0 overlaps with the flash shield window
range, prohibition to rewrite the boot cluster 0 takes priority.
2. The flash shield window can only be used for the code flash memory (and is not supported
for the data flash memory).
Table 26-11. Relationship Between Flash Shield Window Function Setting/Change Methods and Commands
Programming Conditions
Self-programming
Serial programming
Remark See 26.7 Security Settings to prohibit writing/erasing during serial programming.
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
Figure 26-11. Flash Shield Window Setting Example
(Target Devices: R5F11AGG, Start Block: 04H, End Block: 06H)
FFFF H
Flash shield
range
01C00H
01BFFH
0 1 0 00H
00FFFH
Flash shield
range
0 0 0 00H
Window Range
Setting/Change Methods
Specify the starting and
ending blocks by the
flash self-programming
library.
Specify the starting and
ending blocks on GUI of
dedicated flash memory
programmer, etc.
Block 7FH
Block 7EH
√: Serial programming
×: Self-programming
Block 06H
(end block)
√: Serial programming
Block 05H
√: Self-programming
Block 04H
(start block)
Block 03H
Block 02H
√: Serial programming
×: Self-programming
Block 01H
Block 00H
Block Erase
Block erasing is enabled
only within the window
range.
Block erasing is enabled
also outside the window
range.
CHAPTER 26 FLASH MEMORY
Methods by which writing can be performed
Execution Commands
Write
Writing is enabled only
within the range of
window range.
Writing is enabled also
outside the window
range.
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