Table 20. Access Status Versus Protection Level And Execution Modes; Figure 8. Changing The Rdp Level - STMicroelectronics STM32WL5 Series Reference Manual

RM0453
Options write (RDP level increase) includes:
- Options page erase
- New options program
Options write (RDP level decrease) includes:
- Full mass erase or partial mass erase to not erase secure and or PCROP pages
- Backup registers and SRAM2 erase
- Options page erase
- New options program

Table 20. Access status versus protection level and execution modes

Protection
Area
level
1
Main flash
memory
2
1
System
(2)
memory
2
1
Option bytes
2
1
Backup
registers
2
1
SRAM2
2
1. When the protection level 2 is active, the debug port, the boot from RAM and the boot from system memory are disabled.
2. The system memory is only read-accessible, whatever the protection level (0, 1 or 2) and execution mode.
3. The flash non secure main memory is erased when the RDP option byte is programmed from level 1 to level 0. The flash
secure main memory is also erased when the ESE option byte is regressed at the same time as the RDP option byte
programming from level 1 to level 0.
4. The backup registers are erased when RDP changes from level 1 to level 0.

Figure 8. Changing the RDP level

Write options including
RDP = 0xCC
Level 2
RDP = 0xCC
Write options including
User execution (BootFromFlash)
Read Write
Yes Yes
Yes Yes
Yes No
Yes No
Yes Yes
CPU1 and CPU2
none secure - No
Yes
CPU2 secure - Yes CPU2 secure - Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Write options including
Level 1
0xAA
0xCC
default
RDP
RDP = 0xAA
Options write (RDP level identical) includes:
Secure CPU2 options write (RDP level identical) includes:
Secure CPU2 options write (RDP level decrease) includes:
Erase
Yes
Yes
No
No
(3)
Yes
CPU1 and CPU2
none secure - No
N/A
N/A
N/A
N/A
RM0453 Rev 5
Embedded flash memory (FLASH)
RDP = 0xAA
Level 0
RDP = 0xAA
Other
- Options page erase
- New options program
- Options page erase
- New options program
- Options page erase
- New options program
Debug/ BootFromRam/
BootFromLoader/|BootFromSFI
/RSS
Read Write
No No
(1)
N/A N/A
Yes No
(1)
N/A N/A
Yes Yes
(1)
N/A N/A
No No
(1)
N/A N/A
No No
(1)
N/A N/A
MSv62613V1
Erase
(4)
No
(1) (1)
N/A
No
(1) (1)
N/A
(3)
Yes
(1) (1)
N/A
(4)
No
(1) (1)
N/A
(5)
No
(1) (1)
N/A
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