ST STM32WL55JC User Manual

Embedded Flash memory (FLASH) RM0453
120/1454 RM0453 Rev 2
Note: Full mass erase or partial mass erase is performed only when level 1 is active and level 0 is
requested. When the protection level is increased (0→1, 1→2, 0→2, or directly decreased
from level 2 to level 0), there is no mass erase.
To validate the protection level change, the option bytes must be reloaded through the
OBL_LAUNCH bit in FLASH_CR, or a POR, or wakeup from Standby or Shutdown mode.
Figure 8. Changing the RDP level
MSv62613V1
Options write (RDP level increase) includes:
- Options page erase
- New options program
RDP ≠ 0xAA and RDP ≠ 0xCC
Others options modified
Write options including
RDP = 0xAA
Write options including
RDP = 0xCC
Write options including
RDP ≠ 0xCC and RDP ≠ 0xAA
Level 1
RDP ≠ 0xAA
RDP ≠ 0xCC
default
Level 2
RDP = 0xCC
Level 0
RDP = 0xAA
RDP = 0xAA
Other(s) option(s) modified
Write options including
RDP = 0xCC
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
Options write (RDP level identical) includes:
- Options page erase
- New options program
RDP = 0xCC
Others options modified
Write options including
RDP ≠ 0xCC and RDP ≠ 0xAA
Write options including
RDP = 0xAA
Secure CPU2 options write (RDP level identical) includes:
- Options page erase
- New options program
Secure CPU2 options write (RDP level decrease) includes:
- Options page erase
- New options program
Table 20. Access status versus protection level and execution modes
Area
Protection
level
User execution (BootFromFlash)
Debug/ BootFromRam/
BootFromLoader/|BootFromSFI
/RSS
Read Write Erase Read Write Erase
Main Flash
memory
1 Yes Yes Yes No No No
(4)
2 Yes Yes Yes N/A
(1)
N/A
(1)
N/A
(1)
System
memory
(2)
1Yes No No YesNoNo
2 Yes No No N/A
(1)
N/A
(1)
N/A
(1)
Option bytes
1Yes Yes
(3)
Yes Yes Yes
(3)
Yes
2Yes
CPU1 and CPU2
none secure - No
CPU1 and CPU2
none secure - No
N/A
(1)
N/A
(1)
N/A
(1)
CPU2 secure - Yes CPU2 secure - Yes
Backup
registers
1 Yes Yes N/A No No No
(4)
2Yes Yes N/A N/A
(1)
N/A
(1)
N/A
(1)
SRAM2
1 Yes Yes N/A No No No
(5)
2Yes Yes N/A N/A
(1)
N/A
(1)
N/A
(1)

ST STM32WL55JC Specifications

General

Brand	ST
Model	STM32WL55JC
Category	Microcontrollers
Language	English