Table 19. Rdp Regression From Level 1 To Level 0 And Memory Erase - ST STM32WL5 Series Reference Manual

RM0453
FLASH_PCROP1AER. Backup registers (RTC_BKPxR in the RTC), SRAM1, SRAM2 and
PKA SRAM are also erased. The user options except PCROP protection are set to their
previous values copied from FLASH_OPTR, FLASH_WRP1xR (x= A or B). PCROP is
disabled. The OTP area is not affected by mass erase and remains unchanged.
If the bit PCROP_RDP is cleared in FLASH_PCROP1AER, the full mass erase is replaced
by a partial mass erase that is successive page erases, except for the pages protected by
PCROP. This is done in order to keep the PCROP code. Only when the Flash memory is
erased, options are re-programmed with their previous values. This is also true for
FLASH_PCROP1xSR and FLASH_PCROP1xER registers (x= A or B).
If the CPU2 is secure (ESE = 1) the full mass erase is replaced by a partial mass erase that
is successive page erases, except for the pages protected by CPU2 security (SFSA). This is
done in order to keep the CPU2 secure code.

Table 19. RDP regression from level 1 to level 0 and memory erase

ESE PCROP
None
Partial
0
Complete
None
Partial
1
partial
Complete
non-secure
1
complete x
Flash
None
Partial
1 → 0
Complete
non-secure
PCROP_RDP
x
Flash, SRAM1, SRAM2, PKA SRAM and backup registers mass erase
1
Flash multiple page erase of all non-PCROP pages
SRAM1, SRAM2, PKA SRAM and backup registers erased (PCROP
Flash pages conserved)
0
Flash, SRAM1, SRAM2 and backup registers conserved
PKA SRAM erase.
x Flash multiple page erase of all non-secure pages
SRAM1, SRAM2, PKA SRAM and backup registers erased (secure Flash
1
pages conserved)
Flash multiple page erase of all non-PCROP pages and non-secure
pages
SRAM1, SRAM2, PKA SRAM and backup registers erased (PCROP
0
Flash pages and secure Flash pages conserved)
Flash, SRAM1, SRAM2, and backup registers conserved
PKA SRAM erased
Flash, SRAM1, SRAM2, and backup registers conserved
x
PKA SRAM erased
x
Flash, SRAM1, SRAM2, PKA SRAM and backup registers mass erased
1
Flash multiple page erase of all non-secure non-PCROP pages and
secure pages
SRAM1, SRAM2, PKA SRAM and backup registers erased (non-secure
PCROP Flash pages conserved)
0
Flash multiple page erase of all secure pages
SRAM1, SRAM2, PKA SRAM and backup registers erased (non-secure
PCROP Flash pages conserved)
Comment
RM0453 Rev 1
Embedded Flash memory (FLASH)
119/1461
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