STMicroelectronics STM32WL5 Series User Manual

Embedded flash memory (FLASH) RM0453
116/1450 RM0453 Rev 5
• For FSD and SFSA option, the value of mismatch is “flash memory completely
secured”.
• For BRSD, SBRSA and NBRSD, SNBRASA options, the value of mismatch is none
secured (memories are erased).
• For DDS option, the value of mismatch is “CPU2 debug disabled”.
• For C2OPT and SBRV options, the value of mismatch is “CPU2 boot from start address
of last flash page”.
• For HDPAD and HDPSA options, the value on mismatch is “Complete flash memory
hide protected”.
• For SUBGHSPISD option, the value of mismatch is “sub-GHz radio SPI secure”.
• For OPTVAL option, the value of mismatch is “not valid”. OPTVAL is a check word
programmed at the last user option address. It is used to check if all user options have
been programmed during an OPTSTART. If the user option program sequence has not
terminated completely, OPTVAL is not be programmed and OPTNV is set.
If the OPTVAL option indicates “not valid”, the flash memory is secured and fully hide
protected, SRAM1, SRAM2, and PKA SRAM memories are erased, CPU2 debug is
disabled, sub-GHz radio SPI is secured.
On system reset rising, internal option registers are copied into the following option registers
that can be read and written by software:
• FLASH_OPTR
• FLASH_PCROP1xSR (x = A or B)
• FLASH_PCROP1xER (x = A or B)
• FLASH_WRP1xR (x = A or B)
• FLASH_IPCCDBA
• FLASH_SFR
• FLASH_SRRVR
These registers are also used to modify the options. If these registers are not modified by
the user, they reflect the options states of the system. See Modify user options for more
details.
Table 17. Option loading control
OPTVERR OPTNV Description
00
Options correctly loaded and OPTVAL is “Valid”.
Security is applied according to options.
0 1 Does not occur
10
OPTVAL option is correctly loaded as “Valid” but some or all other options and engineering
bits are corrupted: mismatch values are loaded.
– When secure option is loaded correctly, security is applied according to the loaded secure
option values.
– When secure option is corrupted, security is applied on the full memory as indicated by the
loaded mismatch value.
11
Some or all options and engineering bits are corrupted: mismatch values are loaded.
OPTVAL is correctly loaded as “not Valid”.
Security applied on full memories irrespective of the loaded secure option values.

STMicroelectronics STM32WL5 Series Specifications

General

Brand	STMicroelectronics
Model	STM32WL5 Series
Category	Microcontrollers
Language	English