
RM0453 Rev 2
115/1454
RM0453
Embedded Flash memory (FLASH)
153
If the comparison between the word and its complement fails, a status bit OPTVERR is set.
Mismatch values are forced into the option registers as follows:
•
For USR OPT option, the value of mismatch is all options at ‘1’, except for BOR_LEV
that is “000” (lowest threshold).
•
For WRP option, the value of mismatch is the default value “No protection”.
•
For RDP option, the value of mismatch is the default value “Level 1”.
•
For PCROP, the value of mismatch is “all memory protected”.
•
For CxBOOT_LOCK option, the value of mismatch is “CPU1 boot lock disabled”,
“CPU2 boot lock disabled”.
•
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.
Table 17. Option loading control
OPTVERR OPTNV
Description
0
0
Options correctly loaded and OPTVAL is “Valid”.
Security is applied according to options.
0
1
Does not occur
1
0
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.
1
1
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.