PM0212

Memory protection strategy

Doc ID 022351 Rev 2

11/22

the FLASH_DUKR register, new keys can be entered without the device being previously

reset.

The size of the DATA area can be configured through the DATASIZE option byte.

In order to be as effective as possible, the application software must lock again the

unwanted memory access protection as soon as the programming is completed. Otherwise,

the protection level of the MASS is significantly reduced. To activate the MASS protection

again, the user must reset the corresponding bits in the FLASH_IAPSR register (DUL bit for

data EEPROM or PUL bit for Flash program memory).

Note:

1

The mechanism to lock and unlock unwanted memory access protection is identical for

option bytes and data EEPROM (see Table 4: MASS).

2

Before starting programming program memory or data EEPROM, the software must verify

that the area is not write protected by checking that the PUL or DUL bit is effectively set.