Embedded Flash memory (FLASH) for category 3 devices RM0440
116/2126 RM0440 Rev 4
Securable memory area Bank 2 option bytes
Flash memory address: 0x1FFF F828
ST production value: 0xFF00 FF00
3.4.2 Option bytes programming
After reset, the options related bits in the Flash control register (FLASH_CR) are write-
protected. To run any operation on the option bytes page, the option lock bit OPTLOCK in
the Flash control register (FLASH_CR) must be cleared. The following sequence is used to
unlock this register:
1. Unlock the FLASH_CR with the LOCK clearing sequence (refer to Unlocking the Flash
memory).
2. Write OPTKEY1 = 0x08192A3B in the Flash option key register (FLASH_OPTKEYR).
3. Write OPTKEY2 = 0x4C5D6E7F in the FLASH_OPTKEYR register.
The user options can be protected against unwanted erase/program operations by setting
the OPTLOCK bit by software.
Note: If LOCK is set by software, OPTLOCK is automatically set too.
Bits 22:16 WRP2B_END: WRP second area “B” end offset
DBANK=1
WRP2B_END contains the last page of the WRP second area for bank2.
DBANK=0
WRP2B_END contains the last page of the WRP fourth area for all memory.
Bits 15:7 Reserved, must be kept at reset value.
Bits 6:0 WRP2B_STRT: WRP second area “B” start offset
DBANK=1
WRP2B_STRT contains the first page of the WRP second area for bank2.
DBANK=0
WRP2B_STRT contains the first page of the WRP second area for all memory.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Res. Res. Res. Res. Res. Res. Res. Res. SEC_SIZE2[7:0]
rw rw rw rw rw rw rw rw
Bits 31:8 Reserved, must be kept at reset value.
Bits 7:0 SEC_SIZE2: Securable memory area size contains the number of Securable
Flash memory pages.